A Mild, Nonbasic Synthesis of Thioethers. The Copper-Catalyzed Coupling of Boronic Acids with N-Thio(alkyl, aryl, heteroaryl)imides

A new synthesis of thioethers is described. The reaction of boronic acids with aryl, heteroaryl, and alkyl N-thioimides in the presence of catalytic quantities of a Cu(I) carboxylate affords good to excellent yields of thioethers. This reaction takes place in the absence of a base under mild conditions (THF, 45−50 °C, 2.5−12 h) and represents an interesting complement to known methods for thioether synthesis.