Synthetic Studies of Carbapenem and Penem Antibiotics. VI. Stereoselective Reduction of Enamino Ketone and Lactonization of the Reduction Product for the Synthesis of 1β-Methylcarbapenem

The synthesis of the 1β-methylcarbapenem key intermediate 2 from the enamino ketone 6 was investigated. Stereoselective reduction of 6 and effective lactonization of the crude reduction product are described. The methyl group in 6 was shown to play an important role in these steps.