Aldehydes and ketones as dipolarophiles: application to the synthesis of oxapenams
Abstract
2-Substituted (6a–e) and 2, 2-disubstituted oxapenams (6f–g) are obtained in one step by thermolysis of the β-lactam-based oxazolidinone 4 in the presence of aldehydes and reactive ketones respectively; the C(6)-substituted oxazolidinone variant 7 reacts with hexafluoroacetone to give the enantiomerically pure oxapenam 8.