A Facile Chemoenzymatic Route to Optically Active 4, 5-Disubstituted-2E-hexenoate Derivatives. I

The reaction of (±) methyl 4, 5-trans-epoxy-(2E)-hexenoate (1) with nucleophile having heteroatoms in the presence of BF3·Et2 O gave the 4, 5-anti-5-hydroxy-4- and/or 2, 5-anti-5-hydroxy-2-substituted products. Among them, the (±)-4, 5-anti-5-hydroxy-4-thiophenoxy ester 12a was enantioselectively acetylated with acylating reagent in the presence of lipase "PL 266" from Alcaligenes sp. to provide the (4S, 5R)-5-acetoxy ester 12b and (4R, 5S)-12a quantitatively.