A. Gaucher, J. Ollivier, J. Marguerite
May 1, 1994
Citations
0
Influential Citations
35
Citations
Journal
Canadian Journal of Chemistry
Abstract
(3R)-2-(N-Benzylideneamino)-4-chloro-3-methylbutyronitrile 3, prepared from the commercially available methyl (2S)-3-hydroxy-2-methyl propionate 5 (96% ee), readily underwent potassium carbonate induced cyclization to provide, after acid hydrolysis (6 N HCl) and chromatography, the (1S,2S)-norcoronamic acid 1a with 88% diastereoselectivity and > 95% enantiomeric excess. From (2R)-2-(hydroxymethyl)butyl acetate 23 (> 88% ee) obtained by enzymatic enantioselective hydrolysis with lipase PS, was prepared the (3S)-2-(N-benzylideneamino)-3-(chloromethyl)valeronitrile 29, which after base-induced cyclization (K2CO3) and acid (6 N HCl) or basic (0.8 N NaOH) hydrolysis led to the non-natural (1R,2R)-coronamic acid 18 (> 88% ee). Also from this same acetate (2R)-23 was prepared the (3R)-3-(chloromethyl)-2-[(diphenylmethylene)amino]pentanenitrile 37, which provided the (1S,2S)-coronamic acid 17 (> 88% ee) after base-induced cyclization (K2CO3 or LDA) and acid hydrolysis (6 N HCl). It is noteworthy that these short ...