- The Isotope Effects in the Reactions of Phenylcarbene with Alcoholic Matrices
-
Product analysis studies on the reaction of phenylcarbene in deuterated alcoholic matrices at 77 K revealed that isotope effect on O-H (D) insertion is very small while substantial isotope effect was observed for C-H (D) insertion.
- Tomioka, Hideo,Ozaki, Yasuji,Izawa, Yasuji
-
-
Read Online
- New concept for the preparation of potassium sodides: The use of hexane as a non-polar solvent
-
NaK alloy in contact with 15-crown-5 hexane solution became potassium sodide K+(15-crown-5)2Na-. After the evaporation of hexane the crystalline solid product was analyzed by X-ray diffraction and the lattice parameters were calculated. The potassium sodide thus obtained could be easily dissolved in tetrahydrofuran. A deep blue solution containing sodium anions and complexed potassium cations was formed with a very low concentration of solvated electrons, i.e. of the order of 10-7M. Potassium anions were not detected in this case. A new crystalline potassium sodide K+(DCH-24-crown-8)2Na- was obtained using NaK alloy and dicyclohexano-24-crown-8 hexane solution.
- Grobelny, Zbigniew,Stolarzewicz, Andrzej,Morejko-Buz, Barbara,Winiarski, Antoni
-
-
Read Online
- Regiochemical control of the ring-opening of aziridines by means of chelating processes. Part 4: Regioselectivity of the opening reactions with MeOH of 1-(benzyloxy)-2,3- and -3,4-N-(methoxycarbonyl)aziridoalkanes under condensed and gas-phase operating conditions
-
The regioselectivity of the addition reaction of MeOH both in the condensed phase (MeOH/H2SO4) and in the gas-phase (MeOH/D3+) was examined in a series of activated aziridines. The results indicate that gas-phase operating conditions are particularly favorable for the occurrence of D+-mediated chelated bidentate species, which influence the regioselectivity of the opening process. In the condensed phase, the?chelating MeOH/LiClO4 protocol turned out to be decidedly less effective for regioselectivity and also in determining the composition of the reaction mixture.
- Crotti, Paolo,Renzi, Gabriele,Roselli, Graziella,Di Bussolo, Valeria,Giuli, Sandra,Tsitsigia, Sofia,Romano, Maria Rosaria
-
-
Read Online
- Oxoammonium-Mediated Allylsilane–Ether Coupling Reaction
-
A new C(sp3)?H functionalization reaction consisting of the oxidative α-allylation of allyl- and benzyl- methyl ethers has been developed. The C?C coupling could be carried out under mild conditions thanks to the use of cheap and green oxoammonium salts. The scope of the reaction was studied over 27 examples, considering the nature of the substituents on the two coupling partners.
- Carlet, Federica,Bertarini, Greta,Broggini, Gianluigi,Pradal, Alexandre,Poli, Giovanni
-
supporting information
p. 2162 - 2168
(2021/04/02)
-
- Co2(CO)8-catalyzed reactions of acetals or lactones with hydrosilanes and carbon monoxide. A new access to the preparation of 1,2-diol derivatives through siloxymethylation
-
The Co2(CO)8-catalyzed reaction of acetals with hydrosilanes and CO under mild reaction conditions (an ambient temperature under an ambient CO pressure), leading to the production of vicinal diols is reported. A siloxymethyl group can be introduced via the cleavage of one of two alkoxy groups in the acetal. The effects of the types of hydrosilanes, acetals, solvents, and reaction temperatures on the yield of siloxymethylation products were examined in detail. The reactivity for hydrosilanes is as follows; HSiMe3 > HSiEtMe2 > HSiEt2Me > HSiEt3. Hemiacetal esters are more reactive than dimethyl acetals. The polarity of the solvent used also has a significant effect on both the course of the reaction as well as the reaction rate. The site-selective siloxymethylation can be achieved in the case of cyclic acetals such as tetrahydrofuran (THF) and tetrahydropyrane (THP) derivatives, depending on the nature of the oxygen substituent attached adjacent to the oxygen atom in the ring. When 2-alkoxy THF or THP derivatives are used as substrates, the siloxymethylation takes place with cleavage of the ring C-O bond. In contrast, the reaction of 2-acetoxy THF or THP derivatives results in siloxymethylation with the cleavage of C-OAc bond. The ring-opening siloxymethylation of lactones was also examined.
- Chatani, Naoto,Fujii, Satoru,Kido, Yoichi,Nakayama, Yasuhide,Kajikawa, Yasuteru,Tokuhisa, Hideo,Fukumoto, Yoshiya,Murai, Shinji
-
-
- Solvolysis of benzyl phenyl ether in high-temperature aqueous methanol solution under high-pressure carbon dioxide
-
Alcoholysis of benzyl phenyl ether to various aromatic compounds was studied in high-temperature aqueous methanol solution under high-pressure carbon dioxide conditions. The products formed included benzyl methyl ether, benzyl alcohol, phenol and toluene. As high as 70.7 ± 0.2% yield of monocyclic aromatic hydrocarbon with 16.1 ± 0.3% yield of benzyl methyl ether was obtained by treating benzyl phenyl ether with an aqueous solution with 0.2 molar fraction of methanol, under 17.7 MPa carbon dioxide for 1 h at 573 K.
- Taniguchi, Kenkichi,Nanao, Hidetaka,Sato, Osamu,Yamaguchi, Aritomo,Shirai, Masayuki
-
p. 1658 - 1664
(2021/03/09)
-
- Selective catalytic degradation of a lignin model compound into phenol over transition metal sulfates
-
Transition metal salts were employed as the catalysts to improve the selective degradation of the α-O-4 lignin model compound (benzyl phenyl ether (BPE)) in the solvothermal system. The results concluded that most of the transition metal salts could enhan
- Wu, Min-Ya,Lin, Jian-Tao,Xu, Zhuang-Qin,Hua, Tian-Ci,Lv, Yuan-Cai,Liu, Yi-Fan,Pei, Rui-Han,Wu, Qiong,Liu, Ming-Hua
-
p. 3013 - 3019
(2020/02/03)
-
- Regulating Aromatic Alcohols Distributions by Cofeeding Methanol with Ethanol over Cobalt-Hydroxyapatite Catalyst
-
Aromatic alcohols, often used for the synthesis of plasticizers, coatings and pharmaceuticals, are currently produced from the oxidation of petroleum-derived aromatic hydrocarbons. Herein, we report a non-petroleum and environmentally friendly route for the production of aromatic alcohols: cofeeding methanol with ethanol over cobalt-hydroxyapatite catalyst, in which the distribution of aromatic alcohols products can be regulated by varying methanol pressure. Co species on hydroxyapatite can activate both methanol and ethanol to yield their corresponding aldehydes (formaldehyde and acetaldehyde). The followed cross- and self-condensations of aldehydes are catalyzed by hydroxyapatite to produce acrolein and 2-butenal, which are the key intermediates for the formation of aromatic oxygenates. The sequential cross-condensation and dehydrocyclization of acrolein and 2-butenal yield benzaldehyde, which is then hydrogenated to benzyl alcohol. The direct production of benzyl alcohol from methanol and ethanol could be regarded as a cutting-edge example, which ensures a promising route for sustainable aromatic alcohols production.
- He, Lei,Li, Wen-Cui,Lu, An-Hui,Wang, Qing-Nan,Weng, Xue-Fei,Zhou, Bai-Chuan
-
-
- Cleavage of aryl-ether bonds in lignin model compounds using a Co-Zn-beta catalyst
-
Efficient cleavage of aryl-ether linkages is a key strategy for generating aromatic chemicals and fuels from lignin. Currently, a popular method to depolymerize native/technical lignin employs a combination of Lewis acid and hydrogenation metal. However, a clear mechanistic understanding of the process is lacking. Thus, a more thorough understanding of the mechanism of lignin depolymerization in this system is essential. Herein, we propose a detailed mechanistic study conducted with lignin model compounds (LMC) via a synergistic Co-Zn/Off-Al H-beta catalyst that mirrors the hydrogenolysis process of lignin. The results suggest that the main reaction paths for the phenolic dimers exhibiting α-O-4 and β-O-4 ether linkages are the cleavage of aryl-ether linkages. Particularly, the conversion was readily completed using a Co-Zn/Off-Al H-beta catalyst, but 40% of α-O-4 was converted and β-O-4 did not react in the absence of a catalyst under the same conditions. In addition, it was found that the presence of hydroxyl groups on the side chain, commonly found in native lignin, greatly promotes the cleavage of aryl-ether linkages activated by Zn Lewis acid, which was attributed to the adsorption between Zn and the hydroxyl group. Followed by the cobalt catalyzed hydrogenation reaction, the phenolic dimers are degraded into monomers that maintain aromaticity. This journal is
- Chang, Hou-Min,Dou, Xiaomeng,Jameel, Hasan,Jiang, Xiao,Li, Wenzhi,Zhu, Chaofeng
-
p. 43599 - 43606
(2020/12/25)
-
- Hypercoordinated organotin(IV) compounds containing C,O- and C,N- chelating ligands: Synthesis, characterisation, DFT studies and polymerization behaviour
-
A series of 2-methoxymethyl tetraorganotins [2-(MeOCH2)C6H4]SnR3 (21: R = Ph; 22: R = n-Bu; 23: R = Me), diorganotin chlorides [2-(MeOCH2)C6H4]R2SnCl (24: R = Ph; 25a, 25b: R = n-Bu), monoorganotin dichlorides [2-(MeOCH2)C6H4]RSnCl2 (26: R = Ph; 27: R = n-Bu; 28: R = Me) and the tin trichloride [2-(MeOCH2)C6H4]SnCl3 (29) were successfully prepared from the reaction of the organolithium, [2-(MeOCH2)C6H4]Li, and the appropriate chlorostannane. Similarly, a series of dimethylamino stannanes including the tetraorganotin [2-(Me2NCH2)C6H4]SnPh3 (30), the diorganotin halides [2-(Me2NCH2)C6H4]Ph2SnX (34: X = Cl; 35: X = Br), dichlorides [2-(Me2NCH2)C6H4]RSnCl2 (38: R = Ph; 39: R = n-Bu; 40: R = Me) and the tribromide [2-(Me2NCH2)C6H4]SnBr3 (37) were prepared by reaction of the appropriate organochlorostannane and the organolithium [2-(Me2NCH2)C6H4]Li followed by selective halogenations in the case of 34–37. 2-Methoxymethyl and dimethylamino diorganotin dichlorides (27, 28 and 39, 40) were hydrogenated with LiAlH4 to produce new 2-methoxymethyl [2-(MeOCH2)C6H4]RSnH2 (41: R = n-Bu; 42: R = Me) and dimethylamino [2-(Me2NCH2)C6H4]RSnH2 (44: R = n-Bu; 45: R = Me) dihydrides. X-ray structure determination of 30 revealed a nearly tetrahedral stannane, while structural analysis of 24, 29 and 40 display distorted trigonal bipyramidal geometry at Sn with Cl trans to the datively coordinated heteroatom. A selection of DFT methods were assessed for accuracy in predicting the solid-state geometries of the hypercoordinate Sn complexes. Catalytic dehydrocoupling of C,O- (41) and C,N- (44) diorganotin dihydrides was explored using Wilkinson's catalyst at RT leading to the recovery of modest molecular weight polymers (52: Mw = 3.03 × 104 Da, PDI = 1.4, 53: Mw = 3.1 × 104 Da, PDI = 1.86). The new rigid polymers were isolated in moderate (52: 65%) and low yields (53: 18%) and were found to be amorphous by DSC.
- Khan, Aman,Pau, Jeffrey,Loungxay, Julie,Magobenny, Timbila,Wylie, R. Stephen,Lough, Alan J.,Foucher, Daniel
-
supporting information
(2019/09/12)
-
- Aerobic C(sp2)-H Hydroxylations of 2-Aryloxazolines: Fast Access to Excited-State Intramolecular Proton Transfer (ESIPT)-Based Luminophores
-
The direct hydroxylation of 2-aryloxazolines via a deprotonative magnesiation using TMPMgCl·LiCl and subsequent oxidation with molecular oxygen or air as a green oxidant is reported. This method proceeds under mild conditions at room temperature with high regioselectivity and chemoselectivity. The obtained phenols exhibit tunable luminescence properties, induced by excited-state intramolecular proton transfer. This method opens a new opportunity for the sustainable synthesis of luminescent organic molecules.
- G?bel, Dominik,Clamor, Nils,Lork, Enno,Nachtsheim, Boris J.
-
supporting information
p. 5373 - 5377
(2019/06/07)
-
- Room-Temperature Benzylic Alkylation of Benzylic Carbonates: Improvement of Palladium Catalyst and Mechanistic Study
-
The palladium catalyst for the nucleophilic substitution of benzyl carbonates was improved by using 1,1′-bis(diisopropylphosphino)ferrocene (DiPrPF) as the ligand. The [Pd(η3-C3H5)(cod)]BF4-DiPrPF catalyst allows the benzylic substitution with soft carbanions to proceed even at 30 °C, affording the desired products in high yields (up to 99% yield). Thermally unstable pyridylmethyl esters are employable as the electrophilic substrates for the benzylic alkylation with the improved catalyst. Furthermore, we investigated the mechanism of the catalytic benzylic alkylation by means of DiPrPF ligand. The palladium(0) complex bearing DiPrPF activates the benzylic C-O bond to form the (benzyl)palladium(II) intermediate at room temperature. The coordination mode of the benzyl ligand would be equilibrium between the η1- and η3-manner. The nucleophile would preferentially react with the η3-benzyl ligand to give the desired product.
- Kuwano, Ryoichi,Yokogi, Masashi,Sakai, Ken,Masaoka, Shigeyuki,Miura, Takashi,Won, Sungyong
-
p. 1568 - 1579
(2019/09/04)
-
- Hydrosilylation of carbonyl and carboxyl groups catalysed by Mn(i) complexes bearing triazole ligands
-
Manganese(i) complexes bearing triazole ligands are reported as catalysts for the hydrosilylation of carbonyl and carboxyl compounds. The desired reaction proceeds readily at 80 °C within 3 hours at catalyst loadings as low as 0.25 to 1 mol%. Hence, good to excellent yields of alcohols could be obtained for a wide range of substrates including ketones, esters, and carboxylic acids illustrating the versatility of the metal/ligand combination.
- Martínez-Ferraté, Oriol,Chatterjee, Basujit,Werlé, Christophe,Leitner, Walter
-
p. 6370 - 6378
(2019/11/20)
-
- Deuterated Aryl Alkyl Ethers Synthesis via Nucleophilic Etherification of Aryl Alkyl Ethers and Thioethers with Deuterated Alcohols
-
A transition-metal-free etherification protocol that is capable of synthesizing deuterated ethers is described. A wide range of aryl alkyl ethers and thioethers were suitable for this transformation owing to the mild reaction conditions. Besides, a series of sterically bulky deuterated alcohols were successfully incorporated into cyano-substituted arenes. The results of mechanistic studies suggested this reaction might take place via nucleophilic aromatic substitution pathway.
- Li, Shuai,Wang, Xia,Wang, Xue-Qiang,Yang, Xin-Ge,Yu, Gui-Quan
-
p. 1805 - 1809
(2019/09/09)
-
- Methoxymethylation and benzyloxymethylation of aryl bromides
-
The methoxymethylation and benzyloxymethylation of aryl bromides methodology was reported here. The transition metal free, high yielding one pot procedure will be useful for synthetic community.
- Panda, Biswajit
-
p. 981 - 985
(2020/06/26)
-
- Synthesis of Benzyl Alkyl Ethers by Intermolecular Dehydration of Benzyl Alcohol with Aliphatic Alcohols under the Effect of Copper Containing Catalysts
-
Synthesis of benzyl alkyl ethers was performed in high yields by intermolecular dehydration of benzyl and primary, secondary, tertiary alcohols under the effect of copper containing catalysts. The formation of benzyl alkyl ethers occurs with participation of benzyl cation.
- Bayguzina,Gimaletdinova,Khusnutdinov
-
p. 1148 - 1155
(2018/10/24)
-
- Selective catalytic tailoring of the H unit in herbaceous lignin for methyl: P -hydroxycinnamate production over metal-based ionic liquids
-
Selective valorization of lignin to achieve high value and commodity chemicals is attracting increasing attention. In this work, an efficient and reusable metal-based ionic liquid (MBIL) was developed for the selective tailoring of p-coumaric acid ester (pCA), a typical p-hydroxyphenyl (H) unit, into methyl p-hydroxycinnamate (MPC). Under optimized conditions and in the presence of catalyst [Bmim][FeCl4], a volatile aromatic product of 10.5 wt% was obtained, of which, 70.5% separated as pure MPC with an isolated yield of 71.1 mg g-1. FT-IR, 13C NMR, ANO and 2D HSQC demonstrated that the H unit was preferentially tailored from lignin, of which, 86.0 wt% of the H structure unit is cut off from lignin, with 70.6% being selectively converted to MPC. Further investigation demonstrated that MBIL prefers to tailor ester bonds compared to ether bonds using model compounds, and the superior catalytic ester bond cleavage performance exhibited by [Bmim][FeCl4] can be ascribed to the relatively narrow energy gap between the lignin ester bond and [FeCl4]- anion and to the comparatively low absolute binding energy between the cation and anion through DFT calculations.
- Li, Zhangmin,Cai, Zhenping,Zeng, Qiang,Zhang, Tian,France, Liam John,Song, Changhua,Zhang, Yaqin,He, Hongyan,Jiang, Lilong,Long, Jinxing,Li, Xuehui
-
p. 3743 - 3752
(2018/08/21)
-
- Production of monocyclic phenols by the liquid-phase hydrogenolysis of benzofuran and dibenzyl ether using in situ hydrogen production from methanol
-
We herein report our study into the hydrogenolysis of benzofuran, a model compound for the poorly decomposable compounds derived from lignin, over Pt supported catalysts in methanol in the absence of gaseous hydrogen. In this in situ hydrogenolysis reaction system, it was elucidated that both hydrogen production from methanol and selective hydrogenolysis of the furan moiety proceeded simultaneously to yield monophenolic compounds and gaseous hydrogen. This in situ hydrogenolysis reaction was investigated at temperatures between 180 and 220 °C and with reaction times ranging from 1 to 48 h. We found that the hydrogenolysis reaction was accelerated with increased hydrogen concentrations in the solvent. The molar ratio of consumed hydrogen to net hydrogen production increased gradually upon increasing the reaction temperature and time. In addition, the in situ hydrogenolysis of benzofuran under a hydrogen gas atmosphere revealed that the hydrogen produced in situ was more effective in the reaction than gaseous hydrogen, likely due to the dissolution and diffusion resistances of the solvent. Furthermore, dibenzyl ether was hydrogenolyzed to give monocyclic aromatic compounds under the same reaction conditions, suggesting that this in situ hydrogenolysis process could be effective in converting the by-products obtained during lignin depolymerization into valuable aromatic compounds.
- Fujitsuka, Hiroyasu,Tamura, Masaki,Tago, Teruoki
-
p. 213 - 218
(2017/09/06)
-
- Air-Stable Blue Phosphorescent Tetradentate Platinum(II) Complexes as Strong Photo-Reductant
-
Strong photo-reductants have applications in photo-redox organic synthesis involving reductive activation of C?X(halide) and C=O bonds. We report herein air-stable PtII complexes supported by tetradentate bis(phenolate-NHC) ligands having peripheral electron-donating N-carbazolyl groups. Photo-physical, electrochemical, and computational studies reveal that the presence of N-carbazolyl groups enhances the light absorption and redox reversibility because of its involvement into the frontier MOs in both ground and excited states, making the complexes robust strong photo-reductant with E([Pt]+/*) over ?2.6 V vs. Cp2Fe+/0. The one-electron reduced [Pt]? species are stronger reductants with EPC([Pt]0/?) up to ?3.1 V vs. Cp2Fe+/0. By virtue of the strong reducing nature of these species generated upon light excitation, they can be used in light-driven reductive coupling of carbonyl compounds and reductive debromination of a wide range of unactivated aryl bromides.
- Li, Kai,Wan, Qingyun,Yang, Chen,Chang, Xiao-Yong,Low, Kam-Hung,Che, Chi-Ming
-
supporting information
p. 14129 - 14133
(2018/10/15)
-
- Auto-Tandem Catalysis with Frustrated Lewis Pairs for Reductive Etherification of Aldehydes and Ketones
-
Herein we report that a single frustrated Lewis pair (FLP) catalyst can promote the reductive etherification of aldehydes and ketones. The reaction does not require an exogenous acid catalyst, but the combined action of FLP on H2, R-OH or H2O generates the required Br?nsted acid in a reversible, “turn on” manner. The method is not only a complementary metal-free reductive etherification, but also a niche procedure for ethers that would be either synthetically inconvenient or even intractable to access by alternative synthetic protocols.
- Bakos, Mária,Gy?m?re, ádám,Domján, Attila,Soós, Tibor
-
supporting information
p. 5217 - 5221
(2017/04/27)
-
- Promoting Lignin Depolymerization and Restraining the Condensation via an Oxidation-Hydrogenation Strategy
-
For lignin valorization, simultaneously achieving the efficient cleavage of ether bonds and restraining the condensation of the formed fragments represents a challenge thus far. Herein, we report a two-step oxidation-hydrogenation strategy to achieve this goal. In the oxidation step, the O2/NaNO2/DDQ/NHPI system selectively oxidizes CαH-OH to Cα=O within the β-O-4 structure. In the subsequent hydrogenation step, the α-O-4 and the preoxidized β-O-4 structures are further hydrogenated over a NiMo sulfide catalyst, leading to the cleavage of Cβ-OPh and Cα-OPh bonds. Besides the transformation of lignin model compounds, the yield of phenolic monomers from birch wood is up to 32% by using this two-step strategy. The preoxidation of CαH-OH to Cα=O not only weakens the Cβ-OPh ether bond but also avoids the condensation reactions caused by the presence of Cα+ from dehydroxylation of CαH-OH. Furthermore, the NiMo sulfide prefers to catalyze the hydrogenative cleavage of the Cβ-OPh bond connecting with a Cα=O rather than catalyze the hydrogenation of Cα=O back to the original CαH-OH, which further ensures and utilizes the advantages of preoxidation.
- Zhang, Chaofeng,Li, Hongji,Lu, Jianmin,Zhang, Xiaochen,Macarthur, Katherine E.,Heggen, Marc,Wang, Feng
-
p. 3419 - 3429
(2017/06/09)
-
- Singlet vs Triplet Reactivity of Photogenerated α,n-Didehydrotoluenes
-
The reactivity of α,n-didehydrotoluenes (DHTs) in protic media (organic/aqueous mixtures) was explored by means of a combined computational and experimental approach. These intermediates were generated via a photoinduced double elimination process occurring in (chlorobenzyl)trimethylsilanes and led to the formation of a varied products distribution, depending on the isomer tested. Irradiation of ortho- and para-derivatives resulted, respectively, in the formation of triplet α,2- and α,4-DHTs, whose diradical reactivity led to both radical and polar products. On the other hand, irradiation of the meta-precursor led to the singlet α,3-DHT isomer. The latter showed a marked preference for the formation of polar products and this was rationalized, as supported by computational evidence, via the involvement of a zwitterionic species arising through interaction of the nucleophilic solvent with the benzylic position of the DHT.
- Pedroli, Chiara,Ravelli, Davide,Protti, Stefano,Albini, Angelo,Fagnoni, Maurizio
-
p. 6592 - 6603
(2017/07/15)
-
- π-Conjugated Triazenes: Intermediates That Undergo Oxidation and Substitution Reactions
-
Novel reactivity for π-conjugated triazenes is herein reported. This observed and unprecedented triazene reactivity gave access to oxidation and substitution reactions. These transformations include successful synthesis of aldehydes, ketones, ethers, and sulfides from readily available organic azides via π-conjugated triazene intermediates. Notably, the afforded adducts were obtained in good yields, at room temperature, and in the absence of added metal catalysts.
- Barragan, Enrique,Bugarin, Alejandro
-
p. 1499 - 1506
(2017/02/10)
-
- Method for preparing epoxy propane from ethylbenzene hydroperoxide and propylene
-
The invention relates to a method for preparing epoxy propane from ethylbenzene hydroperoxide and propylene, and is used for mainly solving the problems in the prior art that reaction temperature rising is higher and higher molar ratio of propylene to ethylbenzene hydroperoxide is needed for maintaining higher reaction efficiency. The problems are better solved through adopting the technical schemes that raw materials of ethylbenzene hydroperoxide and liquid propylene go into a multistage adiabatic reactor, and under conditions of the reaction temperature of 15-160 DEG C, the pressure of 1.0-12.0 MPa and the total molar ratio of propylene to ethylbenzene hydroperoxide of 1-20, the raw materials make contact with a Ti-silica catalyst and subjected to an epoxidation reaction to generate epoxy propane, wherein the raw material ethylbenzene hydroperoxide goes into catalyst bed layers of the multistage adiabatic reactor in a sectionalized manner, and a part of epoxidation reaction products containing epoxy propane circulate to an inlet of the reactor. The method can be used in industrial production of preparation of epoxy propane through epoxidation of ethylbenzene hydroperoxide and propylene.
- -
-
Paragraph 0034; 0035
(2017/03/22)
-
- Lewis acid promoted ruthenium(II)-catalyzed etherifications by selective hydrogenation of carboxylic acids/esters
-
Ethers are of fundamental importance in organic chemistry and they are an integral part of valuable flavors, fragrances, and numerous bioactive compounds. In general, the reduction of esters constitutes the most straightforward preparation of ethers. Unfortunately, this transformation requires large amounts of metal hydrides. Presented herein is a bifunctional catalyst system, consisting of Ru/phosphine complex and aluminum triflate, which allows selective synthesis of ethers by hydrogenation of esters or carboxylic acids. Different lactones were reduced in good yields to the desired products. Even challenging aromatic and aliphatic esters were reduced to the desired products. Notably, the in situ formed catalyst can be reused several times without any significant loss of activity. An assist from Al: A bifunctional catalyst system consisting of a Ru/phosphine complex and aluminum triflate allows selective hydrogenation of esters to ethers. A variety of lactones were reduced to the desired products in good yields. The catalyst further provides a general method for the reduction of linear esters and reductive etherification of carboxylic acids with alcohols.
- Li, Yuehui,Topf, Christoph,Cui, Xinjiang,Junge, Kathrin,Beller, Matthias
-
supporting information
p. 5196 - 5200
(2015/04/27)
-
- Photogenerated α,n-didehydrotoluenes from chlorophenylacetic acids at physiological pH
-
Aromatic diradicals are recognized as promising intermediates for DNA cleavage, but their formation has thus far been limited to the Bergman and Myers-Saito cycloaromatizations. We report here the phototriggered generation of all isomers of the potential DNA-cleaving α,n-didehydrotoluene diradicals at physiological pH, accomplished by the irradiation of chlorophenylacetic acids under mild conditions. The desired diradicals were formed upon photolysis of the chosen aromatic in aqueous phosphate buffer solution (pH = 7.3), with the consecutive elimination of biologically compatible chloride ion and carbon dioxide. Theoretical simulations reveal that the efficient decarboxylation of the primarily generated phenyl cations involves a previously not known diradical structure.
- Ravelli, Davide,Protti, Stefano,Fagnoni, Maurizio
-
supporting information
p. 852 - 858
(2015/03/05)
-
- Selective O-methylation of phenols and benzyl alcohols in simple pyridinium based ionic liquids
-
Synthesis of pyridinium based ionic liquids were reported and applied as catalyst for the selective O-methylation of phenols and benzyl alcohols. The reactions were carried out by using dimethylcarbonate (DMC) as the methylating agent. High selectivity, high yield and recyclability of the ionic liquids are important features of the reactions.
- Das, Pranab Jyoti,Das, Jupitara
-
-
- Photocatalytic decarboxylative reduction of carboxylic acids and its application in asymmetric synthesis
-
The decarboxylative reduction of naturally abundant carboxylic acids such as α-amino acids and α-hydroxy acids has been achieved via visible-light photoredox catalysis. By using an organocatalytic photoredox system, this method offers a mild and rapid entry to a variety of high-value compounds including medicinally relevant scaffolds. Regioselective decarboxylation is achieved when differently substituted dicarboxylic acids are employed. The application of this method to the synthesis of enantioenriched 1-aryl-2,2,2-trifluoroethyl chiral amines starting from natural α-amino acids further testifies to the utility of the developed photocatalytic decarboxylative reduction protocol.
- Cassani, Carlo,Bergonzini, Giulia,Wallentin, Carl-Johan
-
supporting information
p. 4228 - 4231
(2014/09/30)
-
- Eco-efficient preparation of a N-doped graphene equivalent and its application to metal free selective oxidation reaction
-
Here, we demonstrate that graphene oxide (GO) can be converted to N-doped reduced GO (rGO) that could become a substitute for N-doped graphene. Simultaneous doping and reduction can be accomplished for this purpose by simply mixing GO with hydrazine and then continuously sonicating the solution at 65 °C. A high level of reduction is realized, as evidenced by a carbon to oxygen ratio of 20.7 that compares with the highest value of 15.3 ever reported in solution (water + hydrazine) methods. Nitrogen doping is possible up to 6.3 wt% and the extent of doping can be increased with increasing sonication time. Notably, the simple tuning process of N-doping in GO greatly enhanced the efficiency of the carbocatalyst for various kinds of metal free oxidation reactions and hence is proposed as a suitable candidate for future industrial applications. This journal is the Partner Organisations 2014.
- Singh, Ajay K.,Basavaraju,Sharma, Siddharth,Jang, Seungwook,Park, Chan Pil,Kim, Dong-Pyo
-
supporting information
p. 3024 - 3030
(2014/06/10)
-
- Highly versatile catalytic hydrogenation of carboxylic and carbonic acid derivatives using a Ru-triphos complex: Molecular control over selectivity and substrate scope
-
The complex [Ru(Triphos)(TMM)] (Triphos = 1,1,1-tris(diphenylphosphinomethyl)ethane, TMM = trimethylene methane) provides an efficient catalytic system for the hydrogenation of a broad range of challenging functionalities encompassing carboxylic esters, amides, carboxylic acids, carbonates, and urea derivatives. The key control factor for this unique substrate scope results from selective activation to generate either the neutral species [Ru(Triphos)-(Solvent)H2] or the cationic intermediate [Ru(Triphos)-(Solvent)(H)(H2)]+ in the presence of an acid additive. Multinuclear NMR spectroscopic studies demonstrated together with DFT investigations that the neutral species generally provides lower energy pathways for the multistep reduction cascades comprising hydrogen transfer to C=O groups and C-O bond cleavage. Carboxylic esters, lactones, anhydrides, secondary amides, and carboxylic acids were hydrogenated in good to excellent yields under these conditions. The formation of the catalytically inactive complexes [Ru(Triphos)(CO)H2] and [Ru(Triphos)(μ-H)]2 was identified as major deactivation pathways. The former complex results from substrate-dependent decarbonylation and constitutes a major limitation for the substrate scope under the neutral conditions. The deactivation via the carbonyl complex can be suppressed by addition of catalytic amounts of acids comprising non-coordinating anions such as HNTf2 (bis(trifluoromethane)sulfonimide). Although the corresponding cationic cycle shows higher overall barriers of activation, it provides a powerful hydrogenation pathway at elevated temperatures, enabling the selective reduction of primary amides, carbonates, and ureas in high yields. Thus, the complex [Ru(Triphos)(TMM)] provides a unique platform for the rational selection of reaction conditions for the selective hydrogenation of challenging functional groups and opens novel synthetic pathways for the utilization of renewable carbon sources.
- Vom Stein, Thorsten,Meuresch, Markus,Limper, Dominik,Schmitz, Marc,H?lscher, Markus,Coetzee, Jacorien,Cole-Hamilton, David J.,Klankermayer, Jürgen,Leitner, Walter
-
supporting information
p. 13217 - 13225
(2015/03/30)
-
- Competing pathways in the photogeneration of didehydrotoluenes from (Trimethylsilylmethyl)aryl sulfonates and phosphates
-
The scope of the photochemical generation of a,n-didehydrotoluene diradicals from aryl sulfonates and phosphates and their chemistry are explored. The thermally inaccessible a,2- and a,4-intermediates are efficiently obtained by irradiation of ortho- and para-(trimethylsilylme-thyl)phenyl triflates through heterolytic splitting of the ester anion from the substrate in the triplet state. Triplet phenyl cations are formed and the loss of trimethylsilyl cation from them affords the desired diradicals (3Me3SiCH2C6H4-OZ→ 3Me3SiCH2C6H4+→CH2C6H4). Triplet sensitization is required, for which acetone is used throughout. Direct irradiation leads, on the contrary, to photo-Fries fragmentation (1Me3SiCH2C6H4O-Z→Me3SiCH2C6H4O· + Z). With mesylates, where ester cleavage is less convenient, a further competition from the triplet is direct desilylation. Didehydrotoluenes are also obtained from the corresponding phosphates, although with poor efficiency.
- Crespi, Stefano,Ravelli, Davide,Protti, Stefano,Albini, Angelo,Fagnoni, Maurizio
-
p. 17572 - 17578
(2015/02/18)
-
- Antimony(V) chloride as an efficient reagent for deprotection of methyl ethers
-
This paper proposes a new and efficient method for the deprotection of methyl ethers using antimony pentachloride at ambient temperature. The procedure described here is a facile and practical method for the removal of the methyl group from aryl and benzyl methyl ethers. High selectivity was observed for the removal of the methyl group from dimethoxyarenes. The notable advantages of this protocol are mild reaction conditions, high yields, and the facility of workup procedure. The mechanism of the ether cleavage is proposed to explain this new reaction. Georg Thieme Verlag Stuttgart New York.
- Saadati, Fariba,Meftah-Booshehri, Hamid
-
p. 1702 - 1706
(2013/09/02)
-
- A novel method for synthesis of benzyl alkyl ethers using Vanadium-based metal complex catalysts
-
A novel method has been developed for the synthesis of benzyl alkyl ethers in 25-85% yields via the reaction of toluene with alcohols in a CCl4 medium catalyzed by Et3N-activated VO(acac)2.
- Khusnutdinov,Bayguzina,Gallyamova,Dzhemilev
-
p. 261 - 266
(2012/10/29)
-
- Synthesis and reactivity of substituted alkoxymethylphosphonites and their derivatives
-
Alkoxy-substituted methylphosphonites and their derivatives are prepared using an organomagnesium method of synthesizing the organophosphorus compounds and alkoxymethylation of various PH acids and their derivatives. Also, certain properties of these promising compounds as important precursors of new functionalized organophosphorue compounds with alkoxymethyl fragments are presented.
- Prishchenko, Andrey A.,Livantsov, Mikhail V.,Novikova, Olga P.,Livantsova, Ludmila I.,Petrosyan, Valery S.
-
experimental part
p. 281 - 289
(2012/07/28)
-
- TiCl4-mediated direct N-alkylation of sulfonamides with inactive ethers
-
A TiCl4-mediated intermolecular or intramolecular direct N-alkylation reaction of sulfonamides with inactive ethers as alkylating agents was successfully achieved. This method provides a novel approach towards N-alkyl sulfonamides from inactive ethers via an easy workup procedure. Georg Thieme Verlag Stuttgart · New York.
- Chen, Jiayan,Dang, Ling,Li, Qiang,Ye, Yong,Fu, Shaomin,Zeng, Wei
-
supporting information; experimental part
p. 595 - 600
(2012/03/27)
-
- Impact of fluorine substituents on the rates of nucleophilic aliphatic substitution and β-elimination
-
A measure of the quantitative effect of proximate fluorine substituents on the rates of SN2 and E2 reactions has been obtained through a study mainly of reactions of fluorinated n-alkyl bromides with weak base, strong nucleophile azide ion and strong base/nucleophile methoxide ion in the protic solvent methanol and the aprotic solvent, DMSO. The order of reactivity for SN2 reactions of azide in methanol at 50 °C was found to be: n-alkyl-Br > n-alkyl-CHFBr > n-perfluoroalkyl-CH2CH 2Br n-perfluoroalkyl-CH2Br > n-alkyl-CF2Br. Approximate relative rates of reaction were: 1, 0.20, 0.12, 1 × 10 -4, -5. The order of reactivity for E2 reactions was found to be: n-perfluoroalkyl-CH2CH2Br n-alkyl-CF2Br > n-alkyl-CHFBr > n-alkyl-Br. The approximate relative rates for reaction of methoxide in methanol at 50 °C were: 1100, 4.4, 1.9, 1.
- Martinez, Henry,Rebeyrol, Adele,Nelms, Taylor B.,Dolbier Jr., William R.
-
experimental part
p. 167 - 175
(2012/03/27)
-
- Reductive etherification of aldehydes photocatalyzed by dicarbonyl pentamethylcyclopentadienyl iron complexes
-
The reductive etherification of aldehydes can be performed by the reaction with dialkylmethylsilanes in the presence of new iron(II) piano-stool catalysts of general formula Cp*Fe(CO)2Ar (Cp * = η5-C5Me5; Ar = Ph, 4-C6H4OCH3, 4-C6H4CH 3, Fc). This transformation is promoted by UV light and affords a simple route for the preparation of unsymmetrical alkyl ethers.
- Argouarch, Gilles,Grelaud, Guillaume,Roisnel, Thierry,Humphrey, Mark G.,Paul, Frédéric
-
supporting information
p. 5015 - 5018
(2012/11/07)
-
- Iron-catalyzed hydrosilylation of esters
-
The first hydrosilylation of esters catalyzed by a well defined iron complex has been developed. Esters are converted to the corresponding alcohols at 100 °C, under solvent-free conditions and visible light activation. Copyright
- Bezier, David,Venkanna, Gopaladasu T.,Castro, Luis C. Misal,Zheng, Jianxia,Roisnel, Thierry,Sortais, Jean-Baptiste,Darcel, Christophe
-
supporting information; experimental part
p. 1879 - 1884
(2012/09/22)
-
- α,n-didehydrotoluenes by photoactivation of (chlorobenzyl) trimethylsilanes: An alternative to enyne-allenes cyclization
-
Doubly radical: A novel entry to ?,n-didehydrotoluene (DHT) diradicals is disclosed and proceeds through the photochemical activation of (chlorobenzyl)trimethylsilanes with chloride loss and elimination of the SiMe3+ group (see scheme). The products formed in solution are indicative of the intermediacy of the three isomers of the ?,n-DHT
- Protti, Stefano,Ravelli, Davide,Mannucci, Barbara,Albini, Angelo,Fagnoni, Maurizio
-
supporting information; experimental part
p. 8577 - 8580
(2012/09/22)
-
- A new method for the Co-liquefaction of coal and waste tyre rubber into useful products using microwave metal interaction pyrolysis
-
A mixture of waste rubber of tyre and Makarwal coal of Pakistan was converted into oil using microwave metal interaction pyrolysis. The reactions were carried out in reactor containing copper coil which supported in high temperature microwave-assisted pyrolysis. The high temperature is generated by the interaction of microwaves with copper coil, coal and the bake clay reactor. Copper is used as antenna for the microwaves and it is believed that this antenna may also catalyze the pyrolysis process and affect the nature of products. This faster method of liquefaction gives 12% aqueous liquid, 58% oily liquid, 3% benzene soluble tar, 2 % gases and 25% residues. The liquid products were collected using cold traps and the amount of gas was obtained by taking difference. The mixture of tarry and oily liquid product was analyzed using GC/MS and found that it contains aliphatic and aromatic compounds. It was investigated by the chemical tests that the gases contain hydrogen sulfide and acetylene in addition to other fuel gases. The range of products and product formation is also discussed in this communication.
- Bashir, Nadia,Hussain, Khadim,Khan, Khalid Mohammed,Hussain, Zahid,Perveen, Shahnaz
-
experimental part
p. 162 - 167
(2012/05/07)
-
- New method for the synthesis of benzyl alkyl ethers mediated by FeSO 4
-
The synthesis of benzyl alkyl ethers from benzyl bromides and alcohols using FeSO4 as a recoverable and reusable mediator has been described without use of base and cosolvent under mild conditions.
- Joshi, Girdhar,Adimurthy, Subbarayappa
-
experimental part
p. 720 - 728
(2011/03/22)
-
- Indium(i)-catalyzed alkyl-allyl coupling between ethers and an allylborane
-
An efficient method for alkyl-allyl cross-coupling between ethers and a 9-BBN-derived allylborane catalyzed by indium(i) triflate has been developed. The allylborane proved to be essential to obtain the desired products in high yields. The reaction displayed good substrate scope including high functional group tolerance. The Royal Society of Chemistry 2011.
- Dao, Hai Thanh,Schneider, Uwe,Kobayashi, Shu
-
supporting information; experimental part
p. 692 - 694
(2011/03/22)
-
- Environmentally benign metal triflate-catalyzed reductive cleavage of the C-O bond of acetals to ethers
-
A protocol is described for the reductive cleavage of the C-O bond of aromatic and aliphatic acetals to ethers catalyzed by Cu(OTf)2 or Bi(OTf)3 at room temperature in excellent yields, without affecting aromatic rings, nitro, nitrile, ester and hydroxyl groups. This protocol represents an improvement in terms of atom economy compared to the previous methods, by distinctly decreasing the amount of the reducing reagent, 1,1,3,3-tetramethyldisiloxane (TMDS), and using a small amount of catalyst.
- Zhang, Yin-Jie,Dayoub, Wissam,Chen, Guo-Rong,Lemaire, Marc
-
experimental part
p. 2737 - 2742
(2011/11/29)
-
- Liquid ammonia as a dipolar aprotic solvent for aliphatic nucleophilic substitution reactions
-
The rate constants for the reactions of a variety of nucleophiles reacting with substituted benzyl chlorides in liquid ammonia (LNH3) have been determined. To fully interpret the associated linear free-energy relationships, the ionization constants of phenols ions in liquid ammonia were obtained using UV spectra. These equilibrium constants are the product of those for ion-pair formation and dissociation to the free ions, which can be separated by evaluating the effect of added ammonium ions. There is a linear relationship between the pKa of phenols in liquid ammonia and those in water of slope 1.68. Aminium ions exist in their unprotonated free base form in liquid ammonia and their ionization constants could not be determined by NMR. The rates of solvolysis of substituted benzyl chlorides in liquid ammonia at 25 °C show a Hammett ρ of zero, having little or no dependence upon ring substituents, which is in stark contrast with the hydrolysis rates of substituted benzyl halides in water, which vary 107 fold. The rate of substitution of benzyl chloride by substituted phenoxide ions is first order in the concentration of the nucleophile indicative of a SN2 process, and the dependence of the rate constants on the pKa of the phenol in liquid ammonia generates a Bronsted βnuc = 0.40. Contrary to the solvolysis reaction, the reaction of phenoxide ion with 4-substituted benzyl chlorides gives a Hammett ρ = 1.1, excluding the 4-methoxy derivative, which shows the normal positive deviation. The second order rate constants for the substitution of benzyl chlorides by neutral and anionic amines show a single Bronsted βnuc = 0.21 (based on the aqueous pKa of amine), but their dependence on the substituent in substituted benzyl chlorides varies with a Hammett ρ of 0 for neutral amines, similar to that seen for solvolysis, whereas that for amine anions is 0.93, similar to that seen for phenoxide ion.(Figure Presented)
- Ji, Pengju,Atherton, John,Page, Michael I.
-
scheme or table
p. 1425 - 1435
(2011/04/23)
-
- Expanded substrate scope and improved reactivity of ether-forming cross-coupling reactions of organotrifluoroborates and acetals
-
Mixed acetals and organotrifluoroborates undergo BF3· OEt2-promoted cross-couplings to give dialkyl ethers under simple, mild conditions. A survey of reaction partners identified a hydroxamate leaving group that improves the regioselectivity and product yield in the BF 3·OEt2-promoted coupling reaction of mixed acetals and potassium alkynyl-, alkenyl-, aryl- and heteroaryltrifluoroborates to access substituted dialkyl ethers. This leaving group enables the reaction to proceed rapidly under mild conditions (0 °C, 5-60 min) and permits reactions with electron-deficient potassium aryltrifluoroborates that are less reactive with other acetal substrates. A study of the reaction mechanism and characterization of key intermediates by NMR spectroscopy and X-ray crystallography identified a role for the hydroxamate moiety as a reversible leaving group that serves to stabilize the key oxocarbenium intermediate and the need for a slight excess of organodifluoroborane to serve as a catalyst. A secondary role for the boron nucleophile as an activating ligand was also considered. These studies provide the basis for a general class of reagents that lead to dialkyl ethers by a simple, predictable cross-coupling reaction.
- Vo, Cam-Van T.,Mitchell, T. Andrew,Bode, Jeffrey W.
-
supporting information; experimental part
p. 14082 - 14089
(2011/10/12)
-
- TiCl4-activated selective nucleophilic substitutions of tert-butyl alcohol and benzyl alcohols with π-donating substituents
-
TiCl4-activated selective nucleophilic substitution reactions of tert-butyl alcohol and benzyl alcohols with π-donating substituents in the presence of primary and secondary alcohols can be carried out with various oxygen, nitrogen and carbon nucleophiles in good yields.
- Tsai, Chen-Yu,Sung, Robert,Zhuang, Bo-Ren,Sung, Kuangsen
-
experimental part
p. 6869 - 6872
(2010/09/18)
-
- Ferric perchlorate as an efficient and useful catalyst for the selective benzylation and methylation of alcohols with benzyl chloride and methyl iodide
-
A mild and efficient method was developed for selective benzylation and methylation of hydroxyl compounds in the presence of a catalytic amount of ferric perchlorate. We showed that ferric perchlorate was very effective in selectively promoting the benzylation and methylation of primary aliphatic and benzylic alcohols versus secondary aliphatic alcohols and phenolic hydroxy groups. Graphical abstract: [Figure not available: see fulltext.]
- Behbahani, Farahnaz K.,Heravi, Majid M.,Oskooie, Hossien A.
-
experimental part
p. 181 - 184
(2010/03/26)
-
- [IrCl2Cp*(NHC)] complexes as highly versatile efficient catalysts for the cross-coupling of alcohols and amines
-
A comparative study on the catalytic activity of a series of [IrCl 2Cp*(NHC)] complexes in several C-O and C-N coupling processes implying hydrogen-borrowing mechanisms has been performed. The compound [IrCl2Cp*(InBu)] (Cp* = pentamethyl cyclopentadiene; InBu = 1,3-di-n-butylimidazolylidene) showed to be highly effective in the cross-coupling reactions of amines and alcohols, providing high yields in the production of unsymmetrical ethers and N-alkylated amines. A remarkable feature is that the processes were carried out in the absence of base, phosphine, or any other external additive. A comparative study with other known catalysts, such as Shvo's catalyst, is also reported.
- Prades, Amparo,Corberan, Rosa,Poyatos, Macarena,Peris, Eduardo
-
scheme or table
p. 11474 - 11479
(2009/12/03)
-
- A kinetic model for water reactivity (avoiding activities) for hydrolyses in aqueous mixtures - Selectivities for solvolyses of 4-substituted benzyl derivatives in alcohol-water mixtures
-
For solvolyses of various benzyl substrates in ethanol-water (EW) and methanol-water (MW) mixtures, product selectivities (S) are reported for chlorides at 75°C defined as follows using molar concentrations: S= ([ether product]/[alcohol product]) × ([water]/[alcohol solvent]). The results support earlier evidence that solvolyses of 4-nitrobenzyl substrates are S N2 processes, which are not susceptible to mechanistic changes over the whole range of solvents from water to alcohol. S values at 25 and/or 45°C in EW and MW, and additional kinetic data including kinetic solvent isotope effects (KSIE) are reported for solvolyses of 4-nitrobenzyl mesylate and tosylate. A kinetic model, explaining both rates and product, is proposed; a general medium effect due to solvent polarity is combined in one parameter with solvent effects on the nucleophilicity of the water and alcohol molecules acting as nucleophiles in SN2 reactions. According to this model, as alcohol is added to water the rate of reaction decreases due to a decrease in solvent polarity, but the nucleophilicity of water increases relative to alcohol. The availability of experimental rate and product data over the whole range of solvent compositions from alcohol to water, reveals limitations of alternative approaches using activities. Copyright
- Bentley, T. William,Koo, In Sun,Choi, Hojune,Llewellyn, Gareth
-
p. 251 - 256
(2008/09/20)
-
- Hydrogen bonding lowers intrinsic nucleophilicity of solvated nucleophiles
-
The relationship between nucleophilicity and the structure/environment of the nucleophile is of fundamental importance in organic chemistry. In this work, we have measured nucleophilicities of a series of substituted alkoxides in the gas phase. The functional group substitutions affect the nucleophiles through ion-dipole, ion-induced dipole interactions and through hydrogen bonding whenever structurally possible. This set of alkoxides serves as an ideal model system for studying nucleophiles under microsolvation settings. Marcus theory was applied to analyze the results. Using Marcus theory, we separate nucleophilicity into two independent components, an intrinsic nucleophilicity and a thermodynamic driving force determined solely by the overall reaction exothermicity. It is found that the apparent nucleophilicities of the substituted alkoxides are always much lower than those of the unsubstituted ones. However, ion-dipole, ion-induced dipole interactions, by themselves, do not significantly affect the intrinsic nucleophilicity; the decrease in the apparent nucleophilicity results from a weaker thermodynamic driving force. On the other hand, hydrogen bonding not only stabilizes the nucleophile but also increases the intrinsic barrier height by 3 to ~4 kcal mol-1. In this regard, the hydrogen bond is not acting as a perturbation in the sense of an external dipole but more directly affects the electronic structure and reactivity of the nucleophilic alkoxide. This finding offers a deeper insight into the solvation effect on nucleophilicity, such as the remarkably lower reactivities in nucleophilic substitution reactions in protic solvents than in aprotic solvents.
- Chen, Xin,Brauman, John I.
-
scheme or table
p. 15038 - 15046
(2009/03/12)
-
- A versatile procedure for synthesis of organic acids by cobalt carbonyl catalyzed carbonylation of organic halides
-
A versatile procedure for synthesis of a broad range of fatty-aromatic and aromatic acids by carbonylation of the corresponding halides under very mild conditions in the presence of cobalt carbonyl as a catalyst was suggested. The main principles of a flexible process for production of practically significant acids and their derivatives were developed.
- Zhesko,Boyarskii,Nikitina
-
p. 945 - 950
(2008/03/12)
-
- Iodine catalyzed selective O-alkylation of alcohols with orthoesters
-
In the present communication O-alkylation of a number of allylic and benzylic alcohols has been described.
- Kumar,Anjaneyulu,Joyasawal, Sipak,Pawan Chakravarthy,Naveen Kumar,Yadav
-
p. 189 - 192
(2008/02/13)
-
- Lewis acid-catalyzed reduction of dithioacetals by 1,4-cyclohexadiene
-
Dithioacetals were reduced by 1,4-cyclohexadiene in the presence of a catalytic amount of Lewis acid to afford the corresponding sulfides in good yields.
- Ikeshita, Kei-ichiro,Kihara, Nobuhiro,Sonoda, Motohiro,Ogawa, Akiya
-
p. 3025 - 3028
(2008/02/06)
-