Copper-mediated arylation of thioethers with boronic acids.

A copper-mediated Chan-Lam coupling of thioethers with boronic acids is developed for the efficient synthesis of aryl sulfonium salts. The reaction exhibits exceptional functional group tolerance, accommodating free amino and hydroxy groups without protection. This strategy enables late-stage functionalization of complex drug molecules. Meanwhile, the resulting sulfonium salts exhibit tunable UV absorption and thermal stability, suggesting their potential as candidates for further evaluation in photoacid generator applications.