Olefin epoxidation catalyzed by ruthenium porphyrins using dioxygen as oxidant

Abstract

RuVI(TDCP)O2 and RuVI(TMP)O2 were synthesized by reacting RuII(TDCP)(CO)(MeOH) and RuII(TMP)(CO)(MeOH) with m-chloroperoxybenzoic acid in dichloromethane. RuVI(P)O2 complexes are effective in epoxisation of olefins. The turnover rates by RuVI(TDCP)O2 are lower than that of corresponding reactions catalyzed by RuVI(TMP)O2. Both catalysts are deactivated after the reaction by the formation of a stable Ru(II) carbonyl species. Kinetics studies showed that the intermediates are cationic 3-membered species. A concerted oxygen insertion mechanism is proposed.