Highly Enantioselective Iron-​Catalyzed cis-​Dihydroxylation of Alkenes with Hydrogen Peroxide Oxidant via an FeIII-​OOH Reactive Intermediate

Abstract

The development of environmentally benign catalysts for highly enantioselective asymmetric cis-dihydroxylation (AD) of alkenes with broad substrate scope remains a challenge. By employing [FeII(L)(OTf)2] (L = N,N’-dimethyl-N,N’-bis(2-methyl-8-quinolyl)-cyclohexane-1,2-diamine) as a catalyst, cis-diols in up to 99.8% ee with 85% isolated yield have been achieved in AD of alkenes with H2O2 as an oxidant and alkenes in a limiting amount. This “[FeII(L)(OTf)2] + H2O2” method is applicable to both (E)-alkenes and terminal alkenes (24 examples > 80% ee, up to 1 g scale). Mechanistic studies, including 18O-labeling, UV/Vis, EPR, ESI-MS analyses, and DFT calculations lend evidence for the involvement of chiral FeIII-OOH active species in enantioselective formation of the two C=O bonds.