Visible-Light Photoredox Catalysis in Water.

The use of water in organic synthesis draws attention to its green chemistry features and its unique ability to unveil unconventional reactivities. Herein, literature about the use of water as a reaction medium under visible-light photocatalytic conditions is summarized in order to highlight challenges and opportunities. Accordingly, this Synopsis has been divided into four different sections focused on (1) the unconventional role of water in photocatalytic reactions, (2) in -/ on- water reactions, (3) water-soluble photocatalysts, and (4) photomicellar catalytic systems.