- Tuning Regioselectivity of Wacker Oxidation in One Catalytic System: Small Change Makes Big Step
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A regioselectivity switchable aerobic Wacker-Tsuji oxidation has been developed using catalytic tert-butyl nitrite as a simple organic redox cocatalyst. By solely switching the solvent, either substituted aldehydes or ketones could be prepared under mild
- Hu, Kang-Fei,Ning, Xiao-Shan,Qu, Jian-Ping,Kang, Yan-Biao
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p. 11327 - 11332
(2018/09/06)
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- Tert-Butyl Nitrite: Organic Redox Cocatalyst for Aerobic Aldehyde-Selective Wacker-Tsuji Oxidation
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An aldehyde-selective aerobic Wacker-Tsuji oxidation is developed. Using tert-butyl nitrite as a simple organic redox cocatalyst instead of copper or silver salts, a variety of aldehydes were achieved as major products in up to 30/1 regioselectivity as well as good to high yields at room temperature.
- Ning, Xiao-Shan,Wang, Mei-Mei,Yao, Chuan-Zhi,Chen, Xian-Min,Kang, Yan-Biao
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p. 2700 - 2703
(2016/06/15)
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- Hypervalent Iodine as a Terminal Oxidant in Wacker-Type Oxidation of Terminal Olefins to Methyl Ketones
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A mimic of the Wacker process for C=O bond formation in terminal olefins can be initiated by a combination of the Pd(II) and hypervalent iodine reagent, Dess-Martin periodinane to generate methyl ketones. This operationally simple and scalable method offers Markovnikov selectivity, has good functional group compatibility, and is mild and high yielding.
- Chaudhari, Dipali A.,Fernandes, Rodney A.
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p. 2113 - 2121
(2016/03/15)
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- Selective access to all four diastereomers of a 1,3-amino alcohol by combination of a keto reductase- and an amine transaminase-catalysed reaction
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The biocatalytic synthesis of chiral amines has become a valuable addition to the chemists' toolbox. However, the efficient asymmetric synthesis of functionalised amines bearing more than one stereocentre, such as 1,3-amino alcohols, remains challenging. By employing a keto reductase (KRED) and two enantiocomplementary amine transaminases (ATA), we developed a biocatalytic route towards all four diastereomers of 4-amino-1-phenylpentane-2-ol as a representative molecule bearing the 1,3-amino alcohol functionality. Starting from a racemic hydroxy ketone, a kinetic resolution using an (S)-selective KRED provided optically active hydroxy ketone (86% ee) and the corresponding diketone. Further transamination of the hydroxy ketone was performed by either an (R)- or an (S)-selective ATA, yielding the (2R,4R)- and (2R,4S)-1,3-amino alcohol diastereomers. The remaining two diastereomers were accessible in two subsequent asymmetric steps: the diketone was reduced regio- and enantioselectively by the same KRED, which yielded the (S)-configured hydroxy ketone. Eventually, the subsequent transamination of the crude product with (R)- and (S)-selective ATAs yielded the remaining (2S,4R)- and (2S,4S)-diastereomers, respectively.
- Kohls, Hannes,Anderson, Mattias,Dickerhoff, Jonathan,Weisz, Klaus,C?rdova, Armando,Berglund, Per,Brundiek, Henrike,Bornscheuer, Uwe T.,H?hne, Matthias
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supporting information
p. 1808 - 1814
(2015/06/02)
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- Iron(III) sulfate as terminal oxidant in the synthesis of methyl ketones via wacker oxidation
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An efficient and environmentally benign method using Fe(III) sulfate as a terminal oxidant in the synthesis of methyl ketones from terminal olefins via the Wacker process is developed. The methodology offers high selectivity for a Markonikov product, shows good functional group compatibility, involves mild reaction conditions, and is operationally simple. Fe2(SO 4)3 is the sole terminal oxidant in this process. The method holds potential for future applications in organic synthesis.
- Fernandes, Rodney A.,Chaudhari, Dipali A.
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p. 5787 - 5793
(2014/07/08)
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- Synthesis of methyl ketones from terminal olefins using PdCl 2/CrO3 system mimicking the Wacker process
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An efficient synthesis of methyl ketones from terminal olefins using PdCl2/CrO3 system mimicking the Wacker process is developed. The method shows good functional groups compatibility, no aldehyde by-products and is operationally simple. CrO3 is the sole oxidant and replaces both Cu-salts and molecular oxygen, traditionally used in this process. The method holds potential for future applications in organic synthesis.
- Fernandes, Rodney A.,Bethi, Venkati
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p. 4760 - 4767
(2014/06/24)
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- Palladium(II)-catalyzed dicarboxymethylation of chiral allylic alcohols: Chirality transfer affording optically active diesters containing three contiguous chiral centers
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This manuscript describes the extension of Stille's palladium-catalyzed olefin dicarbonylation reaction to chiral allylic alcohols with chirality transfer to afford the corresponding chiral alcohol functionalized with bis-carbomethoxy esters, containing three contiguous chiral centers, in good to excellent diastereoselectivities (78-98%).
- Hamed, Othman,Henry, Patrick M.,Becker, Daniel P.
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supporting information; experimental part
p. 3514 - 3517
(2010/09/05)
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- Aldol reaction of enol esters catalyzed by cationic species paired with tetrakis(pentafluorophenyl)borate
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The crossed aldol reaction of enol esters, which are weak carbon nucleophiles, with aldehydes was effectively carried out under mild conditions by using a catalytic amount of several cationic species paired with tetrakis(pentafluorophenyl)borate.
- Yanagisawa,Shimamura,Iida,Matsuo,Mukaiyama
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p. 1838 - 1840
(2007/10/03)
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- Anodic oxidation of α-alkoxycarbonyloxy and α-acyloxy organotin compounds
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Electrochemical behavior of α-alkoxycarbonyloxy and α-acyloxy organotin compounds was studied. Preparative anodic oxidation in the presence of allylsilanes or silyl enol ethers gave the corresponding coupling products.
- Yoshida, Jun-Ichi,Morita, Yuko,Ishichi, Yuji,Isoe, Sachihiko
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p. 5247 - 5250
(2007/10/02)
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- ACYLATION OF ALKENES WITH ACETYL FLUOROBORATE IN THE PRESENCE OF ACETIC ACID ANHYDRIDE
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The acylation of styrene, vinylcyclopropane, methylenecyclobutane, and isobutylene with acetyl fluoroborate in the presence of acetic anhydride takes place as the conjugate addition of the acetyl and acetoxy groups and leads to preparative yields of the corresponding acetoxy ketones.
- Shastin, A. V.,Balenkova, E. S.
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p. 870 - 872
(2007/10/02)
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- REGIOSELECTIVE OXIDATION OF INTERNAL OLEFINS BEARING NEIGHBORING OXYGEN FUNCTIONS BY MEANS OF PALLADIUM CATALYSTS. PREPARATION OF β-ALKOXY OR ACETOXY KETONES FROM ALLYL AND HOMOALLYL ETHERS OR ESTERS
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A new preparative method of β- and γ-alkoxy (acetoxy) ketones, which are important precursors of vinyl ketones and 1,4-diketones, respectively, is presented.With PdCl2/CuCl/O2 or PdCl2/p-benzoquinone catalyst system, internal olefins bearing allylic alkoxy or acetoxy group underwent regioselective oxidation to form the corresponding β-alkoxy or β-acetoxy ketones.Similarly, γ-acetoxy ketones were obtained from homoallyl acetates having internal olefins with high regioselectivity.
- Tsuji, Jiro,Nagashima, Hideo,Hori, Kimihiko
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p. 2679 - 2682
(2007/10/02)
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