Synthesis of chiral Mn(III)-meso-tetrakis-[2.2]-p-cyclophanyl-porphyrin: A new catalyst for enantioselective epoxidation

he synthesis of Mn(III)-complexes of new chiral porphyrins 1a and 1b prepared by condensation of enantiomerically pure [2.2]-p-cyclophane-4-carbaldehyde and pyrrole are described. These compounds were used as catalysts in epoxidation reactions of prochiral alkenes, carried out in the presence of aqueous NaOCl at pH = 10.0 as oxygen donor and small amounts of 4-tert-butylpyridine as axial ligand, in CH2Cl2/H2O two-phase conditions at 0 degrees C. Results indicate a satisfactory catalytic efficiency (up to 700 overall turnovers), with enantiomeric excesses in the range 22-31%.