1990年Umemoto報(bào)道了化合物1和2的合成及應(yīng)用，這是第一種親電性的三氟甲基化試劑【 Umemoto, T; Ishihara, S. TetrahedronLett. 1990, 31, 3579】。隨后Umemoto報(bào)道了化合物3和4的合成及應(yīng)用【 (a) Umemoto, T; Ishihara, S. J. Am. Chem. Soc.1993, 115, 2156. (b) Umemoto, T; Ishihara, S; Adachi, K. J. Fluorine Chem. 1995,74, 77】。
這幾個化合物是穩(wěn)定的晶體，具有良好的穩(wěn)定性。苯并環(huán)是很好的離去基團(tuán)，在取代過程中容易離去，有利反應(yīng)進(jìn)行。反應(yīng)易于處理，特別是化合物4，反應(yīng)生成后的磺酸是水溶性的，極易除去。這種三氟甲基化并不是通過CF3＋進(jìn)行，也不是SN2取代，可能是通過SET機(jī)理產(chǎn)生三氟甲基自由基，然后對碳負(fù)離子的親電加成。
這種方法通用型強(qiáng)，通過這種方法，可以在多種親核性化合物（anions of b--diketones, b--keto esters and malonates, acetylideions, silyl enol ethers, enamines, activated aromatics, heteroaromatics,alkane- and arenethiolate anions, halide anions, and various enolate anions）上引入三氟甲基。但這幾個試劑制備困難，價(jià)格較高，限制了其應(yīng)用。
反應(yīng)實(shí)例
【 Umemoto, T; Ishihara, S. TetrahedronLett. 1990, 31, 3579】
【Umemoto, T; Ishihara, S. J. Am. Chem. Soc.1993, 115, 2156】
【Umemoto, T; Ishihara, S; Adachi, K. J. Fluorine Chem. 1995,74, 77】
Under an argon atmosphere, to a solution of Ethynyl-benzene (1.02 g, 10 mmol) was dropped n-BuLi (2.5M, 6 mL, 15 mmol) at –78oC, the mixture was stirred for 1 h, trifluoromethyl onium salt 3 (11 mmol) was added in several portions. Thereaction mixture was stirred for another 1 h at room temperature, then quenchedby saturated NH4Cl solution, and extracted with EA. The combined organic layer was dried over Na2SO4, concentrated under reduced pressure. The residue was purified by column chromatography onsilica gel to give the desired product (0.58 g,58%).
【Umemoto, T; Ishihara, S. J. Am. Chem. Soc.1993, 115, 2156】
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