Esterase catalysed enantioselective ring closure

Porcine liver esterase catalyses the reaction of gamma-amino esters in wate r to give a mixture of the corresponding gamma-lactam and the hydrolysis pr oduct, deacylation of the acyl enzyme intermediate by ring closure occurs w ith a high enantioselectivity giving an ee of 90% for the formation of (S)- 5-phenyl-2-pyrrolidone from racemic ethyl 4-phenyl-4-aminobutanoate.