Abstract: | An efficient method for the trifluoromethylation of halogenated double bonds by using in situ generated “trifluoromethyl copper” is described. Herein, the most common trifluoromethyl source, (trifluoromethyl)trimethylsilane, was converted selectively into “trifluoromethyl copper” by using copper iodide as copper source and potassium fluoride as promoter. In 1,3‐dimethyl‐3,4,5,6‐tetrahydro‐2(1H)‐pyrimidinone (DMPU) as chelating solvent the trifluoromethylation of activated and non‐activated alkenyl halides occurred mostly in good to excellent yields in up to a gram scale. |