Advances in Photocatalytic Organic Synthetic Transformations in Water and Aqueous Media

Abstract

Advances in visible light-photocatalyzed preparative synthetic organic transformations in water or aqueous media are studied. Both the convenience of visible light photocatalytic strategies to achieve synthetic organic transformations and the employment of water or aqueous mixtures make this approach a very resourceful methodology. Mechanistic aspects for such photocatalyzed processes are discussed. The effects of water in the stereoselectivity of some reactions and considerations regarding the improved enantioselectivity in chiral catalytic photoredox reactions are manifested with the use of water. The use of water as a result of a protocol improvement or environmentally friendlier methodology as compared to the same reaction performed in organic solvents are also considered. All these combined effects of water as a reaction medium or its very presence in photocatalytic reactions have an ultimate goal which is to diminish the environmental impact of synthetic and photocatalytic processes. This perspective highlights the progress and state of the art organic transformations realized by photocatalytic techniques in water or aqueous systems as well as water as a reactant. In this regard, aromatic substitution reactions, radical additions to carbon–carbon double bonds, photooxidation reactions, decarboxylation processes, and miscellaneous reactions are presented.