Microbial hydroxylation of unsaturated, cyclic carboxylic acids protected as benzoxazoles

Microbial hydroxylation of 2-(cyclohent-1-enyl)benzoxazole (1) and 2-(cyclo hex-1-enyl)benzoxazole (2) by Cunninghamella blakesleeana DSM 1906 and Baci llus megaterium DSM 32, respectively, gave chiral allylic alcohols 3-(benz- 1,3-oxazol-2-yl)cyclopent-2-en-1-ol (3) and 3-(benz-1,3-oxazol-2-yl)cyclohe x-2-en-1-ol (4) along with achiral ketones 3-(benz-1,3-oxazol-2-yl)cyclopen t-2-en-1-one (5) and 3-(benz-1,3-oxazol-2-yl)cyclohex-2-en-1-one (6). Both allylic alcohols were produced in enantiomeric excesses higher than 99%. Th e determination of their absolute configurations (S in both cases) is descr ibed. (C) 2001 Elsevier Science B.V. All rights reserved.