Visible-light-induced selective defluoroalkylations of polyfluoroarenes with alcohols

To provide alpha-polyfluoroarylalcohols, a novel protocol for the selective defluoroalkylation of polyfluoroarenes with easily accessible alcohols was reported via the cooperation of photoredox and hydrogen atom transfer (HAT) strategies with the assistance of Lewis acids under visible light irradiation. The protocol featured broad scope, excellent regioselectivity for both C-H and C-F bond cleavages, and mild conditions. Mechanistic studies suggested that the reaction occurred through Lewis acid-promoted HAT to provide an alkyl radical and sequential addition to polyfluoroarenes. Impressively, the regioselectivity for C-F cleavage was verified with the Fukui function. The feasibility and application of this protocol on fluoroarene synthesis were well illustrated by gram-scale synthesis under both batch and flow conditions, late-stage decoration of bioactive compounds, and further transformations of the fluoroarylalcohols.

Automated summary

A novel protocol for selective defluoroalkylation of polyfluoroarenes with accessible alcohols was reported using photoredox and hydrogen atom transfer (HAT) strategies with the assistance of Lewis acids under visible light irradiation. The protocol exhibited broad scope, excellent regioselectivity, and mild conditions. Mechanistic studies revealed that the reaction proceeded via Lewis acid-promoted HAT and sequential addition to polyfluoroarenes.