beta -lactams containing an alpha -exocyclic double bond

摘要

A process is described for selectively obtaining 1- beta -methylcarbapenem intermediates. The desired chirality is obtained through the hydrogenation of certain bicyclic beta -lactam ring structures containing an exocyclic methylene double bond alpha to the beta -lactam ring, in the presence of a Group VIII metal hydrogenation catalyst. The hydrogenation results in a mixture of alpha - and beta -methyl epimers having a high beta / alpha epimeric ratio. New 1- beta -methylcarbapenem intermediates made by the process are also described.