Iridium Complex-Catalyzed Pauson-Khand-Type Reaction of Allenynes

Abstract
Vaska’s complex [IrCl(CO)(PPh3)2] efficiently catalyzes the intramolecular carbonylative [2+2+1] cycloaddition of allenynes. A dimethyl substituent on the allene terminus and a low partial pressure of carbon monoxide realize the selective engagement of the internal π-bond of allene.