A Novel Heterocumulenic Pauson-Khand Reaction of Alkynylcarbodiimides: A Facile and Efficient Synthesis of Heterocyclic Ring-fused Pyrrolinones

The first examples of the heterocumulenic Pauson-Khand reaction are described. Alkynylcarbodiimides undergo an intramolecular Pauson-Khand cycloaddition upon heating in the presence of Mo(CO) 6 and DMSO to afford 4,5-dihydro-1H-pyrrolo[2,3-b]pyrrolin-2-ones and H-pyrrolo[2,3-b]indol-2-ones.