to be a versatile intermediate of the carbapenem nuclei on the basis of previous and a combination of enzymatic and chemical procedures was taken as our synthetic strategy. Cohen and Khedouri showed that a-chymotrypsin hydrolyzes the pro-S ester group of diethyl@-acetamidoglutarate. 6 However, the acetamido compound was considered not a good candidate for our purpose, since it may cause difficulty in further hydrolysis of the ...