Mild and Soft Catalyzed Trifluoromethylthiolation of Boronic Acids: The Crucial Role of Water.

The most reactive 2nd generation of trifluoromethanesulfenamides undergoes a copper-catalyzed cross-coupling reaction with boronic acids to afford CF3 S-molecules. Contrary to the previous methods in the literature, no base addition, no heating, and no large excess of reagents are required to obtain good results. Furthermore, a crucial role of a small amount of water to favor this reaction has been demonstrated. This constitutes the mildest described conditions for such a reaction.