芳香族直接氟化法一般采用F2-N2體系,對(duì)反應(yīng)容器及反應(yīng)條件控制的要求較高,而且用該方法時(shí)易產(chǎn)生芳環(huán)上二取代或多取代副產(chǎn)物,如要得到一取代為主產(chǎn)物,一般要在芳環(huán)上有一個(gè)強(qiáng)拉電子的定位基團(tuán)(硝基、羰基等)例如:
近年來(lái),隨著氟化學(xué)研究的發(fā)展,出現(xiàn)了一些溫和的氟代試劑(F-TEDA-BF3 SelectfluorTM等),使得芳環(huán)上直接氟代制備芳香單氟代物更簡(jiǎn)單易行,如:
實(shí)例:
Procedure:A solution of the pyrrole compound 1 (0.33 g,2.00 mmol, 1.0 equiv) and Selectfluor? (0.71 g, 2.00 mmol, 1.0 equiv) in MeCN (20 mL) was refluxed in a MLSSTART 1500 microwave synthesizer at 70 to 72 °C for 5 min. The reaction was quenched by addition of 50 mL H2O to the cooled solution followed by the addition of 50 mL CHCl3. The layers were separated and the aqueous phase was extracted with CHCl3 (3 x50 mL). The combined organic phases were dried with MgSO4 and the solvent was removed under reduced pressure, followed by flash column chromatography PE/TBME (15:1) to afforded 2 (0.15 g, 40%) as light yellow oil.
芳環(huán)碳?xì)滏I氟化方法匯總
除了上述方法外,本文我們整理了部分芳環(huán)的其他直接氟化方法,分享給大家,如果有沒(méi)有涉及到的實(shí)用方法,小伙伴們也可以推薦給我們。
來(lái)源:覽博網(wǎng)