Stereoselective Construction of Spiro-Fused Tricyclic Frameworks by Sequential Reaction of Enynes, Imines, and Diazoalkenes with Rh(I) and Rh(II) Catalysts

Stereoselective construction of spiro-fused tricyclic compounds from enynes having a tethered imine with diazoalkenes was achieved by Rh­(I)- and Rh­(II)-catalyzed sequential reactions. This method consists of three reactions, i.e., Rh­(I)-catalyzed cyclization of enynes with a tethered imine, Rh­(II)-catalyzed cyclopropanation with diazoalkenes, and Cope rearrangement. Notably, the sequential reactions can be operated in one pot, in which Rh­(I) and Rh­(II) catalysts work in relay without any serious catalyst deactivation to afford the spirocycles in a stereoselective manner.