Dual Cobalt and Photoredox Catalysis Enabled Intermolecular Oxidative Hydrofunctionalization

A general
protocol has been developed for the Markovnikov-selective
intermolecular hydrofunctionalization based on visible-light-mediated
Co/Ru dual catalysis. The key feature involves the photochemical oxidation
of an organocobalt­(III) intermediate derived from hydrogen atom transfer,
which is supported by electrochemical analysis, quenching studies,
and stoichiometric experiments. This redox process enables the efficient
branch-selective alkylation of pharmaceutically important nucleophiles
(phenols, sulfonamides, and various N-heterocycles) using a wide range
of alkenes including moderately electron-deficient ones. Moreover,
light-gated polar functionalization via organocobalt species was demonstrated.