- Bismuth subnitrate-catalyzed markovnikov-type alkyne hydrations under batch and continuous flow conditions
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Bismuth subnitrate is reported herein as a simple and efficient catalyst for the atom-economical synthesis of methyl ketones via Markovnikov-type alkyne hydration. Besides an effective batch process under reasonably mild conditions, a chemically intensified continuous flow protocol was also developed in a packed-bed system. The applicability of the methodologies was demonstrated through hydration of a diverse set of terminal acetylenes. By simply switching the reaction medium from methanol to methanol-d4, valuable trideuteromethyl ketones were also prepared. Due to the ready availability and nontoxicity of the heterogeneous catalyst, which eliminated the need for any special additives and/or harmful reagents, the presented processes display significant advances in terms of practicality and sustainability.
- ?tv?s, Sándor B.,Fül?p, Ferenc,Szécsényi, Zsanett
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- Method for preparing carbonyl compound through oxidative cleavage of visible light excitation aqueous solution quantum dot catalytic olefin compound
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The invention provides a method for preparing carbonyl compounds through oxidative cleavage of a visible light excitation aqueous solution quantum dot catalytic olefin compound. Belong to photocatalysis synthesis technical field. To the method, an aqueous solution quantum dot is used as a photocatalyst, and an aqueous solution quantum dot activated molecular oxygen catalytic oxidation aromatic alkene compound is excited by visible light to be cracked to prepare a carbonyl compound. Low-loading capacity is used, a simple aqueous solution quantum dot is used as a catalyst, the yield of the carbonyl compound is high, TON more than ten millions are obtained. The reaction conditions are mild, water serves as a main solvent for the reaction, and the carbonyl compound can be obtained by catalytic olefin compound oxidation cracking without addition of a cocatalyst or the like. The method is simple to operate, wide in substrate range and low in cost.
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Paragraph 0041
(2021/11/10)
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- Visible-Light-Driven Oxidative Cleavage of Alkenes Using Water-Soluble CdSe Quantum Dots
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The oxidative cleavage of C=C bonds is an important chemical reaction, which is a popular reaction in the photocatalytic field. However, high catalyst-loading and low turnover number (TON) are general shortcomings in reported visible-light-driven reactions. Herein, the direct oxidative cleavage of C=C bonds through water-soluble CdSe quantum dots (QDs) is described under visible-light irradiation at room temperature with high TON (up to 3.7×104). Under the same conditions, water-soluble CdSe QDs could also oxidize sulfides to sulfoxides with 51–84 % yields and TONs up to 3.4×104. The key features of this photocatalytic protocol include high TONs, wide substrates scope, low catalyst loadings, simple and mild reaction conditions, and molecular O2 as the oxidant.
- Li, Jianing,Zhao, Jingnan,Ma, Cunfei,Yu, Zongyi,Zhu, Hongfei,Yun, Lei,Meng, Qingwei
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p. 4985 - 4992
(2021/10/16)
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- Enantiocomplementary C–H Bond Hydroxylation Combining Photo-Catalysis and Whole-Cell Biocatalysis in a One-Pot Cascade Process
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Enantiocomplementary hydroxylation of alkyl aromatics through a one-pot photo-biocatalytic cascade reaction is described. The photoredox process is implemented in aqueous phase with O2 as oxidant and the subsequent (R)- or (S)-selective bioreduction is performed by whole cell system without the addition of the expensive cofactor (NADPH). This mild, operationally simple protocol transforms a wide variety of readily available aromatic compounds into valuable chiral alcohols with high yield (up to 90 %) and stereoselectivity (up to 99 %), thereby displaying important potentials in organic synthesis.
- Peng, Yongzhen,Li, Danyang,Fan, Jiajie,Xu, Weihua,Xu, Jian,Yu, Huilei,Lin, Xianfu,Wu, Qi
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p. 821 - 825
(2020/02/20)
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- Redox-driven deracemization of secondary alcohols by sequential ether/O2-mediated oxidation and Ru-catalyzed asymmetric reduction
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The deracemization of benzylic alcohols has been achieved using a redox-driven one-pot two-step process. The racemic alcohols were oxidized by bis(methoxypropyl) ether and oxygen to give the ketone intermediates, followed by an asymmetric transfer hydrogenation with a chiral ruthenium catalyst. This compatible oxidation/reduction process gave the enantiomerically enriched alcohols with up to 95% ee values.
- Yang, Bing,Cui, Peng,Chen, Yongsheng,Liu, Qixing,Zhou, Haifeng
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supporting information
(2020/10/14)
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- The synthesis of methyl triazole-4-carboxylate gold(I) complex and application on allene synthesis and alkyne hydration
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The methyl 1H-1,2,3-triazole-4-carboxylate containing a strong electron-withdrawing group was developed and applied as a ligand for gold(I) cations. The resulting ester-triazole gold(I) complex was investigated for its efficiency in catalyzing allene synthesis and alkyne hydration, in which an excellent catalytic efficiency was observed with low catalyst loadings.
- Hu, Wenkang,Shan, Liang,Ma, Fudong,Zhang, Yilin,Yang, Yongchun,Wang, Dawei
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- Balancing Bulkiness in Gold(I) Phosphino-triazole Catalysis
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The syntheses of a series of 1-phenyl-5-phosphino 1,2,3-triazoles are disclosed, within which, the phosphorus atom (at the 5-position of a triazole) is appended by one, two or three triazole motifs, and the valency of the phosphorus(III) atom is completed by two, one or zero ancillary (phenyl or cyclohexyl) groups respectively. This series of phosphines was compared with tricyclohexylphosphine and triphenylphosphine to study the effect of increasing the number of triazoles appended to the central phosphorus atom from zero to three triazoles. Gold(I) chloride complexes of the synthesised ligands were prepared and analysed by techniques including single-crystal X-ray diffraction structure determination. Gold(I) complexes were also prepared from 1-(2,6-dimethoxy)-phenyl-5-dicyclohexyl-phosphino 1,2,3-triazole and 1-(2,6-dimethoxy)-phenyl-5-diphenyl-phosphino 1,2,3-triazole ligands. The crystal structures thus obtained were examined using the SambVca (2.0) web tool and percentage buried volumes determined. The effectiveness of these gold(I) chloride complexes to serve as precatalysts for alkyne hydration were assessed. Furthermore, the regioselectivity of hydration of but-1-yne-1,4-diyldibenzene was probed.
- Zhao, Yiming,Wakeling, Matthew G.,Meloni, Fernanda,Sum, Tze Jing,van Nguyen, Huy,Buckley, Benjamin R.,Davies, Paul W.,Fossey, John S.
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p. 5540 - 5548
(2019/08/07)
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- Iron(III)-Catalyzed Hydration of Unactivated Internal Alkynes in Weak Acidic Medium, under Lewis Acid-Assisted Br?nsted Acid Catalysis
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Alkylarylalkynes are converted with full regioselectivity into the corresponding arylketones by formal hydration of the triple bond under weak acidic conditions, at times and temperatures (≤95 °C) comparable to those used for terminal alkynes. The process catalyzed by Fe2(SO4)3nH2O in glacial acetic acid exhibits good functional group compatibility, including that with bulky triple bond substituents, and can be extended to the one-pot transformation of aryltrimethylsilylacetylenes into acetyl derivatives via a desilylation-hydration sequence. The overall reactivity pattern along with proton affinity data indicate that the triple bond is activated by proton transfer rather than by π-interaction with the metal ion. This mechanistic feature, at variance with that of noble metal catalysts, accounts for the total regioselectivity and the insensitivity to steric hindrance exhibited by the Fe2(SO4)3nH2O/AcOH catalytic system. (Figure presented.).
- Antenucci, Achille,Flamini, Piergiorgio,Fornaiolo, Marco Valerio,Di Silvio, Sergio,Mazzetti, Sara,Mencarelli, Paolo,Salvio, Riccardo,Bassetti, Mauro
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p. 4517 - 4526
(2019/08/26)
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- Electrochemical benzylic oxidation of C-H bonds
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Oxidized products have become increasingly valuable as building blocks for a wide variety of different processes and fine chemistry, especially in the benzylic position. We report herein a sustainable protocol for this transformation through C-H functionalization and is performed using electrochemistry as the main power source and tert-butyl hydroperoxide as the radical source for the C-H abstraction. The temperature conditions reported here do not increase above 50 °C and use an aqueous-based medium. A broad substrate scope is explored, along with bioactive molecules, to give comparable and increased product yields when compared to prior reported literature without the use of electrochemistry.
- Marko, Jason A.,Durgham, Anthony,Bretz, Stacey Lowery,Liu, Wei
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supporting information
p. 937 - 940
(2019/01/23)
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- Hydration of aromatic terminal alkynes catalyzed by sulfonated condensed polynuclear aromatic (S-COPNA) resin in water
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Hydration of aromatic terminal alkynes in the presence of a catalytic amount of sulfonated condensed polynuclear aromatic (S-COPNA) resin in water gave the corresponding methyl ketones in good yields. On the other hand, aliphatic terminal alkynes did not react at all under the employed conditions. Chemoselective hydration of aromatic terminal alkyne in the presence of aliphatic terminal alkyne catalyzed by S-COPNA resin was carried out.
- Tanemura, Kiyoshi,Suzuki, Tsuneo
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supporting information
p. 955 - 958
(2017/02/18)
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- Palladium catalyzed decarboxylative acylation of arylboronic acid with ethyl cyanoacetate as a new acylating agent: Synthesis of alkyl aryl ketones
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Palladium catalyzed acylation of arylboronic acid containing various functional groups was performed efficiently by ethyl cyanoacetate/substituted ethyl cyanoacetate as the acylating agent in aqueous triflic acid medium. The alkyl aryl ketones were obtained in good to excellent yields, first by addition of arylboronic acid to the nitrile group of ethyl cyanoacetate and their derivatives, followed by in situ decarboxylation of the resulting β-ketoester.
- Yousuf, Md,Das, Tuluma,Adhikari, Susanta
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p. 8763 - 8770
(2015/11/10)
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- Synthesis of industrially important aromatic and heterocyclic ketones using hierarchical ZSM-5 and Beta zeolites
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Hierarchical ZSM-5 and Beta zeolites were investigated in the synthesis of wide range of industrially important aromatic/heterocyclic ketones by Friedel-Crafts acylation and benzoylation reactions. For comparative study, conventional ZSM-5 and Beta, and amorphous mesoporous Al-MCM-41 were investigated. Hierarchical zeolites were prepared by multi-ammonium structure directing agents whereas conventional zeolites were prepared by mono-ammonium structure directing agents. Among the catalysts investigated in this study, hierarchical Beta exhibited the highest reactant conversion in the acylation and benzoylation reactions. In this study, the systematic assessment of the catalytic activity of acid catalysts for wide range of aromatic and heterocyclic compounds is shown under one umbrella. To the best of our knowledge, these reactions over hierarchical zeolites (ZSM-5 and Beta) are reported here for the first time. Structure activity relationship is explained based on the physico-chemical properties, molecular size, reactivity of reactants, and reaction mechanism. Catalysts can be easily recovered and reused with negligible loss in the catalytic activity.
- Kore, Rajkumar,Srivastava, Rajendra,Satpati, Biswarup
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p. 129 - 141
(2015/09/28)
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- Metal free visible light driven oxidation of alcohols to carbonyl derivatives using 3,6-di(pyridin-2-yl)-1,2,4,5-tetrazine (pytz) as catalyst
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3,6-Di(pyridin-2-yl)-1,2,4,5-tetrazine (pytz) catalyzed oxidation of alcohols to the corresponding carbonyl compounds under visible light irradiation is described. This reaction occurs smoothly at room temperature and shows good tolerance of functional groups. It provides an alternative approach for the synthesis of alkyl and aryl aldehydes and ketones.
- Samanta, Suvendu,Biswas, Papu
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p. 84328 - 84333
(2015/10/28)
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- Bulky, spherical, and fluorinated anion BArF induces 'on-water' activity of silver salt for the hydration of terminal alkynes
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AgBArF displays remarkable 'on-water' activity for catalytic hydration of terminal alkynes although it is ineffective in common organic solvents. Liquid alkynes do not require additive or co-solvent whereas a small amount of ethyl acetate triggers quantitative conversions for solid alkynes.
- Saha, Sayantani,Sarbajna, Abir,Bera, Jitendra K.
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supporting information
p. 1444 - 1447
(2014/03/21)
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- Acid-catalyzed hydration of alkynes in aqueous microemulsions
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Terminal aromatic alkynes are converted rapidly into ketones in a regioselective manner by treatment of their microemulsions with 0.33 M mineral acid between 80 and 140 °C. Internal and aliphatic acetylenes are likewise hydrated, but require longer reaction periods. The products are easily isolated from the reaction mixtures by phase separation. Replacement of H2O by D2O leads to the formation of trideuteriomethyl ketones. Copyright
- Nairoukh, Zackaria,Avnir, David,Blum, Jochanan
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p. 430 - 432
(2013/04/24)
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- AgOTf catalyzed hydration of terminal alkynes
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The silver catalysis towards the hydration of terminal alkynes is explored using Silver(I) triflate (AgOTf). The reaction leads to the formation of only Markovnikov addition product with excellent yield. Copyright
- Das, Rima,Chakraborty, Debashis
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p. 722 - 726
(2013/02/22)
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- Microwave-assisted one-step synthesis of acetophenones via palladium-catalyzed regioselective arylation of vinyloxytrimethylsilane
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The regiochemistry of the palladium-mediated arylation (Heck arylation) of enol ethers is sensitive to the structure of the enol ether, the arylating agent and the catalytic system. In this study, an effective and practical method was successfully developed for the synthesis of acetophenones with high regioselectivity under palladium-catalyzed conditions. A variety of acetophenones was readily prepared from aryl iodides in good to excellent yields under microwave irradiation in a single step. The key feature of our new protocol is the use of vinyloxytrimethylsilane as a highly regioselective acylation reagent. Copyright
- Qian, Wangke,Zhang, Lei,Sun, Haifeng,Jiang, Hualiang,Liu, Hong
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supporting information
p. 3231 - 3236
(2013/01/15)
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- Aroma compounds generated from thermal reaction of l-ascorbic acid with l-cysteine
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The reaction of l-ascorbic acid with l-cysteine in heated aqueous solution (141 ± 1 °C) at five different pH values (5.00, 6.00, 7.00, 8.00, or 9.00) for 2 h, resulted in the formation of a complex mixture of aroma volatiles. The volatile compounds generated were analysed by SPME-GC-MS. The results gave 43 aroma compounds. The reaction between l-ascorbic acid and l-cysteine led mainly to the formation of alicyclic sulphur compounds, thiophenes, thienothiophenes, thiophenones, thiazoles and pyrazines, most of which contain sulphur. Many of these volatiles had meaty flavour. The origin of many of the compounds was explained. The studies showed that thienothiophenes and thienones were formed mainly at acidic pH. In contrast, higher pH values could promote the production of thiophenes, thiazoles and pyrazines.
- Yu, Ai-Nong,Zhang, Ai-Dong
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experimental part
p. 1060 - 1065
(2011/12/02)
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- SULFONAMIDE INHIBITORS OF CARBONIC ANHYDRASE
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The present invention relates to new sulfonamide inhibitors of carbonic anhydrase activity, pharmaceutical compositions thereof, and methods of use thereof.
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Page/Page column 14
(2010/12/29)
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- The first heterogeneous carbonylative Stille coupling of organostannanes with aryl iodides catalyzed by MCM-41-supported bidentate phosphine palladium(0) complex
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The first heterogeneous carbonylative Stille coupling reaction of organostannanes with aryl iodides under an atmospheric pressure of carbon monoxide has been achieved in DMF at 80 °C in the presence of a catalytic amount of an MCM-41-supported bidentate phosphine palladium(0) complex [MCM-41-2P-Pd(0)], yielding a variety of unsymmetrical ketones in good to high yields. This polymeric palladium catalyst exhibited higher activity and selectivity than PdCl2(PPh3)2 and can be recovered and recycled by a simple filtration of the reaction solution and used for at least 10 consecutive trials without any decrease in activity. Our system not only avoids the use of carbon monoxide under pressure, but also solves the basic problem of palladium catalyst recovery and reuse. The Royal Society of Chemistry 2009.
- Cai, Mingzhong,Zheng, Guomin,Ding, Guodong
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experimental part
p. 1687 - 1693
(2010/06/11)
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- Palladium-catalyzed regiocontrolled internal heteroarylation of electron-rich olefins with heteroaryl halides
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A highly efficient palladium-catalyzed Heck coupling reaction of heteroaryl halides with electron-rich vinyl ether and hydroxyalkyl vinyl ethers is described. It was found that the choice of solvent, ligand, and reaction temperature had a fundamental influence on the regioselectivity and reactivity of the reaction, and the combination of Pd(OAc)2 and DPPF in ethylene glycol led to the most effective catalytic system. Under these conditions, a variety of heteroaryl halides reacted very quickly with electron-rich olefins to afford exclusively the branched products in good to excellent yields without employing triflates, halide scavengers, or ionic liquids.
- Xu, Dan,Liu, Zhihua,Tang, Weijun,Xu, Lijin,Hyder, Zeynab,Xiao, Jianliang
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body text
p. 6104 - 6107
(2009/04/04)
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- Synthesis of α-heteroarylpropanoic acid via asymmetric hydroformylation catalyzed by Rh(I)-(R,S)-BINAPHOS and the subsequent oxidation
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(Chemical Equation Presented) The asymmetric hydroformylation of vinyl heteroarenes (vinylfurans and vinylthiophenes) was investigated by using Rh(I)-BINAPHOS derivatives as a catalyst. The hydroformylation of vinylthiophenes 1 gave the corresponding branched aldehydes 2 with high enantiopurities as major products. Oxidation of the aldehydes 2 successfully afforded α-heteroarylpropanoic acids 4 in good yields. In addition, the aldehydes 2 were reduced to alcohols 5 without loss of enantiomeric excess.
- Tanaka, Ryo,Nakano, Koji,Nozaki, Kyoko
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p. 8671 - 8676
(2008/03/12)
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- Highly regioselective internal heck arylation of hydroxyalkyl vinyl ethers by aryl halides in water
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(Chemical Equation Presented) Highly regioselective and fast Pd(0)-catalyzed internal α-arylation of ethylene glycol vinyl ether with aryl halides was shown to be possible in water without the need for any halide scavengers or ionic liquid additives. This presents, to our knowledge, the first case of water being utilized in the selective arylation of electron-rich olefins. Resulting α-products were hydrolyzed and isolated as corresponding acetophenones in good to excellent yields when using aryl bromides and with good to moderate yields in the case of aryl iodides. Microwave irradiation was shown to be beneficial in activation of aryl chlorides toward the internal Heck arylation. The scope of the protocol was further increased to include different hydroxyalkyl vinyl ethers, these all giving selectively only branched α-products. Finally, the active role of the hydroxy group in directing the regioselectivity toward internal arylation of electron-rich olefins, even in nonpolar toluene, was revealed.
- Arvela, Riina K.,Pasquini, Serena,Larhed, Mats
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p. 6390 - 6396
(2008/02/10)
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- PROCESS FOR PRODUCING 3-SUBSTITUTED THIOPHENE
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A process for producing a 3-substituted thiophene represented by the general formula (2): (wherein R represents cyano, formyl, carboxy, optionally substituted hydrocarbyloxycarbonyl, or optionally substituted acyl), characterized by reacting a vinyl compound represented by the general formula (1): RCH=CHY (wherein R has the same meaning as defined above; and Y is a leaving group) with α-mercaptoacetaldehyde or a polymer thereof.
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Page/Page column 14-15
(2008/06/13)
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- Efficient and selective Al-catalyzed alcohol oxidation via oppenauer chemistry
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A highly active and selective Al-based catalytic Oppenauer (O) oxidation is reported. Quantitative and selective oxidations of a variety of benzylic, propargylic, allylic, and aliphatic primary and secondary alcohols were achieved using nitrobenzaldehyde derivatives as the oxidant and simple aluminum compounds as precatalysts. Copyright
- Graves, Christopher R.,Zeng, Bi-Shun,Nguyen, SonBinh T.
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p. 12596 - 12597
(2008/02/03)
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- Highly regioselective Heck reactions of heteroaryl halides with electron-rich olefins in ionic liquid
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Palladium-catalyzed Heck reactions of the heteroaryl halides, halopyridines, bromoquinoline and bromothiophenes, with the electron-rich olefins vinyl ethers and allyl alcohol were shown to give essentially only the branched olefins in an imidazolium ionic liquid, whereas in molecular solvents a mixture of regioisomers was formed. The method obviates the need for aryl triflates and stoichiometric inorganic salt additives, providing an easy entry to functionalized heteroaromatics incorporating acetyl and 2-allyl alcohol functionalities.
- Pei, Wen,Mo, Jun,Xiao, Jianliang
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p. 3546 - 3551
(2007/10/03)
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- COMPOSITIONS USEFUL AS INHIBITORS OF ROCK AND OTHER PROTEIN KINASES
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The present invention relates to substitute thiazole and thiophene derivatives useful as inhibitors of rock and other protein kinaeses. The invention also provides pharmaceutically acceptable compositions comprising said compounds and methods of using the compositions in the treatment of various disease, conditions, or disorders, including proliferative, cardiac and neurodegenerative diseases.
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Page 107-108
(2010/02/07)
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- Aqueous DMF - Potassium carbonate as a substitute for thallium and silver additives in the palladium-catalyzed conversion of aryl bromides to acetyl arenes
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Highly selective palladium-catalyzed internal α-arylations of alkyl vinyl ethers with aryl and heteroaryl bromides were conveniently conducted in aqueous DMF with potassium carbonate as base and with DPPP as bidentate ligand. The corresponding acetyl arene products were, after hydrolysis, isolated in good to excellent yields. This Heck reaction procedure does not require toxic thallium or expensive silver salt additives, is promoted by water, and is suggested to proceed via charged organopalladium intermediates. Single-mode microwave irradiation was utilized in one example to shorten the reaction time.
- Vallin,Larhed,Hallberg
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p. 4340 - 4343
(2007/10/03)
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- Additions of Alkyllanthanum Triflates to Carbonyl Compounds: Reactive Organometallic Nucleophiles
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Addition of alkyl- or aryllithium compounds to lanthanum(III) triflate in ethereal solvents produces the title reagents 2 that undergo nucleophilic addition to carbonyl compounds under mild conditions.These reagents resemble alkylcerium halides in their reactions with enolizable carbonyl compounds but are more reactive.In particular, they are useful for the conversion of hindered, tertiary amides to the ketones. 1H NMR spectroscopy was employed to clarify mechanistic aspects of this addition process.The title reagents actually appear to be a mixture of several species; formulation of their structure has proven elusive.However, in the presence of a tertiary amide, these species react to give a single, tetrahedral intermediate, which is quite stable in solution.
- Collins, Scott,Hong, Yaping,Hoover, Gordon J.,Veit, Jennifer R.
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p. 3565 - 3568
(2007/10/02)
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- CATALYTIC REDUCTIVE DEHALOGENATION OF THIOPHENE DERIVATIVES
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A method for the preparation of 3-substituted derivatives of thiophene by reductive dehalogenation of 2,5-dihalo-substituted thiophenes in the presence of a palladium complex is proposed.The dehalogenation reaction is a stepwise process.The presence of an acyl group in the 3 position increases the rate of the process.
- Sharf, V. Z.,Taits, S. Z.,Gurovets, A. S.,Vol'kenshtein, Yu. B.,Fabrichnyi, B. P.,Shcherbakova, S. I.
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p. 130 - 133
(2007/10/02)
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