Microbiologically Catalyzed Enantio- and Diastereoselective Oxidation of Chrysanthemol Stereoisomers to Chrysanthemic Acids

Abstract

The diastereo- and enantioselective microbial oxidation of a mixture of racemic cis/trans -chrysanthemols to the corresponding stereoisomeric chrysanthemic acids by Aspergillus species is described. Of the three microorganisms which were found capable of oxidizing racemic cis/trans -chrysanthemols, A. ochraceus ATCC 18500 showed complete enantioselectivity for (+)-stereoisomers [(+)- trans -chrysanthemol and (+)- cis -chrysanthemol), whereas A. flavipes ATCC 1030 and ATCC 11013 showed complete enantioselectivity for the (+)- cis -chrysanthemol but a time-dependent enantioselectivity during oxidation of trans -chrysanthemol [oxidation of (+)- trans -chrysanthemol prior to (−)- trans -chrysanthemol]. The diastereoselectivity of all three microorganisms was time dependent, in that the trans -stereoisomers were oxidized prior to the cis -isomers.