straightforward process for the preparation of optically active protected cyanohydrins, important building blocks for the synthesis of drugs and agrochemicals, has been established. Lipase B from Candida Antarctica (CAL-B) catalysed the kinetic resolution of racemic cyanohydrin acetates under mild conditions. The resulting labile cyanohydrins were reprotected either by an enzyme-catalysed route involving the
Palladium-Catalyzed Cross-Coupling of Cyanohydrins with Aryl Bromides: Construction of Biaryl Ketones
作者:Huifang Dai、P. Andrew Evans、Jadab Majhi、Bohang Zhou、Yuxin Zhuang、Mai-Jan Tom
DOI:10.1055/a-1850-3687
日期:——
The palladium-catalyzedcross-coupling of the lithium anion of aryl tert-butyldimethylsilyl-protected cyanohydrins with arylbromides followed by in situ deprotection with fluoride ion provides a convenient and versatile approach to biaryl ketones. This protocol represents the first example of a palladium-catalyzed arylation of a cyanohydrin, which functions as an acyl anion equivalent. Hence, in contrast
Preparation of β-hydroxyketones (aldols) from the alkylation of O-silyl aryl cyanohydrins with epoxides
作者:Lissa D. Gilreath、Diamond R. Melendez、Caylie A. McGlade、Jennifer E. Shoemaker、Dakoda W. Mullinax、Aaron M. Hartel
DOI:10.1016/j.tetlet.2022.154334
日期:2023.2
β-Hydroxyketones (aldols) are prepared from the alkylation-deprotection of O-silylated aryl cyanohydrins with epoxides. Key to the success of the method was the suppression of an in situ cyclic imidate formation that occurs upon initial opening of the epoxide ring.
P(RNCH2CH2)N: efficient catalysts for the cyanosilylation of aldehydes and ketones
作者:Brandon M. Fetterly、John G. Verkade
DOI:10.1016/j.tetlet.2005.09.032
日期:2005.11
The 1,2-addition of trialkylsilylcyanides to aldehydes and ketones produces the corresponding protected cyanohydrins in good to excellent yields when carried out at 0 degrees C to room temperature in the presence of catalytic amounts of the nonionic strong base P(RNCH2CH2)N (R = Me, i-Pr) in THF. These catalysts are easily removed from the product by hydrolysis or column filtration through silica gel. (c) 2005 Published by Elsevier Ltd.
One-Step Synthesis of Substituted α-Pyrones from Cyclobutenediones and Lithiated <i>O</i>-Silyl Cyanohydrins