Efficient biomimetic catalytic epoxidation of polyene polymers by manganese porphyrins

Two polyene polymers, cis-polybutadiene and cis-polyisoprene, were transformed into polyepoxides under mild conditions. The epoxidation of these two polyene polymers is stereospecific, giving cis-epoxides as products. All factors controlling the reaction rate, such as the nature of the catalyst, the oxygen donor and the presence of bases as axial ligands, were studied. The optimum results were obtained when iodosylbenzene was used as the oxygen donor, Mn(TpFPP)Cl as the catalyst and imidazole as the axial ligand. Under these optimum conditions the turnover number was found to be 71. These results render this system promising for the epoxidation of polyene polymers in a more general way.