Recent Advances of Hypervalent Iodine(III) Reagents upon Visible Light Irradiation

Hypervalent iodine reagents have attracted much attention from organic synthetic chemists. Compared to the strong oxidizing iodine(V) reagents, iodine(III) reagents show a weaker oxidizing ability, which could meet green and environmentally-friendly properties. Over the past decade, visible-light-induced photoredox catalysis has merged as a powerful tool in organic synthetic methodology, and a rapid development was witnessed. It is worth noting that some iodine(III) reagents which are stable and easily available, have been widely utilized in visible light photocatalytic reactions. Particularly, benziodoxol(on)e reagents, due to their excellent activation properties, which can serve as oxidant, radical acceptor, radical precursor and co-catalyst in photocatalytic reactions, allow for many significant chemical transformations. Additionally, phenyliodine(III) diacetate and its derivatives can proceed similar pathway in photocatalytic reactions. These issues attribute to the highly polarized I—X bond of iodine reagents, leads to their oxidizing ability and superior electrophilicity. Herein, some significant advances since in 2016 are summaried and discussed in terms of chemical transformations and mechanisms of different iodine(III) reagents. In addition, the application prospects in the future are also discussed.