Ligand effects in the Rh(II) catalyzed reaction of α-diazo ketoamides

The rhodium(II) catalyzed decomposition of several α-diazo ketoamides resulted in either formation of a push–pull carbonyl ylide intermediate followed by intramolecular [3+2]-cycloaddition across the tethered π-bond or C–H insertion of the initially formed rhodium carbenoid into the C5-position of the lactam ring followed by a carboethoxy-decarboxylation reaction. The chemoselectivity exhibited by the rhodium carbenoid intermediate was found to be markedly dependent on the metal ligands employed.