Preparation of optically-active alpha-substituted carboxylic esters and acids
申请人:E.I. DU PONT DE NEMOURS AND COMPANY
公开号:EP0116914A1
公开(公告)日:1984-08-29
Optically-active alpha-substituted carboxylic esters are prepared by treating a non-symmetrical ketene with an alcohol in the presence of an optically-active amine catalyst. Hydrolysis of the resulting esters, yields the optically-active acid corresponding to the non-symmetrical ketene.
Process for the preparation of optically-active cyanomethyl esters
申请人:E.I. DU PONT DE NEMOURS AND COMPANY
公开号:EP0291626A2
公开(公告)日:1988-11-23
Stereoisomerically-enriched cyanomethyl esters are prepared by treating a non-symmetrical ketene or an alpha-chiral carboxylic acid halide or reactive derivative thereof with an optically-active alpha-hydroxynitrile. Certain optically-active optionally substituted S-alpha-cyano-3-phenoxybenzyl alcohol intermediates are prepared by treating the corresponding aldehyde or ketone with a source of hydrogen cyanide in the presence of a substantially water-immiscible, aprotic solvent and a cyclo(D-phenylalanyl-D-histidine) as a catalyst.