Abstract: The first successful syntheses of several anti-Bredt P-lactams from alkyl acetoacetate in 1 1-14 steps are described. The key cyclization reaction involves the Rh (I1)- catalyzed carbene insertion of the diazo derivatives 12, 23, and 31 into the NH bond of the 0- lactams. These (f)-1, 3-bridged 0-lactams have IR absorptions of 1780-1 795 cm-'for the (3- lactam carbonyls. The structure of 32d has been determined by X-ray crystallography; this ...
