Copper-Catalyzed Trifluoromethylation of Trisubstituted Allylic and Homoallylic Alcohols

An efficient copper-catalyzed trifluoromethylation of trisubstituted allylic and homoallylic alcohols with Togni's reagent has been developed. This strategy, accompanied by a double-bond migration, leads to various branched CF3-substituted alcohols by using readily available trisubstituted cyclic/acyclic alcohols as substrates. Moreover, for alcohols in which beta-H elimination is prohibited, CF3-containing oxetanes are isolated as the sole product.