Enantioconvergent transformation of racemic cis-beta-alkyl substituted styrene oxides to (R,R) threo diels by microsomal epoxide hydrolase catalysed hydrolysis

Both enantiomers of cis-beta-ethyl, beta-n-propyl, beta-n-butyl, and beta-n-hexyl substituted styrene oxides undergo microsomal epoxide hydrolase catalysed hydration at the (S) carbon to give the corresponding (R,R) three diols in a > 90% e.e. A complete kinetic resolution of the racemic epoxide is also obtained with the beta-ethyl substituted substrate, but not with its higher homologues.