Microbiologically catalyzed enantio- and diastereoselective oxidation of chrysanthemol stereoisomers to chrysanthemic acids.

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.