(-)-Bulgecinine (2) and carbapenems (3) have been synthesized from L-pyroglutamate (1) using as a bifunctional chiron without a prior modification. In the synthesis of (-)-bulgecinine (2), the regioselective enolate of L-pyroglutamate (1) was treated with 2-toluenesulfonyl-3-phenyloxaziridine to furnish (4R)-alcohol (4a). Hydroxylation was highly selective (>98% d.e.) and no racemization was detected. (-)-Bulgecinine (2) was synthesized from the alcohol 4a in 7 steps. The combination of regioselective addition reaction of a ester enolate to the lactam (1) and chirospecific pyrrolidine ring formation of the ester (12) was the main strategy in the synthesis of carbapenems. Various ester enolates gave the mono adduct (12) which on hydrogenolysis followed by hydrogenation at medium pressure gave 2,5-cis pyrrolidine derivative (14) exclusively. The pyrrolidine (14) were converted to carbapenams (15) and then to carbapenems (3).
