Racemization of chiral sulfoxide using an immobilized oxovanadium catalyst

Abstract Racemization of optically active compounds is an essential process in asymmetric transformations such as dynamic kinetic resolution and deracemization. In this study, the racemization of chiral sulfoxides under mild thermal conditions was realized using a novel silica-gel-supported oxovanadium catalyst. Specifically, we screened reaction conditions, analyzed the substrate scope, and conducted mechanistic studies of the silica-gel-supported oxovanadium-catalyzed racemization of sulfoxides. The racemization reaction has a wide substrate scope, including alkyl aryl sulfoxides and diaryl sulfoxides. The catalyst could be reused by exploiting its heterogeneous nature. Mechanistic studies suggested that racemization proceeds via the formation of a radical cation intermediate mediated by the oxovanadium(V)/(IV) redox cycle.