Chiroporphyrins: An Approach to Asymmetric Catalysts with Stereocenters Near the Plane of the Porphyrin Ring

Readily available chiral aldehydes and pyrrole provide porphyrins like 1 in a single step. Mn-Cl derivatives of such compounds are effective catalysts for the enantioselective epoxidation of nonfunctionalized olefins. The design of chiral porphyrin ligands should receive new impetus, since in the synthesis of 1, the D2-symmetric isomer is formed preferentially, and time-consuming resolution is not necessary.