Dirhodium caprolactamate and tert-butyl hydro- peroxide – a universal system for selective oxidations

Oxidations with tert-butyl hydroperoxide (TBHP) catalyzed by dirhodium caprolactamate [Rh₂(cap)₄] provide mild and selective protocols for the oxidative Mannich reaction, conversion of secondary amines to imines, dearomatization of 4-substituted phenols, and oxyfunctionalization of allylic, benzylic, and propargylic positions. The dirhodium catalyst in combination with TBHP is a convenient platform for mechanistic investigations, and their uses point to a variety of directions for the future evolution of the field.