Visible-Light-Induced EDA Complex Driven Synthesis of Glycosides

Abstract Photoredox-mediated organic transformations represent a powerful green synthetic strategy because they are environmentally compatible and have the advantage of operational simplicity and high chemoselectivity, which allows extensive applications in the fields of organic, synthetic, and carbohydrate chemistry. Photocatalyzed glycosylation methods rely on costly external photocatalysts or organic dyes to generate glycosyl radicals, raising concerns about expense and residual metal contamination, especially in pharmaceutical synthesis. Electron donor-acceptor (EDA) complexes (also called charge-transfer (CT) complexes), where an electron-rich substrate associates with an electron-accepting molecule generating a new molecular aggregate in the ground state, have been extensively studied. Focusing on the recent literature, this chapter presents the basics of photochemistry and the advances in understanding EDA-complex reactions, which has become a cutting-edge approach for harnessing visible light in radical-based synthetic chemistry. The pursuit of greener methods that eliminate the use of photocatalysts has motivated chemists to explore this fascinating area of research. The aim of this chapter is to cover the recent advances in the field of sugar chemistry facilitated by the photoactivity of EDA complexes.