Epoxidation of Olefins Catalyzed by Sulfate-based Supramolecular Ion Pairs

The development of inexpensive and effective catalysts for the epoxidation of olefins to epoxides, which are key commodities for the chemical industry, is a continuing challenge. In this context, we present a supramolecular solution with the development of new host-guest assemblies of sulfate ions and amidoammonium receptor cations that, for the first time, are shown to act as catalysts for olefin epoxidation by hydrogen peroxide under biphasic conditions. Analysis of the reaction mechanism shows that the reactive and oxidizing peroxymonosulfate is formed in the organic phase. Furthermore, a variety of readily available precursors may be used to form the supramolecular ion pairs (SIPs), which is enabling a large-scale synthesis of the catalysts while maintaining catalytic control and effectiveness. Supramolecular host-guest assemblies of sulfate ions and amidoammonium receptor cations are shown to act as catalysts for olefin epoxidation by hydrogen peroxide under biphasic conditions, showing the first case of sulfate ions being used as catalyst by conversion to peroxymonosulfate.image