Enantioselective reduction of racemic abscisic acid by Aspergillus niger cultures

Abstract

Biotransformation of racemic abscisic acid [(±)-ABA]1a with cultures of Aspergillus niger gives rise to the enantioselective reduction of the (S)-enantiomer to afford the corresponding (1′S, 2′R)-(–)-2′,3′-dihydro-ABA acid 2a in high enantiomeric excess (e.e.). The structure, stereochemistry, and preferred conformation of compound 2a have been elucidated on the basis of NMR evidence.