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

ABSTRACT

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.