Tris(pentafluorophenyl)silyl triflate: Synthesis and silylation of carbonyl compounds

Tris(pentafluorophenyl)silyl triflate (1) was prepared by protodesilylation of phenyl-, allyl-, and isopropenyloxytris (pentafluorophenyl)silyl derivatives and characterized by X-ray crystallography. This reagent was employed for the silylation of carbonyl compounds. Aldehydes and ketones afforded the corresponding silyl enol ethers in good yields, while silylation of esters and lactones was dependent on the reaction conditions and on the substrate. A mechanism accounting for the observed phenomena is proposed. Studies of the relative reactivities of 1 and trimethylsilyl triflate are also presented. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).