Synthesis of 2-(heteroarylthiomethyl)-1.BETA.-methylcarbapenem via propargylation of 4-acetoxy-2-azetidinone with 3-methyl-1-tributylstannylallene.

Abstract

The key intermediate in the synthesis of 1β-methylcarbapenem, (3S, 4R)-3-[(1R)-1-(tert-butyldimethylsilyloxy)ethyl]-4-[(1S)-1-methyl-2-propynyl]-2-azetidinone (5β), was prepared by propargylation of (3R, 4R)-4-acetoxy-3-[(1R)-1-(tert-butyldimethylsilyloxy)ethyl]-2-azetidinone (3) with 3-methyl-1-tributylstannylallene (4) in the presence of a Lewis acid and successfully converted to a novel 2-(heteroarylthiomethyl)-1β-methylcarbapenem (2).