Enantioselective Synthesis of Aliphatic Cyanohydrin Acetates
作者:Ulf Hanefeld、Lars Veum
DOI:10.1055/s-2005-872671
日期:——
When the standard conditions for the enantioselective synthesis of cyanohydrin acetates via dynamic kinetic resolution are applied to aliphatic substrates, only a kinetic resolution is observed. However, by exchanging the base (Amberlite) against NaCN, quantitative conversions and good enantioselectivities are obtained.
A new (R)-hydroxynitrile lyase from Prunus mume: asymmetric synthesis of cyanohydrins
作者:Samik Nanda、Yasuo Kato、Yasuhisa Asano
DOI:10.1016/j.tet.2005.08.105
日期:2005.11
A new hydroxynitrile lyase (HNL) was isolated from the seed of Japanese apricot (Prunus mume). The enzyme has similar properties with HNL isolated from other Prunus species and is FAD containing enzyme. It accepts a large number of unnatural substrates (benzaldehyde and its variant) for the addition of HCN to produce the corresponding cyanohydrins in excellent optical and chemical yields. A new HPLC
The directamination of cyanohydrins with amines via a catalytic cyano-borrowing reaction was developed. The transformation features broad substrate scope, excellent functional group compatibility, and very mild and simple operations. Moreover, a titanium catalyst supported by quinine and (S)-BINOL ligands enabled an asymmetric cyano-borrowing reaction with moderate to high enantioselectivity.
An Efficient and Solvent-Free
Synthesis of Mixed Ortho Esters
作者:Ross McGeary、Kelly Cosgrove
DOI:10.1055/s-2008-1078215
日期:——
Primary, secondary and electron-deficient tertiary alcohols react rapidly with ketene dimethyl acetal to form mixed ortho esters, without catalysts and under solvent-free conditions. 1,2-Diols yield bis(mixed ortho esters), rather than cyclic ortho esters.
Dibutyltin Dimethoxide-Catalyzed Cyano Transfer to Aldehydes and Imines
作者:Akira Yanagisawa、Takuya Matsumoto、Naoyuki Kushihara、Kazuhiro Yoshida
DOI:10.1002/adsc.201000409
日期:2010.11.22
A novel reaction involving cyano transfer from benzophenone cyanohydrin to aldehydes and imines was realized by usingdibutyltindimethoxide as a catalyst. Various cyanohydrins and α-amino nitriles were obtained in moderate to high yields by this reaction. Ketimines also showed remarkable reactivity as cyano acceptors under conventional reaction conditions. This catalytic reaction was further applied