Synthesis of the 1β-Methylcarbapenem Key Intermediates

The 1β-methylcarbapenem antibiotics represented by 3, 4, and 5, have been the focus of current synthetic endeavor due to prominent antibacterial activities and broad spectra as well as enhanced chemical and metabolic stability. Progress of the syntheses of 1β-methylcarbapenem key intermediates represented by 6, are reviewed based on the synthetic methods of the characteristic 1β-methyl substituent involved in the contiguous four chiral centers of 6.