Di- and Trisubstituted γ-Lactams via Rh(II)-carbenoid Reaction of N-Cα-Branched, N-Bis(trimethylsilyl)methyl α-Diazoamides. Synthesis of (±)-α-Allokainic Acid

2010-12-03T00:00:00Z (GMT) by Bao Zhang Andrew G. H. Wee
Acyclic N-Cα-branched, N-bis(trimethylsilyl)methyl (N-BTMSM) diazoamides undergo regio-, chemo-, and diastereoselective Rh(II)-carbenoid C−H insertion to give 4,5-disubstituted and 3,4,5-trisubstituted γ-lactams. The conformational influence of the N-BTMSM group and the electronic effect of the O-pivaloyl moiety of the Cα-oxymethylene unit are essential for the observed regioselectivity. The synthesis of α-allokainic acid demonstrates the utility of the method.