An Efficient C-Si/C-H Cross-Coupling Reaction Enabled by a Radical Pathway

The methods for the cross-coupling of aryl(trialkyl)silanes are long-standing challenges due to the extreme inertness of C-Si(R3) bond, though the reaction is environmentally friendly and highly regioselective to synthesize biaryls. Herein, we report a copper-catalyzed cross-coupling of aryl(trialkyl)silanes and aryl via a radical mechanism. The reaction proceeds efficiently with aryl sulfonium salts as limiting reagents, exhibits broad substrate scope, and provides an important synthetic strategy to acquire biaryls, exemplified by unsymmetrical fluorescence probes and late-stage functionalization of drugs. Of note, the experimental and theoretical mechanistic studies revealed a radical mechanism where the copper catalyst and CsF play critical roles on the radical generation and desilylation process. The aryl radical from sulfonium salts have been generated through copper-metal-catalyzed processes, which enable the successful biaryl transformation through the addition to the aryl(trialkyl)silanes for the first time. Given the fast development in the copper catalysis, this method is expected to present new opportunities for exploring aryl(trialkyl)silanes in biaryl synthesis. image