Copper(I)-catalyzed addition of trifluoromethylated benzyl radicals derived from aryltrifluoroethyl bromides to terminal olefins

Relatively unreactive aryltrifluoroethyl bromides were reacted with 1-octene in the presence of CuCl and 2,2′-bipyridyl at high temperatures. Trifluoromethylated benzyl radical was generated, and a diastereomer mixture of radical adducts was obtained with a (60-70):(40-30) diastereomer ratio. Ph₃SnH reduction of the adducts gave the corresponding hydrocarbons with an isolated trifluoromethyl group. The reactions with styrene or aromatic and aliphatic silyl enol ethers led to the formation of trifluorodiphenylbutene and β-trifluoromethylated ketones, respectively.