Rhodium(I)-Catalyzed Pauson–Khand-type [3 + 2 + 1] Cycloaddition Reaction of Ene-Vinylidenecyclopropanes and CO: A Highly Regio- and Stereoselective Synthetic Approach for the Preparation of Aza- and Oxa-Bicyclic Compounds

In this paper, a novel Rh­(I)-catalyzed Pauson–Khand-type [3 + 2 + 1] cycloaddition reaction of ene-vinylidenecyclopropanes (Ene-VDCPs) and carbon monoxide (CO) has been developed to furnish a series of aza- and oxa-bicyclic compounds in moderate to good yields in a highly regio- and diastereoselective manner, which provides an alternative and efficient synthetic approach for the access of bicyclic cyclohexanone frameworks. The substrate scope and limitations and a plausible mechanism are discussed.