Prakash 試劑（TMSCF3）是非常一種重要的三氟甲基化試劑，可以對羰基化合物進(jìn)行親核取代。此方法是在1984 年由Ruppert 首先報(bào)道，隨后Prakash 對其應(yīng)用做了大量的工作，這是從羰基化合物合成三氟甲基化合物最便捷的方法，反應(yīng)條件溫和，操作方便，產(chǎn)率較高，在有機(jī)合成中的應(yīng)用也很廣泛。
反應(yīng)加入少量氟化物（如TBAF, CsF 等）催化，TMSCF3 對羰基的缺電子碳進(jìn)行親核取代，最后生成三氟甲基取代的化合物，如果是酯作為底物，水解后則生成三氟甲基酮。
反應(yīng)實(shí)例
(Wiedemann, J; Heiner, T; Prakash, G, K, S. Angew. Chem. Int. Ed. 1998, 37, 820)
To the solution of methyl benzoate (1.36 g, 10 mmol) and TMSCF3 (1.78g, 12.5 mmol) in dry toluene (20 mL) was added the initiator anhydrous tetrabutylammonium fluoride (TBAF; 2.5 mol% in THF) -78oC, and the reaction mixture was then allowed to warm slowly to room temperature, stirred for 18 h. The resulting mixture was treated with 2M hydrochloric acid (5 mL), extracted with EA, washed with water and brine, the organic phase was concentrated under reduced pressure. The residue was purified by column chromatography on silica gel to give 1,1,1-trifluoroacetophenone (1.65 g, 95%).
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