Achiral dihydroxylation of olefins by osmate (OsO₄^2-) stabilised on nanocrystalline magnesium oxide

Abstract

A recoverable and reusable new heterogeneous AP-Mg-OsO₄ catalyst was designed and developed for the first time via a counterionic stabilisation of OsO₄^2- with Mg²⁺ present on the corner or edge of nanocrystalline MgO. AP-Mg-OsO₄ catalysed the dihydroxylation of olefins to afford diols with excellent yields in the presence of N-methylmorpholine N-oxide for the first time. The absence of osmium and no progress of the dihydroxylation reaction with the filtrate samples withdrawn periodically during the reaction rule out the leaching of osmium unambiguously and provide evidence for the heterogeneity of the reaction. Identification of surface intermediate species by XPS and TGA-DTA-mass thermography gives an insight into the mechanism of the dihydroxylation reaction.