posted on 2002-06-29, 00:00authored byJennifer A. Townes, Michael A. Evans, Jerome Queffelec, Steven J. Taylor, James P. Morken
Iridium-catalyzed reductive coupling of acrylates and imines provides trans β-lactams with high diastereoselection. The optimal catalyst allows
for the synthesis of trans β-lactams bearing aromatic, alkenyl, and alkynyl side chains. This reaction appears to proceed through a reductive
Mannich addition−cyclization mechanism. Examination of substituent effects reveals a linear Hammett correlation for both the N-aryl group on
the imine and the aryloxy group on the acrylate, thereby pointing to rate-determining cyclization in the reaction mechanism.