Mg-Prompted Polyfluoroarene C-H Functionalization: Formal Synthesis of Transfluthrin, Fenfluthrin, and Tefluthrin.
Directing group and transition metal free C-H bond functionalization of a simple molecule is an ideal but challenging chemical transformation. Herein, we report a general Mg-prompted approach to synthesize versatile polyfluoroaryl carbinols at ambient temperature via polyfluoroarene C-H bond addition to aldehydes, which featured excellent monoaddition selectivity and broad functional group compatibility. The usefulness of this practical and efficient method was demonstrated in gram-scale formal synthesis of pyrethroid insecticides transfluthrin, tefluthrin, and fenfluthrin.