G. D. Gamalevich, E. P. Serebryakov
1997
Citations
0
Influential Citations
6
Citations
Journal
Russian Chemical Bulletin
Abstract
Partial acylation of (R,S)-3,7-dimethyloctan-1-ol (1) and (R,S)-7-methoxy-3,7-dimethyloctan-1-ol (2) with vinyl acetate catalyzed by the lipase fromCandida cylindracea affords in good yields the correspondingS-configured acetates with 92–98% enantiomeric excess (ee). Under similar conditions, racemic α-cyclogeraniol (3), drim-7-en-11-ol, methyl 4-(3-hydroxy-2-methylpropyl)benzoate, and its η6-chromium(tricarbonyl) complex (6) are acylated with rather poor (and, for the two latter, opposite) enantioselectivity, whereas (R,S)-2,4∶3,5-di-O-benzylidenexylitol remains unaffected. Racemic isoborneol (8) and 2-nitro-1-phenylethanol also remain almost or completely unconverted. Attempts to perform enantioselective acylation of alcohols 3 and 8 with Ac2O in the presence of porcine pancreatic lipase (PPL) proved equally unsuccessful. By contrast, the PPL-catalyzed acylation of alcohol 6 with vinyl acetate at 17% conversion affords the levorotatory acetate (S)-6a withca. 100%ee. PPL-Mediated partial acylation of (R,S)-pantolactone with Ac2O, followed by mild deacylation of the resultingR acetate, gives (R)-(-)-pantolactone of 97% enantiomeric purity in 60% overall yield.