- Chemoselective deprotection of 1,3-oxathiolanes using Amberlyst 15 and glyoxylic acid under solvent free conditions
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Carbonyl compounds were regenerated from corresponding 1,3-oxathiolanes via equilibrium exchange with glyoxylic acid and Amberlyst 15 as the heterogeneous catalyst, under solvent free conditions.
- Chavan,Soni,Kamat
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- Organoselenium-Catalyzed Oxidative Allylic Fluorination with Electrophilic N-F Reagent
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An efficient route of organoselenium-catalyzed oxidative allylic fluorination has been developed. In this transformation, bulky electrophilic fluorinating reagent N-fluoro-2,4,6-trimethylpyridinium triflate (TMFP-OTf) was employed as the oxidant and fluorine source. Notably, TEMPO as an additive affects the fluorination and leads to better substrate scope and excellent functional group tolerance. By this protocol, a variety of allylic fluorides were synthesized in good to excellent yields. The obtained allylic fluorides could be converted into vinyl fluorides efficiently in the presence of an appropriate base.
- Guo, Ruizhi,Huang, Jiachen,Zhao, Xiaodan
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- Highly enantioselective control of dynamic cascade transformations by dual catalysis: Asymmetric synthesis of polysubstituted spirocyclic oxindoles
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The highly enantioselective (up to >99.5:0.5 er) synthesis of polysubstituted spirocyclic oxindoles with four new contiguous stereocenters, including the spiro all-carbon quaternary center, is disclosed. It is accomplished by the highly stereoselective control of a dynamic conjugate/intramolecular allylic alkylation relay sequence based on the synergistic cooperation of metal and chiral amine catalysts in which the careful selection of organic ligand, metal complex, and chiral amine is essential. The intramolecular C-C bond-forming step occurred only when both the metal and chiral amine catalysts were present. (Chemical Equation Presented).
- Afewerki, Samson,Ma, Guangning,Ibrahem, Ismail,Liu, Leifeng,Sun, Junliang,Crdova, Armando
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- Retro-Diels-Alder Cleavage of endo-Bicyclohepta-5-en-2-ol
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endo-Bicyclohepta-5-en-2-ol (1a) on reaction with phenylmagnesium bromide was found to yield 1-phenylethanol, arising from a retro-Diels-Alder cleavage into cyclopentadiene and acetaldehyde.
- Prasad, J. V. N. Vara,Iyer, Padmini,Pillai, C. N.
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- A convenient oxidative deprotection of tetrahydropyranyl ethers with iron (III) nitrate and clay under microwave irradiation in solvent free conditions
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The efficient and environmentally benign oxidative deprotection of tetrahydropyranyl ethers using montmorillonite supported iron(III) nitrate under microwave irradiation under solvent free conditions is described.
- Heravi, Majid M.,Ajami, Dariush,Mojtahedi, Mohammad M.,Ghassemzadeh, Mitra
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- Aspects of Selective Oxidation and Ammoxidation Mechanisms over Bismuth Molybdate Catalysts. 3. Substituent Effects in the Selective Oxidation of Allylbenzenes
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The relative rates of catalytic oxidation of p-XC6H4CH2CH=CH2 (X=H, CH3, Cl, OCH3) at 320 deg C over MoO3, Bi2MoO6, Bi2Mo3O12, and a multicomponent system (Ma2+Mb3+BixMoyOz) have been determined at low ( H > CH3 > OCH3) and decreasing Bi content in the catalyst (Bi2MoO6 > Bi2Mo3O12 > MoO3).The results are interpreted in terms of the formation of a radical-like phenylallyl-molybdenum surface ? complex in the rate-determining step and, subsequently, the corresponding ?-O molybdate complex which is the intermediate for both cinnamaldehyde and indene formation.These results strongly suggest that in the selective oxidation of propylene over bismuth molybdate catalysts the ?-allylic surface complex formed in the rate-determining step is radical-like in character.
- Burrington, J. D.,Kartisek, C. T.,Grasselli, R. K.
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- Silica gel supported chromium trioxide: An efficient reagent for oxidative cleavage of oximes to carbonyl compounds under mild condition
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A facile, efficient oxidative deblocking of aldoximes and ketoximes to their corresponding aldehydes and ketones have been achieved by using silica gel supported chromium trioxide.
- Bendale, Pravin M.,Khadilkar, Bhushan M.
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- Silver(i)-catalysed carboxylative cyclisation of primary propargylic amines in neat water using potassium bicarbonate as a carboxyl source: An environment-friendly synthesis of: Z -5-alkylidene-1,3-oxazolidin-2-ones
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Herein, we report a mild and environment-friendly synthesis of Z-5-alkylidene-2-oxazolidinones in neat water, using a low loading (2 mol%) of silver carbonate as a catalyst. Instead of pressurised gaseous carbon dioxide, potassium bicarbonate was used as the source of carboxyl. An interesting solvent effect and a C-N cleavage side reaction with a 6-endo-dig mechanism are also discussed.
- Qin, Jian-Feng,Wang, Bing,Lin, Guo-Qiang
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- Preparation and characterization of laccases immobilized on magnetic nanoparticles and their application as a recyclable nanobiocatalyst for the aerobic oxidation of alcohols in the presence of TEMPO
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Laccase from Trametes versicolor was immobilized on a modified magnetic nanoparticle (MNP-Laccase) through a covalent attachment method. The morphology, structure, magnetic property and chemical composition of the immobilized laccase (MNP-Laccase) were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), alternating gradient force magnetometry (AGFM), energy-dispersive X-ray spectroscopy (EDX) and thermogravimetric analysis (TGA) techniques. The MNPs-Laccase retained the activity and exhibited higher resistance to pH and temperature changes. We have used MNPs-Laccase as a magnetically recoverable nanobiocatalyst for the mild, environmentally friendly and selective aerobic oxidation of benzylic and allylic alcohols to corresponding aldehydes in the presence of TEMPO as a redox mediator at room temperature. The magnetic nanobiocatalyst was easily and rapidly recovered by applying an external magnet device and reused up to 6 reaction runs without considerable loss of reactivity.
- Rouhani, Shamila,Rostami, Amin,Salimi, Abdollah
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- Efficient catalytic systems based on cobalt for oxidation of ethylbenzene, cyclohexene and oximes in the presence of N-hydroxyphthalimide
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The selective oxidation of ethylbenzene and cyclohexene to acetophenone and 2-cyclohexene-1-one using N-hydroxyphthalimide (NHPI) under oxygen atmosphere in the presence of an SiO2/Al2O3-supported cobalt catalyst occurs with conversions of 83 and 75% and selectivities of 99%. The supported cobalt is also a suitable and efficient catalyst for the oxidative deprotection of oximes to the corresponding carbonyl compounds. The reaction conditions have been optimized considering the effect of various parameters such as reaction time, amount of catalyst, temperature and reusability of the catalyst after several runs. Moreover, some possible mechanisms for the oxidation of ethylbenzene, cyclohexene and oximes have been proposed.
- Habibi,Faraji,Arshadi,Heydari,Gil
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- Catalytic oxidation of aromatic oxygenates by the heterogeneous catalyst Co-ZIF-9
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The catalytic activity of Co-ZIF-9, a zeolitic imidazolate framework of sodalite topology, in the oxidation of small aromatic molecules including phthalan, vanillyl alcohol, guaiacol, syringol, veratryl alcohol, and cinnamyl alcohol by molecular oxygen has been investigated. Co-ZIF-9 selectively oxidized the substrates and thus represents a promising heterogeneous catalyst for the oxidation of small aromatic substrates. Phthalan was converted to three different products, i.e. phthalide, phthalaldehyde, and small amounts of phthalic acid. In addition to phthalan, the alcohol functionality of vanillyl alcohol, veratryl alcohol, and cinnamyl alcohol was also similarly oxidized to yield the corresponding aldehydes in high yields and excellent selectivity. The effect of solvent, temperature and NaOH addition on the Co-ZIF-9 catalytic system has been studied. The presence of NaOH in the solution greatly enhanced the oxidation activity. The structure and stability of the heterogeneous catalyst was probed by UV-vis diffuse reflection spectroscopy, confirming the coordination geometry of cobalt in the catalyst framework, thermal gravimetric analysis, establishing the thermal stability of the structure, and XRD to monitor crystallinity of the catalyst. The heterogeneous nature of the catalyst was established by a hot filtration experiment, ICP analysis of the liquid phase, and by UV-vis absorption spectroscopy on the hot filtered reaction mixture.
- Zakzeski, Joseph,Dbczak, Agnieszka,Bruijnincx, Pieter C.A.,Weckhuysen, Bert M.
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- Studies on Transition-Metal Oxo and Nitrido Complexes. Part 11. New Oxo Complexes of Ruthenium as Aerobically assisted Oxidants, and the X-Ray Crystal Structure of *3.5H2O
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The new complexes t-py), nicotinic acid (Hnic), isonicotinamide (isna), pyridine-2-carboxylic acid (Hpyca), or1/2(2,2'-bipyridyl) (bipy)> have been prepared and the X-ray crystal structure of another member of the series, *3.5H2O, determined , a = 7.943(1), b = 8.952(2), c = 9.257(3) Angstroem, α = 98.76(2), β = 95.75(2), γ = 98.08(1) deg, Z = 1, R = 0.065>.New complexes are also reported of the types trans-2+ , trans- (L = 4But-py or 4-chloropyridine), trans- and trans-- (L = py, 4But-py, 3-methylpyridine, or 3,4-dimethylpyridine).Vibrational spectra, structures and reactions of these species are discussed: they function as overall four-electron oxidants (eight-electron in the case of , converting primary alcohols into aldehydes and secondary alcohols into ketones, and function catalytically with N-methylmorpholine N-oxide or iodosylbenzene as co-oxidant.The most soluble of them, trans-*3.5H2O, trans-t-py)4>, trans-2+, and trans-t-py)>-, will also effect such oxidation of alcohols with dioxygen as co-oxidant.
- Dengel, Andrew C.,El-Hendawy, Ahmed M.,Griffith, William P.,O'Mahoney, Caroline A.,Williams, David J.
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- Design, synthesis, molecular modelling, and in vitro evaluation of tricyclic coumarins against Trypanosoma cruzi
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Chagas disease is caused by infection with the parasite protozoan Trypanosoma cruzi and affects about 8 million people in 21 countries in Latin America. The main form of treatment of this disease is still based on the use of two drugs, benznidazole and nifurtimox, which both present low cure rates in the chronic phase and often have serious side-effects. Herein, we describe the synthesis of tricyclic coumarins that were obtained via NHC organocatalysis and evaluation of their trypanocidal activity. Molecular docking studies against trypanosomal enzyme triosephosphate isomerase (TIM) were carried out, as well as a theoretical study of the physicochemical parameters. The tricyclic coumarins were tested in vitro against the intracellular forms of Trypanosoma cruzi. Among the 18 compounds tested, 10 were more active than the reference drug benznidazole. The trypanocidal activity of the lead compound was rationalized by molecular docking study which suggested the strong interaction with the enzyme TIM by T.?cruzi and therefore indicating a possible mode of action. Furthermore, the selectivity index of eight tricyclic coumarins with high anti-T.?cruzi activity was above 50 and thus showing that these lead compounds are viable candidates for further in vivo assays.
- Coelho, Gleicekelly Silva,Andrade, Josimara Souza,Xavier, Viviane Flores,Sales Junior, Policarpo Ademar,Rodrigues de Araujo, Barbara Caroline,Fonseca, Kátia da Silva,Caetano, Melissa Soares,Murta, Silvane Maria Fonseca,Vieira, Paula Melo,Carneiro, Claudia Martins,Taylor, Jason Guy
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- Controllable Encapsulation of "clean" Metal Clusters within MOFs through Kinetic Modulation: Towards Advanced Heterogeneous Nanocatalysts
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Surfactant-free tiny Pt clusters were successfully encapsulated within MOFs with controllable size and spatial distribution by a novel kinetically modulated one-step strategy. Our synthesis relies on the rational manipulation of the reduction rate of Pt i
- Liu, Hongli,Chang, Lina,Bai, Cuihua,Chen, Liyu,Luque, Rafael,Li, Yingwei
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- An enantioselective three-component reaction of diazoacetates with indoles and enals by iridium/iminium co-catalysis
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The first example of chiral secondary amine and iridium(i) co-catalyzed enantioselective three-component reaction of aryldiazoacetates, indoles and enals was rationally designed and developed to afford 3-substituted indole derivatives in good yields and with moderate diastereoselectivity as well as excellent enantioselectivity. This reaction is proposed to proceed through the enantioselective trapping of iridium(i)-associated zwitterionic intermediates via selective 1,4-addtition to the chiral amine activated enals.
- Li, Mingfeng,Guo, Xin,Jin, Weifeng,Zheng, Qing,Liu, Shunying,Hu, Wenhao
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- Synthesis, characterization, and catalytic activity of a water soluble copper(II) and nickel(II) heterobimetallic complex [CuNi(μ-OH)(μ-OH2)(μ-OAc)(bpy)2](ClO4)2 in aqueous medium in the absence of a base and co-catalyst
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A copper(II)–nickel(II)-based catalyst system has been synthesized and characterized by elemental analysis, molar conductance, mass spectra, magnetic moment, EPR, UV-Vis, IR spectroscopy, and cyclic voltammetry. The structure of the complex was established by X-ray crystallography. The complex is an efficient catalyst, which oxidizes primary and secondary alcohols to the corresponding aldehydes and ketones at 70?°C employing 15% H2O2 as the oxidant in the absence of a base and co-catalyst.
- Lal, Ram A.,Kumar, Arvind,Syiemlieh, Ibanphylla,Kurbah, Sunshine D.
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- Utilisation of gold nanoparticles on amine-functionalised UiO-66 (NH2-UiO-66) nanocrystals for selective tandem catalytic reactions
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Colloidal deposition of gold nanoparticles (Au NPs) onto NH2-UiO-66 nanocrystals has been demonstrated with the resulting hybrid catalyst proving robust and versatile for one-pot, heterogeneous conversions involving the selective oxidation of p
- Hinde, Christopher S.,Webb, William R.,Chew, Benny K. J.,Tan, Hui Ru,Zhang, Wen-Hua,Hor, T. S. Andy,Raja, Robert
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- Synthetic scope of Ru(OH)x/Al2O3-catalyzed hydrogen-transfer reactions: An application to reduction of allylic alcohols by a sequential process of isomerization/meerwein-ponndorf-verley-iype reduction
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Reduction of allylic alcohols can be promoted efficiently by the supported ruthenium catalyst Ru(OH)x/Al2O3. Various allylic alcohols were converted to saturated alcohols in excellent yields by using 2-propanol without any additives. This Ru(OHx/Al 2O3-catalyzed reduction of a dienol proceeds only at the allylic double bond to afford the corresponding enol, and chemoselective isomerization and reduction can be realized under similar conditions. The catalysis is truly heterogeneous and the high catalytic performance can be maintained during at least three recycles of the Ru(OH)x/Al 2O3 catalyst. The transformation of allylic alcohols to saturated alcohols consists of three sequential reactions: oxidation of allylic alcohols to α,β-un-saturated carbonyl compounds; reduction of α,β-unsaturated carbonyl compounds to saturated carbonyl compounds; and reduction of saturated carbonyl compounds to saturated alcohols.
- Kim, Jung Won,Koike, Takeshi,Kotani, Miyuki,Yamaguchi, Kazuya,Mizuno, Noritaka
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- Au-Pd nanoparticles on layered double hydroxide: Highly active catalyst for aerobic oxidation of alcohols in aqueous phase
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Au-Pd bimetal catalysts supported on layered double hydroxide (LDH) have been prepared and structurally characterized using XRD, TEM and XPS. The Au and Pd nanoparticles with an average of 3.4 ± 0.2 nm were highly dispersed on LDH. There was a strong electronic interaction between Au and Pd nanoparticles. The bimetallic catalyst afforded much higher catalytic performance than the corresponding monometallic catalyst for the alcohol oxidation in water. Especially, non-activated aliphatic primary alcohols can be oxidized into the corresponding acids nearly quantitatively over the bimetallic catalyst. The catalyst can be reused several times without obvious loss of its activity and selectivity.
- Shi, Yu,Yang, Hanmin,Zhao, Xiuge,Cao, Ting,Chen, Jizhong,Zhu, Wenwen,Yu, Yinyin,Hou, Zhenshan
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- Oxidation of alcohols to carbonyl compounds with a new potassium permanganate adsorbed on Kieselguhr reagent
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A new reagent, potassium permanganate adsorbed on kieselguhr, suitable for the oxidation of alcohols to the corresponding carbonyl compounds is described.
- Lou, Ji-Dong,Lou, Wen-Xing
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- Highly efficient, organocatalytic aerobic alcohol oxidation
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5-Fluoro-2-azaadamantane N-oxyl (5-F-AZADO) realizes a simple, organocatalytic aerobic alcohol oxidation system that has a wide scope under mild conditions at ambient pressure and temperature and is weakly acidic and halogen- and transition-metal-free. The oxoammonium nitrate (5-F-AZADO +NO3-) works as a bifunctional catalyst of 5-F-AZADO and NOx that enables the catalytic aerobic oxidation of alcohols by itself (a metal-salt-free system).
- Shibuya, Masatoshi,Osada, Yuji,Sasano, Yusuke,Tomizawa, Masaki,Iwabuchi, Yoshiharu
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- A convenient oxidative demasking of 1,3-dithiolanes and dithianes to carbonyl compounds with TBHP
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Regeneration of carbonyl compounds from their 1,3-dithiolanes and dithianes was achieved using tert-butyl hydroperoxide (TBHP, aq. 70%) in high yields. Thus, an efficient, economical and experimentally simple protocol for dethioacetalization has been demonstrated.
- Barhate, Nivrutti B,Shinde, Popat D,Mahajan, Vishal A,Wakharkar, Radhika D
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- Unveiling of a Trinuclear Cyclic Peroxidovanadate: A Potential Oxidant in Vanadium-Catalyzed Reactions
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The first peroxidovanadium trimer was prepared in the form of its tetrabutylammonium salt, (NBu4)3[V3O3(O2)6]·2H2O. Its X-ray structure analysis revealed a unique cyclic structur
- Krivosudsky, Luká?,Schwendt, Peter,Gyepes, Róbert
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- Development of manganese(VI) oxidising agents soluble in organic solvents
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Two manganate(VI) reagents have been prepared from permanganate salts that show excellent oxidising properties in common organic solvents. Georg Thieme Verlag Stuttgart · New York.
- Ellis, Rhys,Lee, Kee-Han,Ainsworth, Matthew,Kerr, Alexander,Viseux, Eddy M. E.
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- OXIDATION OF ALCOHOLS TO CARBONYL COMPOUNDS WITH CHROMIUM(V) REAGENTS
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Two pentavalent chromium complexes have been used effectively for the oxidation of alcohols to carbonyl compounds.
- Chakraborty, T. K.,Chandrasekaran, S.
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- Barium dichromate [BaCr2O7], a mild reagent for oxidation of alcohols to their corresponding carbonyls in non-aqueous polar aprotic media
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Barium dichromate is used as a mild oxidizing agent for the selective conversion of primary and secondary alcohols to their corresponding aldehydes and ketones, respectively. Over-oxidation does not occur and primary alcohols undergo oxidation to the aldehyde. Primary and secondary benzylic alcohols are oxidized faster and more efficiently. Barium dichromate is used as a mild oxidizing agent for the selective conversion of primary and secondary alcohols to their corresponding aldehydes and ketones, respectively. Over-oxidation does not occur and primary alcohols undergo oxidation to the aldehyde. Primary and secondary benzylic alcohols are oxidized faster and more efficiently.
- Mottaghinejad, Enayatollah,Shaafi,Ghasemzadeh
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- Oxidation of alcohols to carbonyl compounds under solvent-free conditions using permanganate supported on alumina
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A manupulatively simple and rapid method for oxidation of alcohols to the corresponding carbonyl compounds is described. The reaction is conduced under solventless 'dry' conditions using alumina-supported permanganate.
- Hajipour, Abdol Reza,Mallakpour, Shadpour E.,Imanzadeh, Gholamhasan
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- Selective aerobic oxidation of alcohols by using manganese oxide nanoparticles as an efficient heterogeneous catalyst
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Manganese oxide (Mn3O4) nanoparticles have been successfully innovated to be efficient catalysts not only for the aerobic oxidation of various alcohols to aldehydes or ketones, but also for the selective aerobic oxidation of mixed alcohols. Copyright
- Sun, Hua-Yin,Hua, Qing,Guo, Feng-Feng,Wang, Zhi-Yong,Huang, Wei-Xin
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- An easy and fast method for conversion of oximes to the corresponding carbonyl compounds under microwave irradiation
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1-Benzyl-4-aza-1-azoniabicyclo[2.2.2]octane dichromate has been found to be an efficient and new reagent for the conversion of oximes to the corresponding carbonyl compounds. The reaction is performed under microwave irradiation.
- Hajipour,Mallakpour,Khoee
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- Immobilized magnetic nano catalyst for oxidation of alcohol
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Covalent attachment of Schiff base on magnetic nanoparticles yielded good selectivity for oxidation of alcohols. The ferromagnetic interaction in the complex added comprehensive advantage in enhancing the catalytic activity of the nanocatalyst. A greener approach for alcohol oxidation was achieved in solventless method with good yield (>78%). Leaching experiments confirmed a strong interaction between magnetic support and complex. The catalyst showed significant conversion even after 5 catalytic runs.
- Bhat, Pooja B.,Rajarao, Ravindra,Sahajwalla, Veena,Bhat, Badekai Ramachandra
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- BIS(p-METHOXYPHENYL)SELENOXIDE AS A COOXIDANT FOR SELENIUM DIOXIDE OXIDATION OF BENZYL ALCOHOLS
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The title selenoxide provides a new oxidizing system in combination with catalytic selenium dioxide for oxidation of benzyl alcohols to benzaldehydes.An effective redox cycle between selenium and the dioxide is suggested.
- Ogura, Fumio,Otsubo, Tetsuo,Ariyoshi, Kimio,Yamaguchi, Hachiro
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- Effective oxidation of alcohols under heterogeneous conditions with a new reagent: Manganese dioxide supported on graphite
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A new reagent, manganese dioxide supported on graphite, under heterogeneous conditions at reflux is described for the oxidation of benzylic and allylic alcohols into the corresponding aldehydes and ketones, respectively. The main advantage of the present oxidation is that the insoluble solid support, graphite, provides a particular reaction environment capable of enhancing the reaction selectivity and reactivity. Moreover, it turns out to be very profitable in the workup, which becomes reduced to a mere filtration. The mechanism for this oxidation is also discussed. Copyright Taylor & Francis Group, LLC.
- Lou, Ji-Dong,Lu, Xiu Lian,Huang, Li-Hong,Wang, Qiang,Zou, Xiao-Nan
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- Mild, green copper/4-dimethylaminopyridine catalysed aerobic oxidation of alcohols mediated by nitroxyl radicals in water
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A novel copper/4-dimethylaminopyridine catalyst system has been found to catalyse the aerobic oxidation of a variety of primary and secondary alcohols in water at room temperature, in the presence of a TEMPO or ABNO nitroxyl radical. A tetranuclear CuII cluster was revealed to be a plausible reactive intermediate.
- Zhang, Guoqi,Yang, Chengxiong,Liu,Li, Li,Golen, James A.,Rheingold, Arnold L.
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- Highly Enantioselective Synthesis of Alkylpyridine Derivatives through a Michael/Michael/Aldol Cascade Reaction
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A method for the synthesis of pyridine derivatives based on a triple cascade reaction catalyzed by chiral secondary amines was developed. The resulting cyclohexenes (three C–C bonds were formed) were obtained in good yields with good diastereoselectivities and excellent enantioselectivities.
- Meazza, Marta,Potter, Michael,Pitak, Mateusz B.,Coles, Simon J.,Mazzanti, Andrea,Rios, Ramon
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- An Fe3O4@P4VP@FeCl3 core-shell heterogeneous catalyst for aerobic oxidation of alcohols and benzylic oxidation reaction
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A novel magnetic Fe3O4@P4VP(poly(4-vinylpyridine))@FeCl3 core-shell structure was successfully synthesized. Its Fe3O4@P4VP core was initially prepared via polymerization of 4-vinyl pyridine on the surface of Fe3O4 microspheres. The successful introduction of the FeCl3 moiety as a catalytic active site was achieved through coordination interaction between P4VP and FeCl3. The obtained Fe3O4@P4VP@FeCl3 catalyst was applied in the selective oxidation of alcohols using molecular oxygen as the oxidant. It was shown that a variety of alcohol substrates is tolerated under optimized reaction conditions. Additionally, benzylic oxidation of hydrocarbon compounds was also evaluated using Fe3O4@P4VP@FeCl3 as the catalyst and tBuOOH as the oxidant, achieving high yields and very good selectivities. The heterogeneity of the Fe3O4@P4VP@FeCl3 core-shell catalyst was tested and the initial activity was maintained after five reuses.
- Li, Ruilian,Zhao, Jian,Yang, Fengxia,Zhang, Yingchao,Ramella, Daniele,Peng, Yu,Luan, Yi
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- From surface-inspired oxovanadium silsesquioxane models to active catalysts for the oxidation of alcohols with O2-The cinnamic acid/ metavanadate system
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Silsesquioxane dioxovanadate(V) complexes were investigated with respect to their potential as a catalyst for the oxidative dehydrogenation of alcohols with O2 as an oxidant. The turnover frequencies determined were comparatively low, but during the oxidation of cinnamic alcohol an increase in activity was observed in the course of the process, which was inspected more closely. It turned out that during the oxidation of cinnamic alcohol, not only was the aldehyde formed but also cinnamic acid, which in turn reacts with the silsesquioxane complex employed to give NBu4- [O2V(O 2CC2H2Ph)2], which can also be obtained from NBu4VO3 and cinnamic acid and represents a far more active catalyst, not only for cinnamic alcohol but also for other activated alcohols and hydrocarbons. The rate-determining step of the conversion corresponds to an hydrogen-atom abstraction from the C-H units, as shown by the determination of the kinetic isotope effect in case of 9-hydroxyfluorene, and the reoxidation of the reduced catalyst proceeds via a peroxo intermediate, which is also capable of oxidizing one alcohol equivalent. Furthermore the influence of the organic residues at the carboxylate ligands on the catalyst performance was investigated, which showed that the activity increases with decreasing pKs value. Moreover, it was found that during the oxidation the catalyst slowly decomposes, but can be regenerated by addition of excessive carboxylic acid.
- Ohde, Christian,Limberg, Christian
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- Palladium-Catalyzed Allylic C-H Oxidative Annulation for Assembly of Functionalized 2-Substituted Quinoline Derivatives
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An efficient and practical palladium-catalyzed aerobic oxidative approach to afford functionalized 2-substituted quinolines in moderate to good yields from readily available allylbenzenes with aniline is developed. The present annulation process has high functional-group tolerance and high atom economy, making it a valuable and practical method in synthetic and medicinal chemistry. Moreover, this transformation is supposed to proceed through oxidation of allylic C-H functionalization to form C-C and C-N bonds in one pot.
- Li, Chunsheng,Li, Jianxiao,An, Yanni,Peng, Jianwen,Wu, Wanqing,Jiang, Huanfeng
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- A Copper(I) Complex with Two Unpaired Electrons, Synthesised by Oxidation of a Copper(II) Complex with Two Redox-Active Ligands
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Two homoleptic copper(II) complexes [Cu(L1)2] and [Cu(L2)2] with anionic redox-active ligands were synthesised, one with urea azine (L1) and the other with thio-urea azine (L2) ligands. One-electron oxidation of the complexes initiates an unprecedented redox-induced electron transfer process, leading to monocationic copper(I) complexes [Cu(L1)2]+ and [Cu(L2)2]+ with two oxidised ligands. While [Cu(L1)2]+ is best described as a CuI complex with two neutral radical ligands that couple antiferromagnetically, [Cu(L2)2]+ is a CuI complex with two clearly different ligand units in the solid state and with a magnetic susceptibility close to a diamagnetic compound. Further one-electron oxidation of the complex with L1 ligands results in a dication [Cu(L1)2]2+, best described as a CuI complex with a twofold oxidised, monocationic ligand and a neutral radical ligand. The stability in at least three redox states, the accumulation of spin density at the ligands and the facile ligand-metal electron transfer make these complexes highly attractive for a variety of applications; here the catalytic aerobic oxidation of alcohols to aldehydes is tested.
- Asyuda, Andika,Enders, Markus,Himmel, Hans-J?rg,Kaifer, Elisabeth,Werr, Marco,Zharnikov, Michael
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- Direct synthesis of Fe(III) immobilized Zr-based metal–organic framework for aerobic oxidation reaction
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A Zr-based metal–organic framework with bipyridine units (UiO-67) has been utilized for the immobilization of catalytically active iron species via a post-synthetic metalation method. UiO-67 bipyridine MOF was synthesized through a simple solvothermal method and was shown to have a UiO-type structure. Post-synthetic metalation of UiO-67 MOF was performed for the immobilization of the catalytically active FeCl3. FT-IR and EDX element map suggested that FeCl3 is coordinately bonded to the UiO-67 bipyridine framework. The synthesized UiO-67-FeCl3 catalyst was used for the aerobic oxidation of alcohols and benzylic compounds in the presence of molecular oxygen. In addition, the UiO-67-FeCl3 catalyst can be reused as a solid heterogeneous catalyst without compromising its activity and selectivity.
- Shu, Xin,Yu, Ying,Jiang, Yi,Luan, Yi,Ramella, Daniele
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- The Aldol Reaction under High-Intensity Ultrasound: A Novel Approach to an Old Reaction
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We have employed high-intensity ultrasound (HIU) to reinvestigate the aldol reaction (AR) in water. A number of aldols that under usual conditions would undergo elimination were isolated in acceptable to good yields. Within 15-30 min, acetophenone reacted with non-enolizable aldehydes to afford the aldol exclusively, while under conventional conditions (stirring or heating under reflux) the same compounds either failed to react or gave, after several hours, the enone, often in complex product mixtures. A library of polyols was obtained starting from a series of acetophenones and excess formaldehyde. Benzaldehyde reacted with a series of 1,3-dicarbonyl compounds to afford the corresponding bis(benzylidene) adducts. The results proved to be highly reproducible because the relevant sonochemical parameters were rigorously controlled. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
- Cravotto, Giancarlo,Demetri, Alberto,Nano, Gian Mario,Palmisano, Giovanni,Penoni, Andrea,Tagliapietra, Silvia
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- Evolution of physical and photocatalytic properties of new Zn(II) and Ru(II) complexes
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Synthesis of Zn(II) and Ru(II) complexes were reported by using N4-macrocyclic Schiff base ligands under solvothermal conditions. The newly synthesized Zn(II) and Ru(II) complexes have been characterized by various physico-chemical techniques such as elemental analysis, molar conductance, HRMS, TGA, FESEM, UV–Vis, FT-IR, 1H NMR, and cyclic voltammetry. By using molar conductance studies, the complexes are formulated as [Zn(TPTTP)]Cl2 and [Ru(TPTTP)Cl2]. C–H bond activation of an sp3 group of methylstyrenes (converted into cinnamaldehydes) and C–H bond activation of the sp2 bond of polycyclic aromatic hydrocarbons through photooxidation was examined in the presence of Zn(II) and Ru(II) complexes. Reusable activity studies and photostability of catalyst are investigated by using UV–Vis spectra. Based on the results, higher catalytic activity of [Ru(TPTTP)Cl2] complex than [Zn(TPTTP)]Cl2 complex in both C–H bond activation and photooxidation of aromatic hydrocarbons has been reported.
- Gugulothu, Venkanna,Ahemed, Jakeer,Subburu, Mahesh,Yadagiri, Bhongiri,Mittal, Ritu,Prabhakar, Chetti,Pola, Someshwar
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- Organische Synthesen mit Uebergangsmetall-Komplexen. LXV. Aldehyde durch Hydrolyse der M=C-Bindung von Alkoxycarben-Chromkomplexen mit Wasser / Urotropin. Ein zweikerniger verbrueckter (β-Amino)vinylcarben-Chromkomplex durch Fragmentierung von Urotropin
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The Cr=C bonds of aryl- and alkenyl(ethoxy)carbene chromium complexes 1a-d are hydrolysed under mild reaction conditions with high chemoselectivity in presence of hexamethylenetetramine (urotropine), 2, to give aldehydes 4a-d and (urotropine)Cr(CO)5, 3.The alkynyl(ethoxy)carbene chromium complex 1e reacts with urotropine in a completely different fashion and forms a binuclear (β-amino)vinylcarbene complex, 5, by fragmentation of the urotropine skeleton.
- Aumann, Rudolf,Hinterding, Peter,Krueger, Carl,Goddard, Richard
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- Microwave-assisted oxidation of alcohols using wet alumina supported ammonium chlorochromate in solventless system
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A simple and selective method for the oxidation of alcohols to carbonyl compounds is described that occurs on wet alumina supported ammonium chlorochromate under microwave irradiation in solventless system.
- Heravi, Majid M.,Aghayan, Maryam M.
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- Shaken not stirred; Oxidation of alcohols with sodium dichromate
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Efficient and selective oxidation of primary alcohols to the corresponding aldehydes with sodium dichromate at room temperature under solvent-free conditions by shaking is described. This new procedure can also successfully oxidise secondary alcohols.
- Lou, Ji-Dong,Gao, Chun-Ling,Ma, Yi-Chun,Huang, Li-Hong,Li, Li
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- Aerobic alcohol oxidation catalyzed by polyester-based Pd(II) macrocomplexes
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A 1:2 mixture of the poly (l-lactide)-based macrocomplex trans-[Pd(OAc)2(L1)2] (1) (L1 = macroligand) and of L1 showed to be an easily recoverable homogeneous catalyst for the aerobic oxidation of alcohols to aldehydes or ketones. Copyright
- Giachi, Guido,Frediani, Marco,Oberhauser, Werner,Passaglia, Elisa
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- An efficient Pd@Pro-GO heterogeneous catalyst for the α, β-dehydrogenation of saturated aldehyde and ketones
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An Efficient Pd@Pro-GO heterogeneous catalyst was developed that can promote the α, β-dehydrogenation of saturated aldehyde and ketones in the yield of 73% ? 92% at mild conditions without extra oxidants and additives. Pd@Pro-GO heterogeneous catalyst was synthesized via two steps: firstly, the Pro-GO was obtained by the esterification reaction between graphene oxide (GO) and N-(tert-Butoxycarbonyl)-L-proline (Boc-Pro-OH), followed by removing the protection group tert-Butoxycarbonyl (Boc), which endowed the proline-functionalized GO with both the lewis acid site (COOH) and the bronsted base site (NH), besides, the pyrrolidine of proline also can form imine with aldehydes to activate these substrates; Second, palladium was dispersed on the proline-functionalized GO (Pro-GO) to obtained heterogeneous catalyst Pd@Pro-GO. Mechanistic studies have shown that the Pd@Pro-GO-catalyzed α,β-dehydrogenation of saturated aldehyde and ketones was realized by an improved heterogeneously catalyzed Saegusa oxidation reaction. Based on the obove characteristics, the Pd@Pro-GO will be widely used in the transition metal catalytic field.
- Pan, Gao-Fei,Wang, Zhe,Chang, Yi-Yuan,Hao, Yue,Wang, Yi-Chen,Xing, Rui-Guang
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supporting information
(2021/12/30)
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- Markovnikov Wacker-Tsuji Oxidation of Allyl(hetero)arenes and Application in a One-Pot Photo-Metal-Biocatalytic Approach to Enantioenriched Amines and Alcohols
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The Wacker-Tsuji aerobic oxidation of various allyl(hetero)arenes under photocatalytic conditions to form the corresponding methyl ketones is presented. By using a palladium complex [PdCl2(MeCN)2] and the photosensitizer [Acr-Mes]ClO4 in aqueous medium and at room temperature, and by simple irradiation with blue led light, the desired carbonyl compounds were synthesized with high conversions (>80%) and excellent selectivities (>90%). The key process was the transient formation of Pd nanoparticles that can activate oxygen, thus recycling the Pd(II) species necessary in the Wacker oxidative reaction. While light irradiation was strictly mandatory, the addition of the photocatalyst improved the reaction selectivity, due to the formation of the starting allyl(hetero)arene from some of the obtained by-products, thus entering back in the Wacker-Tsuji catalytic cycle. Once optimized, the oxidation reaction was combined in a one-pot two-step sequential protocol with an enzymatic transformation. Depending on the biocatalyst employed, i. e. an amine transaminase or an alcohol dehydrogenase, the corresponding (R)- and (S)-1-arylpropan-2-amines or 1-arylpropan-2-ols, respectively, could be synthesized in most cases with high yields (>70%) and in enantiopure form. Finally, an application of this photo-metal-biocatalytic strategy has been demonstrated in order to get access in a straightforward manner to selegiline, an anti-Parkinson drug. (Figure presented.).
- Albarrán-Velo, Jesús,Gotor-Fernández, Vicente,Lavandera, Iván
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p. 4096 - 4108
(2021/08/19)
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- Method for preparing olefine aldehyde through catalytic oxidation of enol ether
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The invention relates to the technical field of olefine aldehyde preparation, and provides a method for preparing olefine aldehyde through catalytic oxidation of enol ether. According to the invention, a palladium catalyst, a copper salt, a solvent and enol ether are mixed and subjected to a catalytic oxidation reaction to obtain olefine aldehyde. According to the method, the copper salt is used as the oxidizing agent, the mixed solvent of water and acetonitrile is used as the reaction solvent, and the volume ratio of water to acetonitrile in the mixed solvent is controlled to be (3-7): (3-7), so that the catalytic oxidation reaction can be smoothly carried out in the mixed solvent with a specific ratio, and the generation of palladium black precipitate can be avoided. The method provided by the invention has the advantages of simple steps, low reagent cost, no need of dangerous reagents, wide substrate adaptability and small catalyst dosage. Furthermore, octadecane mercaptan is added to promote the catalytic oxidation reaction, and when the dosage of the palladium catalyst is extremely low, the olefine aldehyde yield can be greatly increased by adding octadecane mercaptan.
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Paragraph 0082-0088
(2021/06/23)
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- Nickel catalyzed hydrosilane reduction of (het)arenecarboxylic acids into aldehydes
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Nickel-catalyzed reduction of (het)arenecarboxylic acids with hydrosilanes in the presence of dimethyl dicarbonate as the activator affords the corresponding aldehydes. The role of the activator is the conversion of the acids into their anhydrides undergoing C–O cleavage. The good yields were achieved in case of substrates bearing electron-donating and electron-neutral groups.
- Wang, Liang,Wang, Yaoyao,Tao, Yu,Zhang, Nana,Li, Shubai
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p. 271 - 273
(2021/05/04)
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- The mechanism of the gold(i)-catalyzed Meyer-Schuster rearrangement of 1-phenyl-2-propyn-1-olvia4-endo-digcyclization
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With the aim of rationalizing the experimental counterion- and solvent-dependent reactivity in the gold(i)-catalyzed Meyer-Schuster rearrangement of 1-phenyl-2-propyn-1-ol, a computational mechanistic study unraveled the unexpected formation of a gold-oxetene intermediateviacommonly unfavorable 4-endo-digcyclization triggered by the counterion in low polarity solvents.
- Sorbelli, Diego,Segato, Jacopo,Del Zotto, Alessandro,Belpassi, Leonardo,Zuccaccia, Daniele,Belanzoni, Paola
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supporting information
p. 5154 - 5160
(2021/04/26)
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- Method for preparing olefine aldehyde by catalyzing terminal alkyne or terminal conjugated eneyne and diphosphine ligand used in method
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The invention discloses a method for preparing olefine aldehyde by catalyzing terminal alkyne or terminal conjugated eneyne and a diphosphine ligand used in the method. According to the invention, indole-substituted phosphoramidite diphosphine ligand which is stable in air and insensitive to light is synthesized by utilizing a continuous one-pot method, and the indole-substituted phosphoramidite diphosphine ligand and a rhodium catalyst are used for jointly catalyzing to successfully achieve a hydroformylation reaction of aromatic terminal alkyne and terminal conjugated eneyne under the condition of synthesis gas for the first time, so that an olefine aldehyde structure compound can be rapidly and massively prepared, and particularly, a polyolefine aldehyde structure compound which is more difficult to synthesize in the prior art can be easily prepared and synthesized, and a novel method is provided for synthesis and modification of drug molecules, intermediates and chemical products.
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Paragraph 0126-0131
(2021/05/29)
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- Rapid, chemoselective and mild oxidation protocol for alcohols and ethers with recyclable N-chloro-N-(phenylsulfonyl)benzenesulfonamide
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Chlorine is the 20th most abundant element on the earth compared to bromine, iodine, and fluorine, a sulfonimide reagent, N-chloro-N-(phenylsulfonyl)benzenesulfonamide (NCBSI) was identified as a mild and selective oxidant. Without activation, the reagent was proved to oxidize primary and secondary alcohols as well as their symmetrical and mixed ethers to corresponding aldehydes and ketones. With recoverable PS-TEMPO catalyst, selective oxidation over chlorination of primary and secondary alcohols and their ethers with electron-donating substituents was achieved. The reagent precursor of NCBSI was recovered quantitatively and can be reused for synthesizing NCBSI.
- Badani, Purav,Chaturbhuj, Ganesh,Ganwir, Prerna,Misal, Balu,Palav, Amey
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supporting information
(2021/06/03)
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- Homogeneous CuCl2/TMEDA/TEMPO-Catalyzed chemoselective base- and halogen- free aerobic oxidation of primary alcohols in mild conditions
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This article describes the developing of a base- and halogen- free homogeneous system aiming to chemoselectively oxidize allyl, furyl, aryl and heteroaryl primary alcohols. The current easy-to-handle aerobic system uses few amounts of CuCl2/TMEDA/TEMPO system under mild reaction conditions to produce aldehydes in high yields. Moreover, the CuCl2/TMEDA cyclic voltammetry was measured for the first time, disclosing that TMEDA as ligand substantially affects the redox potential (E1/2) of the couple E1/2Cu2+/Cu+ to E1/2Cu2+/Cu+-TMEDA by 454 mV in the redox system.
- Alves, Otávio A. L.,Chagas, Rafael C. R.,Princival, Jefferson L.,Ribeiro, RogérioT.,Silva, Emmanuel D.,Villar, José A. F. P.
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- Nitrosoarene-Catalyzed HFIP-Assisted Transformation of Arylmethyl Halides to Aromatic Carbonyls under Aerobic Conditions
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A rare metal-free nucleophilic nitrosoarene catalysis accompanied by highly hydrogen-bond-donor (HBD) solvent, 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), organocatalytically converts arylmethyl halides to aromatic carbonyls. This protocol offers an effective means to access a diverse array of aromatic carbonyls with good chemoselectivity under mild reaction conditions. The activation of arylmethyl halides by HFIP to generate stable carbocation and autoxidation of in situ generated hydroxylamine to nitrosoarene in the presence of atmospheric O2 are the keys to success.
- Pradhan, Suman,Sharma, Vishali,Chatterjee, Indranil
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supporting information
p. 6148 - 6152
(2021/08/03)
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- Preparation method for catalytic synthesis of dihydropyrone compound containing 1, 3-enyne functional group by N-heterocyclic carbene
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The invention discloses a preparation method for catalytic synthesis of dihydropyrone compound containing 1, 3-enyne functional group by N-heterocyclic carbene, which is characterized in that the derivative is shown as a general formula (1), in the formula, R1 is phenyl, substituted benzene, naphthalene, furan, thiophene or alkyl; R2 is phenyl, substituted benzene, furan or thiophene; and R3 is phenyl, substituted benzene, thiophene or alkyl. The dihydropyrone compound containing 1,3-enyne functional group can be effectively and efficiently prepared from reactant molecules alpha, beta-unsaturated aldehyde and 1,3-enyne aldehyde with simple structural units under the catalysis of N-heterocyclic carbene, and the dihydropyrone derivative has the advantages of good substrate universality, excellent yield, high enantioselectivity and the like.
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Paragraph 0014-0015
(2021/01/12)
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- Catalytic alcohol oxidation using cationic Schiff base manganeseIII complexes with flexible diamino bridge
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Four Schiff base manganese(III) complexes with derivatives of [(R,R)-N,N’-bis(salicy1idene)-1,2-cyclohexanediaminato)] including substituents on salicylaldehyde such as 3-methoxy, 3,5-di-tert-butyl and 3,5-chloro were synthesized and characterized using a combination of IR, UV–Vis, and HR ESI-MS techniques. The catalytic activity of these complexes was tested in the oxidation of 1-phenylethanol to acetophenone, revealing very good performances for all of the four manganese complexes. The catalytic reactions were carried out in the presence of tert-butyl hydroperoxide (TBHP) as oxidant and imidazole as co-catalyst. Complex Mn-4, bearing electron withdrawing [(R,R)-N,N’-bis(3,5-di-chloro-salicylidene)-1,2-cyclohexanediaminato)] ligand was found to be the most stable of the tested Mn(III) complexes and was selected for the oxidation of several primary and secondary alcohols.
- Kakavand, Meysam,Mastrorilli, Piero,Mesto, Ernesto,Neshat, Abdollah,Osanlou, Farzane,Schingaro, Emanuela,Todisco, Stefano
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- Liquid-phase oxidation of olefins with rare hydronium ion salt of dinuclear dioxido-vanadium(V) complexes and comparative catalytic studies with analogous copper complexes
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Homogeneous liquid-phase oxidation of a number of aromatic and aliphatic olefins was examined using dinuclear anionic vanadium dioxido complexes [(VO2)2(salLH)]? (1) and [(VO2)2(NsalLH)]? (2) and dinuclear copper complexes [(CuCl)2(salLH)]? (3) and [(CuCl)2(NsalLH)]? (4) (reaction of carbohydrazide with salicylaldehyde and 4-diethylamino salicylaldehyde afforded Schiff-base ligands [salLH4] and [NsalLH4], respectively). Anionic vanadium and copper complexes 1, 2, 3, and 4 were isolated in the form of their hydronium ion salt, which is rare. The molecular structure of the hydronium ion salt of anionic dinuclear vanadium dioxido complex [(VO2)2(salLH)]? (1) was established through single-crystal X-ray analysis. The chemical and structural properties were studied using Fourier transform infrared (FT-IR), ultraviolet–visible (UV–Vis), 1H and 13C nuclear magnetic resonance (NMR), electrospray ionization mass spectrometry (ESI-MS), electron paramagnetic resonance (EPR) spectroscopy, and thermogravimetric analysis (TGA). In the presence of hydrogen peroxide, both dinuclear vanadium dioxido complexes were applied for the oxidation of a series of aromatic and aliphatic alkenes. High catalytic activity and efficiency were achieved using catalysts 1 and 2 in the oxidation of olefins. Alkenes with electron-donating groups make the oxidation processes easy. Thus, in general, aromatic olefins show better substrate conversion in comparison to the aliphatic olefins. Under optimized reaction conditions, both copper catalysts 3 and 4 fail to compete with the activity shown by their vanadium counterparts. Irrespective of olefins, metal (vanadium or copper) complexes of the ligand [salLH4] (I) show better substrate conversion(%) compared with the metal complexes of the ligand [NsalLH4] (II).
- Maurya, Abhishek,Haldar, Chanchal
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- g-C3N4/metal halide perovskite composites as photocatalysts for singlet oxygen generation processes for the preparation of various oxidized synthons
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g-C3N4/metal halide perovskite composites were prepared and used for the first time as photocatalysts forin situ1O2generation to perform hetero Diels-Alder, ene and oxidation reactions with suitable dienes and alkenes. The standardized methodology was made applicable to a variety of olefinic substrates. The scope of the method is finely illustrated and the reactions afforded desymmetrized hydroxy-ketone derivatives, unsaturated ketones and epoxides. Some limitations were also observed, especially in the case of the alkene oxidations, and poor chemoselectivity was somewhere observed in this work which is the first application of MHP-based composites forin situ1O2generation. The experimental protocol can be used as a platform to further expand the knowledge and applicability of MHPs to organic reactions, since perovskites offer a rich variety of tuning strategies which may be explored to improve reaction yields and selectivities.
- Corti, Marco,Chiara, Rossella,Romani, Lidia,Mannucci, Barbara,Malavasi, Lorenzo,Quadrelli, Paolo
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p. 2292 - 2298
(2021/04/12)
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- Samarium-based Grignard-type addition of organohalides to carbonyl compounds under catalysis of CuI
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Grignard-type additions were readily achieved under the mediation of CuI (10 mol%) and samarium (2 equiv.) by employing various organohalides,e.g.benzyl, aryl, heterocyclic and aliphatic halides (Cl, Br or I), and diverse carbonyl compounds (e.g.carbonic esters, carboxylic esters, acid anhydrides, acyl chlorides, ketones, aldehydes, propylene epoxides and formamides) to afford alcohols, ketones and aldehydes, respectively, with high efficiency and chemoselectivity, in which the organosamarium intermediate might be involved.
- Liu, Chen,Liu, Yongjun,Qi, Yan,Song, Bin,Wang, Liang,Xiao, Shuhuan
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supporting information
p. 6169 - 6172
(2021/06/30)
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- Radical induced disproportionation of alcohols assisted by iodide under acidic conditions
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The disproportionation of alcohols without an additional reductant and oxidant to simultaneously form alkanes and aldehydes/ketones represents an atom-economical transformation. However, only limited methodologies have been reported, and they suffer from a narrow substrate scope or harsh reaction conditions. Herein, we report that alcohol disproportionation can proceed with high efficiency catalyzed by iodide under acidic conditions. This method exhibits high functional group tolerance including aryl alcohol derivatives with both electron-withdrawing and electron-donating groups, furan ring alcohol derivatives, allyl alcohol derivatives, and dihydric alcohols. Under the optimized reaction conditions, a 49% yield of 5-methyl furfural and a 49% yield of 2,5-diformylfuran were obtained simultaneously from 5-hydroxymethylfurfural. An initial mechanistic study suggested that the hydrogen transfer during this redox disproportionation occurred through the inter-transformation of HI and I2. Radical intermediates were involved during this reaction.
- Huang, Yang,Jiang, Haiwei,Li, Teng,Peng, Yang,Rong, Nianxin,Shi, Hexian,Yang, Weiran
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supporting information
p. 8108 - 8115
(2021/10/29)
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- Study of the Features of the Reaction of Arylcyclopropanes with Nitrozonium Ethyl Sulfate or Nitrozonium Tetrafluoroborate
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Abstract: The reactions of diaryl-, aryl-, and alkyl–arylcyclopropanes with ethyl nitrite in the presence of sulfur trioxide and sulfur trioxide dioxane complex, as well as the reactions of 1-alkyl-2-arylcyclopropanes with NOBF4 were studied. It was found that the attack of the nitrosonium cation, accompanied by the formation of a benzyl carbocation, leads to the formation of isoxazolines. The introduction of bulky alkyl substituents into the cyclopropane ring changes the regioselectivity of nitrosation, favoring the attack of the electrophilic particle on the benzyl position and leading to the competitive formation of an alkyl carbocation. Depending on the structure of the alkyl substituent, both products of intramolecular heterocyclization accompanied by skeletal rearrangements and products formed with the participation of an external nucleophile are formed.
- Bondarenko, O. B.,Gavrilova, A. Yu.,Solodovnikova, T. A.,Tikhanushkina, V. N.,Zyk, N. V.
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p. 753 - 762
(2020/07/03)
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- A tunable synthesis of either benzaldehyde or benzoic acid through blue-violet LED irradiation using TBATB
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In this paper, a highly efficient, metal-free, and homogeneous method for the selective aerobic photooxidation of alcohols and photooxidative-desilylation of tert-butyldimethylsilyl ethers (TBDMS) in the presence of tetrabutylammonium tribromide (TBATB) under irradiation of visible light was reported. The light source: blue (460 nm) and violet (400 nm) LED, can control selective oxidation to aldehyde or carboxylic acid.
- Mardani, Atefeh,Heshami, Marouf,Shariati, Yadollah,Kazemi, Foad,Abdollahi Kakroudi, Mazaher,Kaboudin, Babak
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- One-pot, oxidative and selective conversion of benzylic silyl and tetrahydropyranyl ethers to gem-dichlorides using trichloroisocyanuric acid and triphenylphosphine as an efficient and neutral system
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A one-pot and oxidative method is described for the first time for the conversion of benzylic trimethylsilyl (TMS) and tetrahydropyranyl (THP) ethers to gem-dichlorides using trichloroisocyanuric acid (TCCA) and triphenylphosphine (PPh3) in neutral media. Various theses substrates containing electron withdrawing or donating groups can be efficiently converted to their corresponding gem-dichlorides in good to excellent yields. The present method shows a high degree of chemoselectivity, and due to its one-pot nature is in accordance with green chemistry.
- Khadem Moghaddam, Roqayeh,Aghapour, Ghasem
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p. 398 - 406
(2020/11/19)
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- Method for reducing carboxylic acid into aldehyde compounds
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The invention discloses a method for reducing carboxylic acid into aldehyde compounds, and belongs to the field of organic chemical synthesis. Specifically, in an argon atmosphere, a carboxylic acid compound, a transition metal nickel compound, an anhydride compound, a ligand and a reducing agent are dissolved in an organic solvent, the mixture is heated and subjected to stirring reaction, after the reaction is finished, the pressure is reduced to remove the organic solvent, column chromatography separation is performed, and various aldehyde compounds are obtained. The method has the advantages of simple synthesis steps, mild reaction conditions, simplicity and easiness in operation, realization of successful reduction of the carboxylic acid compound into the aldehyde organic compounds, small use amount of the reaction catalyst, high product yield, and provision of a new approach for reduction of the carboxylic acid compound into the aldehyde compounds. Compared with a conventional method, the method has the advantages that raw materials are cheap, easy to obtain and environmentally friendly, substrate universality and functional group compatibility are improved, and the method hascertain innovativeness and unique research significance in organic synthesis methodology.
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Paragraph 0059-0062
(2020/02/27)
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- A Strategy for Accessing Aldehydes via Palladium-Catalyzed C?O/C?N Bond Cleavage in the Presence of Hydrosilanes
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We report the catalytic reduction of both active esters and amides by selective C(acyl)?X (X=O, N) cleavage to access aldehyde functionality via a palladium-catalyzed strategy. Reactions are promoted by hydrosilanes as reducing reagents with good to excellent yields and with excellent chemoselectivity for C(acyl)?N and C(acyl)?O bond cleavage. Carboxylic acid C(acyl)?O bonds are activated by 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) to form triazine ester intermediates, which further react with hydrosilanes to yield aldehydes in one-pot two-step procedures. We demonstrate that C(acyl)?O cleavage/formylation offers higher yields and broader substrate scopes compared with C(acyl)?N cleavage under the same reaction conditions.
- He, Zhanyu,Liu, Tingting,Ru, Junxiang,Wang, Yulin,Wang, Zijia,Zeng, Zhuo
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p. 5794 - 5800
(2020/12/01)
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- Aqueous extract of Shikakai; a green solvent for deoximation reaction: Mechanistic approach from experimental to theoretical
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This article describes a green method for regeneration of carbonyl compounds from various types of oxime compounds under microwave radiation using I2 and aqueous saponin solution isolated from Shikakai. Effect of saponin concentration on yield percentage of regenerated different types of carbonyl compounds has been discussed. A correlation has been established between saponin concentration and yield percentage of carbonyl compounds. Mechanism of interaction between oxime and saponin is established on the basis of density functional theory. In addition, the quantum chemical parameters for saponin have been determined. Furthermore, electrostatic surface analysis of the saponin is carried out to confirm the mechanism of interaction between saponin and oximes.
- Das, Debadutta,Kudrat-E-Zahan, Md.,Mahal, Ahmed,Mohapatra, Ranjan K.,Parhi, Pankaj K.,Sahu, Raghaba,Sarangi, Ashish K.
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- Efficient selective oxidation of alcohols to carbonyl compounds catalyzed by Ru-terpyridine complexes with molecular oxygen
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The oxidation of alcohols with molecular oxygen is a promising approach to produce corresponding carbonyl compounds. In this work, efficient aerobic oxidation of alcohols to carbonyl compounds catalyzed by ruthenium-terpyridine [(tpy-PhCH3)RuCl3] with isobutyraldehyde as co-substrate was developed. Various alcohols including primary and secondary alcohols are smoothly converted to corresponding carbonyl compounds in good yield. In a 100 times large-scale oxidation of benzyl alcohol, benzaldehyde was obtained with 92% isolated yield. Moreover, a plausible mechanism involving high-valence ruthenium species was proposed based on in situ UV–vis spectroscopy.
- Han, Qi,Guo, Xiao-Xuan,Zhou, Xian-Tai,Ji, Hong-Bing
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- Catalytic Selective Oxidation of Primary and Secondary Alcohols Using Nonheme [Iron(III)(Pyridine-Containing Ligand)] Complexes
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The selective oxidation of different primary and secondary alcohols to carbonyl compounds by hydrogen peroxide was found to be catalyzed in conversion ranging from good to excellent by an iron(III) complex of a pyridine-containing macrocyclic ligand (Pc-L), without the need of any additive. The choice of the counteranion (Cl, Br, OTf) appeared to be of fundamental importance and the best results in terms of selectivity (up to 99 %) and conversion (up to 98 %) were obtained using the well-characterized [Fe(III)(Br)2(Pc-L)]Br complex, 4c. Magnetic moments in solid-state, also confirmed in solution ([D6]DMSO) by Evans NMR method, were calculated and point out to an iron metal center in the high spin state of 5/2. The crystal structure shows that the iron(III) center is coordinated by the four nitrogen atoms of the macrocycle and two bromide anions to form a distorted octahedral coordination environment. The catalytic oxidation of benzyl alcohol in acetonitrile was found occurring with better conversions and selectivities than in other solvents. The reaction proved to be quite general, tolerating aromatic and aliphatic alcohols, although very low yields were obtained for terminal aliphatic alcohols. Preliminary mechanistic studies are in agreement with a catalytic cycle promoted by a high-spin iron complex.
- Caselli, Alessandro,Gallo, Emma,Panza, Nicola,Rizzato, Silvia,Tseberlidis, Giorgio,di Biase, Armando
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supporting information
p. 6635 - 6644
(2020/10/30)
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- Chemoselective photocatalytic oxidation of alcohols to aldehydes and ketones by nitromethane on titanium dioxide under violet 400 nm LED light irradiation
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In this study, for the first time, nitroalkanes, especially nitromethane, have been used as electron acceptors for the highly chemoselective oxidation of alcohols in the presence of a TiO2 photocatalyst under 400 nm LED irradiation. The reactions showed excellent selectivity for the production of aldehydes. Interestingly, aldehydes such as benzaldehyde and p-methoxybenzaldehyde are stable under the reaction conditions. In the case of the use of 2-nitropropane and 2-methyl-2-nitropropane, the product imine, which is the result of the reaction of the aldehyde with aliphatic amine, is also obtained.
- Kaboudin, Babak,Kazemi, Foad,Rahimi Niaraki, Azam,Saraee, Mohammad Reza
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p. 2326 - 2330
(2020/04/03)
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- Boosting multiple photo-assisted and temperature controlled reactions with a single redox-switchable catalyst: Solvents as internal substrates and reducing agent
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An alternative and economically viable process for the synthesis of β-aryl enals, enones and the aryl amines has been developed by partial oxidation of ethanol, isopropanol and N, N-dimethyl formamide (DMF). The formation of β-aryl enals, enones and the aryl amines was catalyzed by a mixed metal oxides layer of cobalt and chromium supported on halloysite nanotubes, designated as CoCr2O4-HNT. The C[sbnd]C and C[sbnd]N bond formation reactions were found to be influenced by temperature and the nature of base. The condensation of aldehyde with in situ generated acetaldehyde by ethanol oxidation forming β-aryl enals occurred selectively at 120 °C. The partial oxidation of isopropanol to acetone and its condensation with aldehydes forming β-aryl enones occurred at room temperature. Increase in temperature caused the liberation of hydrogen gas from isopropanol and allowed the reversible reduction of aldehydes to alcohols. Increase in temperature in isopropanol and increase in base concentration in ethanol causes the selective reduction of aldehydes to alcohols. Besides being active for the Claisen-Schmidt type of reactions and the aryl halides amination process, the synthesized catalyst was also found to be highly active for the photocatalytic oxidation of benzyl alcohols in absence of any external oxidizing agent. The positive holes (h+) generated at the Co(II) site as evident from EPR analysis was considered to be responsible for high photocatalytic activity of the material reducing the recombination rate of holes and electrons (e?). Density Functional Theory calculations were performed to understand the mechanism of ethanol oxidation to acetaldehyde.
- Bania, Kusum K.,Baruah, Manash J.,Bhattacharyya, Pradip K.,Das, Biraj,Karunakar, Galla V.,Roy, Subhasish,Saikia, Lakshi,Saikia, Pinku,Sharma, Mukesh
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p. 104 - 121
(2020/06/01)
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- Iodine-catalyzed α,β-dehydrogenation of ketones and aldehydes generating conjugated enones and enals
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A transition metal-free α,β-dehydrogenation of ketones and aldehydes was developed. This reaction was conducted in a facile I2/KI/DMSO system to produce the corresponding unsaturated compounds in good to high yields. The gram-scale experiment also indicated the potential synthetic value of this new reaction in organic synthesis. In the reaction, DMSO acted as both solvent and mild oxidant.
- Cao, Yuanjie,Chen, Tieqiao,Huang, Tianzeng,Liu, Long
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supporting information
p. 8697 - 8701
(2020/06/08)
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- Highly Regio- A nd Enantioselective Hydrogenation of Conjugated α-Substituted Dienoic Acids
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Highly regio- A nd enantioselective hydrogenation of conjugated α-substituted dienoic acids was realized for the first time using Trifer-Rh complex, providing a straightforward method for the synthesis of chiral α-substituted ?,?′-unsaturated acids. DFT calculations revealed N+H-O hydrogen bonding interaction is formed to stabilize the transition state and the coordination of 4,5-double bond to Rh(III) center would facilitate the reductive elimination process. This hydrogenation provided a gram-scale synthesis of the precursor of sacubitril.
- Liu, Xian,Liu, Song,Wang, Quanjun,Zhou, Gang,Yao, Lin,Ouyang, Qin,Jiang, Ru,Lan, Yu,Chen, Weiping
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p. 3149 - 3154
(2020/04/09)
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- Copper-Catalyzed Aerobic Oxidation of Amines to Benzothiazoles via Cross Coupling of Amines and Arene Thiolation Sequence
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A one-pot three-component synthesis of benzothiazoles has been developed using the copper-catalyzed aerobic cross coupling of amines followed by arene thiolation using elemental sulfur. The dual roles of elemental sulfur and CuCl(OH)-TMEDA in the aerobic amine oxidation and the aniline thiolation enable the facile access to benzothiazole derivatives from readily available starting materials. The operational simplicity of the current promiscuous catalyst system suggests the high synthetic potential in the preparation of heterocyclic compounds. (Figure presented.).
- Kim, Jihyeon,Oh, Kyungsoo
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supporting information
p. 3576 - 3582
(2020/08/05)
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- Cobalt-catalysed selective synthesis of aldehydes and alcohols from esters
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Efficient and selective reduction of esters to aldehydes and alcohols is reported in which a simple cobalt pincer catalyst catalyses both transformations using diethylsilane as a reductant. Remarkably, the reaction selectivity is controlled by the stoichiometry of diethylsilane. This journal is
- Pattanaik, Sandip,Gunanathan, Chidambaram
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supporting information
p. 7345 - 7348
(2020/07/14)
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- Iodine/water-mediated deprotective oxidation of allylic ethers to access α,β-unsaturated ketones and aldehydes
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The first iodine/water-mediated deprotective oxidation of allylic ethers to access α,β-unsaturated ketones and aldehydes was achieved. The reaction tolerates a wide range of functionalities. Furthermore, this protocol was found to be applicable to the oxidative transformation of allylic acetates. The proposed mechanism involves an oxygen transfer from solvent water to the carbonyl products.
- Chen, Weifeng,Jiang, Kezhi,Xue, Yuntian,Yan, Yaolong,Yang, Lei
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p. 14720 - 14724
(2020/04/27)
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- C-H Functionalization of Amino Alcohols by Osmium Tetroxide/NMO or TPAP/NMO: Protecting Group-Free Synthesis of Indolizidines (–)-223AB and 3-epi-(–)-223AB
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The oxidative cyclization of amino alcohols by osmium tetroxide/NMO or tetrapropylammonium perruthenate (TPAP)/NMO was found to provide an N,O-acetal moiety through the trapping of the resulting iminium ion by the alcohol. These two transformations were demonstrated in the synthesis of indolizidines (–)-223AB and 3-epi-(–)-223AB.
- Chen, Wei-Lun,Wang, Lee-Ya,Li, Yu-Jang
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supporting information
p. 103 - 107
(2020/01/02)
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- Catalyst-Free Regioselective [3+2] Cycloadditions of α,β-unsaturated N-arylnitrones with Alkenes to Access Functionalized Isoxazolidines: A DFT Study
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The catalyst-free regioselective [3+2]-cycloaddition of α,β-unsaturated N-arylnitrones with alkenes are developed. The series of synthetically important functionalized isoxazolidines are prepared in good to excellent yields by step economic pathway under ligand and transition-metal-free conditions. The regioselective cycloaddition pathway supported by control experiment and computational study.
- Ghosh, Arnab,Mane, Manoj V.,Rode, Haridas B.,Patil, Siddappa A.,Sridhar, Balasubramanian,Dateer, Ramesh B.
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supporting information
p. 899 - 903
(2020/03/03)
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- A chemoselective photolabile protecting group for aldehydes
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A new and high-efficiency photolabile protecting group (PLPG) for aldehydes is described. The PLPG was introduced to aldehydes by using a Lewis acid. Results showed that the PLPG can be released rapidly and smoothly under ultraviolet (UV) irradiation with high efficiency and low cost. This PLPG can easily synthesized and also be selectively protect aldehydes in the presence of ketones.
- Peng, Tao,Wang, Gang,Wang, Lin,Wen, Xiaoxue,Xu, Jing,Xu, Kaijun,Yang, Hongpeng,Zhang, Shouguo
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supporting information
(2020/02/29)
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- Facile synthesis of a highly efficient Co/Cu@NC catalyst for base-free oxidation of alcohols to esters
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The direct oxidation of alcohols to esters is an environmentally benign and cost-effective organic synthetic strategy, but it is still a great challenge to discover an economic, highly active, and long-term stable catalyst for efficient transformation of alcohols to esters under milder conditions. Herein, we developed cobalt and copper nanoparticle -co-decorated nitrogen-doped carbon catalysts (CoCu@NCn) through two steps of ball milling and calcination. It was found that CoCu@NCn could catalyze the oxidation of alcohols to esters effectively in the absence of basic additives. The catalytic activity was much higher than those of monometallic Co@NC2 and Cu@NC2 samples, and the catalyst can be conveniently recovered and quite steadily reused. Through a series of control experiments and characterizations, it is concluded that the remarkable catalytic performance of CoCu@NC2 was associated with the synergistic effect between the two metal components, the enhanced basic active sites and the active surface area.
- Jiang, Jiusheng,Li, Xiang,Du, Shengyu,Shi, Langchen,Jiang, Pingping,Zhang, Pingbo,Dong, Yuming,Leng, Yan
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p. 7780 - 7785
(2020/06/09)
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- PdBr2-Catalyzed Acetal Formation of Carbonyl Compounds Using Diazophenanthrenequinone: Utility of 9,10-Phenanthrenedioxyacetal
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We developed a new acetalization method of ketones and aldehydes under non-acidic conditions using diazophenanthrenequinone and PdBr2. The formed acetals that have a phenanthrene skeleton withstand under mild acidic conditions. Removal of acetals was successfully proceeded under strong acidic or oxidation conditions using aqueous ceric ammonium nitrate (CAN) to afford corresponding ketones and aldehydes.
- Kitamura, Mitsuru,Fujimura, Ryo,Nishimura, Tomoaki,Takahashi, Shuhei,Shimooka, Hirokazu,Okauchi, Tatsuo
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supporting information
p. 5319 - 5322
(2020/06/10)
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- Biocatalytic reduction of α,β-unsaturated carboxylic acids to allylic alcohols
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We have developed robust in vivo and in vitro biocatalytic systems that enable reduction of α,β-unsaturated carboxylic acids to allylic alcohols and their saturated analogues. These compounds are prevalent scaffolds in many industrial chemicals and pharmaceuticals. A substrate profiling study of a carboxylic acid reductase (CAR) investigating unexplored substrate space, such as benzo-fused (hetero)aromatic carboxylic acids and α,β-unsaturated carboxylic acids, revealed broad substrate tolerance and provided information on the reactivity patterns of these substrates. E. coli cells expressing a heterologous CAR were employed as a multi-step hydrogenation catalyst to convert a variety of α,β-unsaturated carboxylic acids to the corresponding saturated primary alcohols, affording up to >99percent conversion. This was supported by the broad substrate scope of E. coli endogenous alcohol dehydrogenase (ADH), as well as the unexpected CC bond reducing activity of E. coli cells. In addition, a broad range of benzofused (hetero)aromatic carboxylic acids were converted to the corresponding primary alcohols by the recombinant E. coli cells. An alternative one-pot in vitro two-enzyme system, consisting of CAR and glucose dehydrogenase (GDH), demonstrates promiscuous carbonyl reductase activity of GDH towards a wide range of unsaturated aldehydes. Hence, coupling CAR with a GDH-driven NADP(H) recycling system provides access to a variety of (hetero)aromatic primary alcohols and allylic alcohols from the parent carboxylates, in up to >99percent conversion. To demonstrate the applicability of these systems in preparative synthesis, we performed 100 mg scale biotransformations for the preparation of indole-3-aldehyde and 3-(naphthalen-1-yl)propan-1-ol using the whole-cell system, and cinnamyl alcohol using the in vitro system, affording up to 85percent isolated yield.
- Aleku, Godwin A.,Leys, David,Roberts, George W.
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p. 3927 - 3939
(2020/07/09)
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- Biocatalytic Asymmetric Michael Additions of Nitromethane to α,β-Unsaturated Aldehydes via Enzyme-bound Iminium Ion Intermediates
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The enzyme 4-oxalocrotonate tautomerase (4-OT) exploits an N-terminal proline as main catalytic residue to facilitate several promiscuous C-C bond-forming reactions via enzyme-bound enamine intermediates. Here we show that the active site of this enzyme can give rise to further synthetically useful catalytic promiscuity. Specifically, the F50A mutant of 4-OT was found to efficiently promote asymmetric Michael additions of nitromethane to various α,β-unsaturated aldehydes to give γ-nitroaldehydes, important precursors to biologically active γ-aminobutyric acids. High conversions, high enantiocontrol, and good isolated product yields were achieved. The reactions likely proceed via iminium ion intermediates formed between the catalytic Pro-1 residue and the α,β-unsaturated aldehydes. In addition, a cascade of three 4-OT(F50A)-catalyzed reactions followed by an enzymatic oxidation step enables assembly of γ-nitrocarboxylic acids from three simple building blocks in one pot. Our results bridge organo- and biocatalysis, and they emphasize the potential of enzyme promiscuity for the preparation of important chiral synthons.
- Guo, Chao,Saifuddin, Mohammad,Saravanan, Thangavelu,Sharifi, Masih,Poelarends, Gerrit J.
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- Fe3O4@SiO2@Im[Cl]Mn(III)-complex as a highly efficient magnetically recoverable nanocatalyst for selective oxidation of alcohol to imine and oxime
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An efficient and environmentally friendly oxidation process for the one-pot preparation of oxime, imine and carbonyl compounds through alcohol oxidation in the presence of H2O2 and/or O2 have been developed by a melamine-Mn(III) Schiff base complex supported on Fe3O4@SiO2–Cl nanoparticles, named as Fe3O4@SiO2@Im[Cl]Mn(III)-complex nanocomposite, at room temperature. Direct oxidation of alcohol to carboxylic acid was performed using the catalyst in the presence of molecular O2 at room temperature in a different approach. The oxidation products were obtained with excellent yields and high TOFs. The properties of the catalyst were characterized by Fourier transform infrared spectroscopy (FTIR), elemental analysis (C, H, N), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), dynamic light scattering (DLS), energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), inductive coupled plasma (ICP), cyclic voltammetry (CV), nuclear magnetic resonance (1H & 13C NMR), vibration sample magnetometer (VSM), Brunauer– Emmett–Teller (BET) and differential pulse voltammetry (DPV) analyses. The mechanism of the oxidation processes was investigated for the both H2O2 and O2 oxidants. The role of the imidazolium moiety in the catalyst as a secondary functionality was investigated. Chemoselectivity behavior of the catalyst was studied by some combinations. The catalyst could be recycled from the reaction mixture by a simple external magnet and reused for several times without any considerable reactivity loss.
- Kazemnejadi, Milad,Alavi, Seyyedeh Ameneh,Rezazadeh, Zinat,Nasseri, Mohammad Ali,Allahresani, Ali,Esmaeilpour, Mohsen
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p. 230 - 249
(2019/03/28)
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- Random Mutagenesis-Driven Improvement of Carboxylate Reductase Activity using an Amino Benzamidoxime-Mediated High-Throughput Assay
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Carboxylic acid reductases (CARs) catalyze the direct adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide phosphate (NADPH) dependent reduction of carboxylic acids to their corresponding aldehydes. The identification and improvement of CARs by protein engineering is, however, severely limited by the lack of fast and generic methods to quantify aldehydes. Within this study, we applied a convenient high-throughput assay (HTA) based on amino benzamidoxime (ABAO) that allows the substrate-independent and chemoselective quantification of aldehydes. Random mutagenesis of the well-known CAR from Nocardia iowensis (CARNi) to improve its activity for sterically demanding 2-substituted benzoic acid derivatives was conducted in a KM-dependent fashion, and the HTA applied in the presence of microbial cells. The study identified a hot spot in the active site of CARNi that increased the affinity to 2-methoxybenzoic acid 9-fold upon mutation from glutamine to proline (Q283P). The catalytic performance of CARNiQ283P appeared to be significantly improved also for other substrates such as 2-substituted (2-Cl, 2-Br) as well as 3- and 4-substituted benzoic acids (3-OMe, 4-OMe), and even aliphatic octanoic acid. (Figure presented.).
- Schwendenwein, Daniel,Ressmann, Anna K.,Doerr, Mark,H?hne, Matthias,Bornscheuer, Uwe T.,Mihovilovic, Marko D.,Rudroff, Florian,Winkler, Margit
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supporting information
p. 2544 - 2549
(2019/04/26)
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- Nickel-Catalyzed Selective Reduction of Carboxylic Acids to Aldehydes
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The direct reduction of carboxylic acids to aldehydes is a fundamental transformation in organic synthesis. The combination of an air-stable Ni precatalyst, dimethyl dicarbonate as an activator, and silane reductant effects this reduction for a wide variety of substrates, including pharmaceutically relevant structures, in good yields and with no overreduction to alcohols. Moreover, this methodology is scalable, allows access to deuterated aldehydes, and is also compatible with one-pot utilization of the aldehyde products.
- Iosub, Andrei V.,Morav?ík, ?tefan,Wallentin, Carl-Johan,Bergman, Joakim
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supporting information
p. 7804 - 7808
(2019/10/14)
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- Organosuperbase dendron manganese complex grafted on magnetic nanoparticles; heterogeneous catalyst for green and selective oxidation of ethylbenzene, cyclohexene and oximes by molecular oxygen
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Magnetic Fe3O4 nanoparticles as a support were modified with an amino-terminated organosilicon and cyanoric choloride ligands. The novel manganese complex was grafted on modified magnetic support (Mn(II)-Met@MMNPs). The nanocatalyst structure, particle size, morphology and surface properties was well characterized by elemental analysis, ICP-AES, AAS, EDS, FT-IR, SEM, TEM, DLS, VSM, TGA, XRD and XPS. In order to develop an effective heterogeneous nanocatalyst for eco-friendly aerobic, highly active and selective catalytic reactions, synthesized nanocatalyst was applied in oxidation of various organic compounds. The catalytic performance of the manganese nanocatalyst in the aerobic oxidation of ethylbenzene (EB), cyclohexene (CYHE) and various aldoximes and ketoxime were studied. Selective aerobic oxidation of EB and CYHE and various oximes were catalyzed by the Mn-nanocatalyst using N-hydroxyphthalimide (NHPI) with molecular oxygen as the green oxidant without the need of any reducing agent, and respectively the acetophenone (AcPO) as a benzylic product, 2-cyclohexene-1-one (CYHE[dbnd]O) as an allylic product and corresponding carbonyl compounds were obtained. The oxidation process has been optimized for Mn-nanocatalyst by considering the effect of different parameters such as the ratio and amount of Mn-nanocatalyst/NHPI, reaction time and solvent for achieving maximum conversion and selectivity to products. Due to their significant low cost, informal preparation, easy magnetically separation from reaction mixture, excellent catalytic performance, simple recovery and reusability without any metal leaching, the Mn-nanocatalyst has huge application prospect in selective and green oxidation process.
- Faraji, Ali Reza,Ashouri, Fatemeh,Hekmatian, Zahra,Heydari, Somayyeh,Mosazadeh, Sima
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- The studies on chemoselective promiscuous activity of hydrolases on acylals transformations
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Chemoselective, mild and convenient protocol for the hydrolysis of the synthetically relevant acylals via promiscuous enzyme-catalyzed hydrolysis has been developed. It has been shown that promiscuous activity of the used hydrolases dominates their native activity related with carboxylic esters hydrolysis. The main advantage of the present methodology is that it can be conducted under neutral conditions at room temperature. Moreover, complete deprotection of acylals takes place within 10–20 min. Developed protocol can be used with compounds having a variety of hydrolytic labile groups since the cleavage is proceeded under neutral conditions and occurs exclusively on acylal moiety. Further this protocol was extended by the tandem Passerini multicomponent reaction leading to the α-acetoxy amides using acylals as the surrogates of the carbonyl components to P-MCR.
- Koszelewski, Dominik,Ostaszewski, Ryszard
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- Mechanistic insights into the microwave-assisted cinnamyl alcohol oxidation using supported iron and palladium catalysts
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The efficient oxidation of alcohols remains a challenge, especially when using solid heterogeneous catalysts. Herein, the catalytic activity of mechanochemically prepared iron and palladium particles on various supports are compared for the oxidation of c
- Wang, Yantao,Prinsen, Pepijn,Mangin, Floriane,Yepez, Alfonso,Pineda, Antonio,Rodríguez-Castellón, Enrique,Hasan Shah Gilani, Muhammad Rehan,Xu, Guobao,Len, Christophe,Luque, Rafael
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- Extended Open-Chain Polyenides as Versatile Delocalized Anion Ligands for Metal Chain Clusters
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Although small cyclic- and open-chain unsaturated hydrocarbon anions such as cyclopentadienide and open-chain pentadienide are used as the strongly electron-donating auxiliary ligands for metal complexes, more extended π-conjugated unsaturated hydrocarbon
- Yamashita, Mitsuki,Kawasumi, Yuna,Tachibana, Yuki,Horiuchi, Shinnosuke,Yamamoto, Koji,Murahashi, Tetsuro
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supporting information
p. 1212 - 1216
(2019/01/04)
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- FeVO4 decorated –SO3H functionalized polyaniline for direct conversion of sucrose to 2,5-diformylfuran & 5-ethoxymethylfurfural and selective oxidation reaction
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In this study, a multi-functional catalyst, FeVO4 supported –SO3H functionalized polyaniline is prepared. First FeVO4 supported polyaniline is prepared. Then the resultant material is sulfonated using chlorosulphonic acid to obtain FeVO4 supported –SO3H functionalized polyaniline. This multi-functional catalyst exhibits excellent activity in the synthesis of 5-hydroxymethylfurfural from sucrose and oxidation of a wide range of aromatic and aliphatic alcohols. Further, the catalyst exhibits very good activity in the one-pot direct conversion of sucrose/fructose to 2,5-diformylfuran (DFF) and 5-ethoxymethylfurfural (EMF). This catalytic process involves the economical sucrose as a reactant and economical multi-functional catalyst based on polyaniline. In this one-pot, two-step process, -SO3H functionalized polyaniline is used in the first step for the conversion of sucrose to 5-hydroxymethylfurfural (HMF) followed by selective oxidation of HMF to DFF using FeVO4 sites present in the multi-functional catalyst. Moreover, acidic sites present in the multi-functional catalyst are suitable for the conversion of sucrose/fructose/HMF to EMF. Furthermore, molecular oxygen (1 atmosphere, 10 ml/min) is used as an eco-friendly and economical oxidant for the selective oxidation of a wide range of aromatic and aliphatic alcohols to aldehydes. The multi-functional catalyst presented here has been easily separated and recycled that make the process sustainable and economical for commercial perspectives.
- Kumar, Abhinav,Srivastava, Rajendra
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- A method for the preparation of aldehydes
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The invention discloses a method for the preparation of ketone, relates to the field of organic synthesis. This invention adopts the organic solvent as a medium, cyclopropene [...] derivative as an active agent, activated DMSO oxidation [...] oxidation. The method of the invention is simple, easy to operate, rapid reaction rate, mild reaction, the reaction rate can be adjusted, more economic, to achieve industrial laid the foundation.
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Paragraph 0116; 0117
(2019/05/28)
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