Microbial Stereoselective Epoxidation of 2,2-Dimethyl-6-Cyano-3-Chromene

Abstract

The epoxidation of 2,2-dimethyl-6-cyano-3-chromene was achieved using a whole cell biotransformation. A number of microorganisms were studied for the required monooxygenase activity and a few were shown to exhibit high levels of enantioselectivity in producing the corresponding 3,4-(R,R) stereochemistry epoxide. This resulting enantiomerically pure (R,R) product is an intermediate to the (+)-isomer of the antihypertensive agent cromakalim (BRL 34915).

Key Words:

• Chiral epoxidation
• 2,2-dimethyl-6-cyano-3-chromene
• 2,2-dimethyl-6-cyano-3,4-epoxychroman
• cromakalim