The key for establishing this protocol is the distinct ability of the iminophosphorane catalyst to precisely direct the equilibrium mixture of the enediolates toward the intermolecular carbon-carbonbondformation with simultaneous yet rigorous control of relative and absolute stereochemistry. The critical importance of the cyclohexyl substituents on the catalyst backbone in dictating the reaction
A full account of our anionic polycyclization approach to accesshighlyfunctionalizedtricycles related to quassinoids and terpenoids from several optically active bicyclic enone systems and Nazarov reagents is presented. (+)-Carvone is the only chiral source used to fix the entire stereochemistry of all of the tricycles, and the stereochemical outcome of this process was unambiguously determined