STEREOSELECTIVITY OF THE ENZYMATIC REDUCTION OF ALDEHYDIC AND KETONIC CARBONYL GROUPS IN PLANAR CHIRAL ORGANOMANGANESE COMPLEXES

(±)-Tricarbonyl(η5-1-formyl-2-methylcyclopentadienyl)manganese (1) was optically resolved with horse liver alcohol dehydrogenase (HLADH) and two species of yeasts, Saccharomyces sp. H-1 and Rhodotorula rubra IFO 889. Usually, (1R)-1 was preferentially reduced to give (−)-alcohol 2 of ≥ 97% e.e. − 84% e.e. Ketone analogue (±)-tricarbonyl(η5-1-acetyl-2-methylcyclopentadienyl)-manganese (4) was reduced by the yeasts. The major product by S. sp. H-1 was the (1S,2R,1′S)-(+)-alcohol (5) (≥ 98% e.e.) and the minor product, the (1R,2S,1′S)-(−)-alcohol (6) (86% e.e.). R. rubra gave only the latter alcohol (≥ 99 % e.e.). The Stereodifferentiation mechanism for these bioreductions is discussed in terms of the Prelog rule. The mechanism for HLADH reduction was examined with computer graphics. © 1990 by the Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.