PREPARATION OF 1-PYRIDINYLETHANOLS OF HIGH ENANTIOMERIC PURITY BY LIPASE-CATALYZED TRANSESTERIFICATIONS

Component B lipase of the Candida antarctica yeast displays high enantioselectivity in catalysing transesterification reactions in non-aqeuous media with chiral secondary alcohols. This was exploited to resolve racemates of 1-(pyridinyl)-ethanols, 1-(6-bromopyridin-2-yl)ethanol, and 1-(6-bromopyridin-2-yl)-2,2-dimethylpropanol. The lipase esterified the (R)-alcohols of the first four substrates in greater than or equal to 99% enantiomeric excess in less than three hours with 30-40% isolated yield. Remaining (S)-enantiomers were isolated in similar yields and in 97-98% ee. 1-(6-Bromopyridin-2-yl)-2,2-dimethylpropanol did not form any detectable ester in one week.