Optical resolution of (+/-)-1-aryl-1-alkanols using enantioselective transesterification by lipases

Enantioselective transesterification of 1-phenyl-1-alkanols (PhCH(OH)(CH2)( n-2)CH3; n = 2, 3, 4, 5, 6, 9, 12, 18) with vinyl acetate catalyzed by lipa ses in benzene has been studied to find the catalyst which is generally use d for preparing optically active 1-phenyl-1-alkanols having various alkyl c hains. Amongst lipases examined (lipases LTP, PS, AK, CAL and RML), the lip ase from Pseudomonas aeruginosa (LIP) is the best catalyst which shows high reactivity and enantioselectivity and low substrate specificity The rate o f the LIP-catalyzed transesterification decreases with increasing the alkyl -chain length till n = 4. The catalysis of LIP recovers again toward the al kanols with n = 5-18. Other lipases do nut exhibit such an effect of alkyl- chain length and show very poor or no catalysis for the alkanols with n gre ater than or equal to 4. LIP is also the best catalyst for the enantioselec tive transesterification of 1-(1-naphthyl)-, 1-(2-naphthyl)- and 1-(1-pyren yl)-1-propanols. Each optically pure 1-aryl-1-alkanol was isolated by the p resent method.