2020-01-18 08:40:12   来源:

4-叔丁基-2,6-二甲基苯基三氟化硫(FLUOLEADTM)是由日本科学家Umemoto第一次报道使用,它是一种新颖的亲核氟化试剂。相对于现存的氟化试剂,如DAST等液体试剂,FLUOLEADTM是一个固体试剂,有着更好的热稳定性,可以在空气中很容易处理,与水反应缓慢,反应条件温和,能够容忍多种官能团的存在,具有很广的适用范围和很好的选择性。它可以氟化羟基或者是羰基,也可以氟化丙硫酮或着硫酯,甚至可以将羧基(-COOH)转换为三氟甲基(-CF3)。FLUOLEADTM在反应过程中会产生氢氟酸,可以在反应体系中氟化钠,吸收反应中的氢氟酸形成氟化钠氢氟酸盐,通过过滤可以除去。4-叔丁基-2,6-二甲基苯基磺酰氟(ArS(O)F)也是反应中主要的副产物,为了除去这一副产物,可以在反应液浓缩后加入稀的氢氧化钠水溶液(~1.0 M),使得这一副产物水解成钠盐,溶于水中而得以除去。

To a solution of FLUOLEAD (11.7 g, 46.9 mmol) and Et3N·3HF (7.56 g, 7.68 mL, 46.9 mmol) in anhydrous CH2Cl2(75 mL) at 0 °C was added dropwise a solution of 2-phenylprop-2-en-1-ol (5.03g, 37.5 mmol) in anhydrous CH2Cl2 (75 mL). The mixture was then warmed to r.t. and stirred for 6 h (TLC monitoring). sat. aq K2CO3(190 mL) was then slowly added, the mixture was additionally stirred for 1 h, and then extracted with CH2Cl2 (3 × 120 mL). The combined organic layers were dried (MgSO4) and concentrated under reduced pressure. The residue was purified by column chromatography (silica gel, PE 30-40)gave (3-fluoroprop-1-en-2-yl) benzene (3.37 g, 66%).

(JustynaWalkowiak et al. Synthesis,2010, 11, 1883-1890)

FLUOLEAD (2.378 g, 9.5 mmol) and 4-ethoxycarbonyl-1-cyclohexanone (0.851 g, 5 mmol) were placed in a fluoropolymer vessel and dissolved in 10 ml of dry dichloromethane under nitrogen atmosphere. A catalytic amount (2 mmol) of ethanol was added to generate HF. The reaction mixture was stirred at room temperature for 24 h and poured in a saturated sodium bicarbonate solution. The mixture was stirred well, and then the organiclayer was separated, washed with water, dried over anhydrous magnesium sulfate, and filtered. Removal of solvent at reduced pressure gave a residue, which was distilled at reduced pressure to give the product as a colorless liquid (0.816 g, 85%). Its 19F NMR shows that it was a 97:3 mixture of 4-ethoxycarbonyl-1,1-difluorocyclohexaneand 4-ethoxycarbonyl-1-fluoro-1-cyclohexene.