Synthesis and Catalytic Epoxidation Activity of Terpene-Derived D4- Symmetric Metalloporphyrins.

Abstract We report here a flexible synthesis of chiral, D4-symmetric porphyrins from cyclic ketone starting materials. Two porphyrins have been synthesized from the terpene 1-R-(+)-nopinone, obviating the need to perform a resolution. The chloromanganese derivative of one of these porphyrins is a good catalyst for the epoxidation of terminal alkenes, providing epoxides with e.e.'s of 70% with high turnover numbers. A predictive model for oxygen atom transfer in the chiral pocket is discussed.