CLEAVAGE OF CHIRAL 4-PHENYL-2-OXAZOLIDINONES WITH TMSI - APPLICATION TO THE SYNTHESIS OF CARBACEPHEMS

A new technique for cleaving chiral N-substituted 4-phenyl-2-oxazolidi nones is described. Thus reaction of 7-[4-phenyl-2-oxazolidinone]-carb acephem with TMSI and HMDS in acetonitrile, followed by DABCO, then aq ueous hydrochloric acid gives the carbacephem nucleus, carbon dioxide, and acetophenone. This method allows a more versatile use of 4-phenyl -2-oxazolidinone as a chiral auxiliary and N-protective group in the s ynthesis of carbacephems.