Intermolecular rhodium-catalyzed [2 + 2 + 2] carbocyclization reactions of 1,6-enynes with symmetrical and unsymmetrical alkynes

The crossed intermolecular rhodium-catalyzed [2 + 2 + 2] carbocyclization of carbon and heteroatom tethered 1,6-enynes can be accomplished with symmetrical and unsymmetrical alkynes, to afford the corresponding bicyclohexadienes in an efficient and highly selective manner.