Ligand-Enabled Copper-Catalyzed Regio- and Stereoselective Allylboration of 1-Trifluoromethylalkenes.

A copper-catalyzed regio- and stereoselective allylboration of 1-trifluoromethylalkenes with bis(pinacolato)diboron (pinB-Bpin) and allylic chlorides has been developed to form functionalized trifluoromethylated products with high diastereoselectivity. The key to success is the judicious choice of Cs₂CO₃ base and <i>t</i>-Bu-modified dppe-type ligand, which enables the otherwise challenging high catalyst turnover and suppression of the competing defluorination side reaction from an alkylcopper intermediate. The product derivatization of the resulting Bpin moiety can deliver diverse CF₃-containing molecules with high stereochemical fidelity.