Palladium catalyzed C(sp3)–H trifluoroethoxylation

Abstract

Palladium(II) complexes of the TPA family (TPA − tris(2-pyridylmethyl)amine) have recently emerged as efficient catalysts of highly 3°-regioselective hydroxylation and chemoselective 2°-ketonization of aliphatic C–H groups with peroxycarboxylic acids. Herewith, we present a novel facet of the catalytic reactivity of such complexes that have been shown to mediate highly efficient (at as low as 0.6 mol. % catalyst loadings) and selective trifluoroethoxylation of organic substrates at benzylic C–H groups, affording the corresponding trifluoroethoxy ethers in up to 73 % isolated yield. The developed synthetic protocol allows for diastereoselective trifluoroethoxylation of complex molecules of natural origin (steroids, terpenoids).