The studies on the chemoenzymatic synthesis of 2-benzyl-3-butenoic acid

The studies on the chemoenzymatic synthesis of 2-benzyl-3-butenoic acid 3 were performed. The alkylation of dienolates derived from the crotonic and vinylacetic acids with different types of alkylating agents was examined. In all cases the inseparable mixture of isomeric acids 3 and 4 were obtained. Chemoselective enzymatic esterification of those mixtures provides ester 6 in 86% yield as a single product without double bond isomerization. None common method can be used for its hydrolysis since under basic conditions only isomeric acid 5 is formed. To overcome this limitation enzyme catalysed hydrolysis process was design. This protocol afforded isomerically pure acid 3 in 98% yield.