A convenient synthesis of polycyclic γ-lactams via Pauson-Khand reaction

Abstract

Pauson-Khand reaction of hydroxyenynes with Co2(CO)8 in the presence of N-methylmorpholine N-oxide or trimethylamine N-oxide as a promoter produced polycyclic γ-lactams as single stereoisomers in moderate to excellent yield. These are the first examples of an intramolecular Pauson-Khand reaction on a hydroxyenyne system tethered to a three- and four-membered ring as new skeletons with 5,6,5 fused ring systems.