Mechanistic Insights and Kinetic Analysis for the Oxidative Hydroxylation of Arylboronic Acids by Visible Light Photoredox Catalysis: A Metal-Free Alternative

The photocatalytic hydroxylation of boronic acids with methylene blue as photosensitizer proceeds with high efficiency. Detailed time-resolved studies of the relevant rate constants provide a clear mechanistic understanding of excited-state processes and guided the selection of the photocatalyst and the optimization of experimental conditions.