New Horizons of Photocatalytic Fluoromethylative Difunctionalization of Alkenes

Radical tri- and difluoromethylation (fluoromethylation) by photoredox catalysis has emerged as a new synthetic methodology over the past several years. In particular, the strategy is useful for the introduction of a fluoromethyl group (CF2X, X = F or H) and a different functional group across a carbon-carbon double bond via a single operation. Step-economical synthesis of diverse organofluorine compounds bearing a C(sp(3))-CF2X bond has been achieved. In this review, the discussion focuses on recent representative examples of photoredox-catalyzed fluoromethylative difunctionalization of alkenes through redox-neutral processes. Close attention is paid to the choice of the fluorome-thylating reagent and the photocatalyst. The basic concept, reaction design, and the prospects for this research area are also discussed.