High‐Valent Copper Catalysis Enables Regioselective Fluoroarylation of Gem‐Difluorinated Cyclopropanes

Abstract

Transition‐metal (TM) catalyzed reaction of gem‐difluorinated cyclopropanes (gem‐DFCPs) has drawn much attention recently. The reaction generally occurs via the activation of the distal C─C bond in gem‐DFCPs by a low‐valent TM through oxidative addition, eventually producing mono‐fluoro olefins as the coupling products. However, achieving regioselective activation of the proximal C─C bond in gem‐DFCPs that overcomes the intrinsic reactivity via TM catalysis remains elusive. Here, a new reaction mode of gem‐DFCPs enabled by high‐valent copper catalysis, which allows exclusive activation of the congested proximal C─C bond is presented. The reaction that achieves fluoroarylation of gem‐DFCPs uses NFSI (N‐fluorobenzenesulfonimide) as electrophilic fluoro reagent and arenes as the C─H nucleophiles, enabling the synthesis of diverse CF3‐containing scaffolds. It is proposed that a high‐valent copper species plays an important role in the regioselective activation of the proximal C─C bond possibly via a σ‐bond metathesis.