Structure-dependent selective O- or C-trifluoroethylation of 1,3-dicarbonyls by mesityl(2,2,2-trifluoroethyl)iodonium triflate

Abstract Reaction of [ArICH 2 CF 3 ][OTf] with structurally diversified 1,3-dicarbonyls and an appropriate base at room temperature gave O -trifluoroethylated products, C -trifluoroethylated products, or a mixture of O - and C -trifluoroethylated products in good yields. The product type was dramatically dependent upon the structure of the starting 1,3-dicarbonyls in this reaction. The cyclic 1,3-diketones exclusively afforded the O -trifluoroethylated products, whereas the acyclic 1,3-diketones, β -keto esters, and malonates selectively or specifically formed the C -trifluoroethylated products. Li 2 CO 3 facilitated the C -trifluoroethylation of acyclic 1,3-diketones and β -keto esters. The reaction proceeded under mild conditions, without pre-activation of 1,3-dicarbonyls and use of strong base, and demonstrated a catalyst-free structure-dependent regioselective trifluoroethylation of 1,3-dicarbonyls by mesityl(2,2,2-trifluoroethyl)iodonium triflate.