Enantioselective and diastereoselective syntheses of cyanohydrin carbonates
作者:Yuri N. Belokon'、William Clegg、Ross W. Harrington、Eisuke Ishibashi、Hiroshi Nomura、Michael North
DOI:10.1016/j.tet.2007.07.016
日期:2007.9
cocatalyst are developed. Under these conditions, two chiral cyanoformates also reacted with aldehydes to give cyanohydrin carbonates. The stereochemistry of this process is predominantly determined by the stereochemistry of the titanium(salen) catalyst and the stereochemistry of two of the cyanohydrin carbonates was confirmed by X-ray crystallography. In a further extension of the chemistry, a homogeneous
Cyanide ion cocatalysis in Ti(salen) catalysed asymmetric cyanohydrin carbonate synthesis
作者:Yuri N. Belokon、Eisuke Ishibashi、Hiroshi Nomura、Michael North
DOI:10.1039/b602156e
日期:——
cocatalyst, 1-2 mol% of titanium(salen) complex catalyses the asymmetric addition of achiral cyanoformates to aldehydes, giving cyanohydrin carbonates with high enantiomeric excesses; and catalyses the diastereoselective addition of chiral cyanoformates derived from alpha-methylbenzyl alcohol to aldehydes, a reaction which exhibits double asymmetric induction.
Synthetic and mechanistic studies on asymmetric cyanohydrin synthesis using a titanium(salen) bimetallic catalyst
作者:Yuri N. Belokon'、A. John Blacker、Paola Carta、Lisa A. Clutterbuck、Michael North
DOI:10.1016/j.tet.2004.07.098
日期:2004.11
A bimetallic titanium(salen) complex 1 was found to catalyse the asymmetric addition of ethyl cyanoformate to aldehydes. Best results were obtained using 5 mol% of the catalyst at −40 °C and under these conditions, both aromatic and aliphaticaldehydes were converted into cyanohydrin carbonates with up to 99% enantiomeric excess. The same catalyst could also be used to catalyse the asymmetric addition
Catalytic, Asymmetric Synthesis of Cyanohydrin Ethyl Carbonates
作者:Yuri N. Belokon'、A. John Blacker、Lisa A. Clutterbuck、Michael North
DOI:10.1021/ol035828f
日期:2003.11.1
The bimetallic titanium complex [(salen)TiO](2), where salen is the ligand derived from (R,R)-cyclohexanediamine and 3,5-di-tert-butyl-salicylaldehyde, has been shown to catalyze the asymmetric addition of ethyl cyanoformate to aldehydes leading to cyanohydrin carbonates with high enantiomeric excesses.