Electrochemical hydroxylation of alkenes with H2O

ABSTRACT Alcohol is one of the most prevalent functional groups found in biologically active molecules with unparalleled abundance and structural diversity. The hydroxylation reaction of alkenes represents a convenient approach for synthesizing such molecules. However, a general and direct method featuring a broad substrate scope and good functional group tolerance remains elusive. Herein, we report our efforts in applying electrochemistry to accomplish the hydroxylation of alkenes utilizing H2O as the sole source of hydroxyl without the need for stoichiometric oxidants and strong acidic reagents. This process operates via the formation of a high-valence cobalt(IV) intermediate, which could readily be entrapped by water to deliver the desired alcohol product. Mechanistic studies, cyclic voltammetry analysis and density functional theory calculations have been conducted to verify the feasibility of cobalt valence changes, including the generation of cobalt hydride species, the formation of intermediates following hydrogen atom transfer, the oxidation potential from Co(III) to Co(IV), which substantiate the proposed reaction pathways. Furthermore, the late-stage modification of biorelevant molecules has demonstrated promising potential applications for this approach in synthetic chemistry.