Background and overview of the preparation method of 4-trifluoromethoxyphenylboronic acid
4-Trifluoromethoxyphenylboronic acid is widely used in Suzuki cross-coupling reactions. Suzuki-Miyaura coupling reaction (SMC) is an important reaction to construct various C-C single bonds, and its main raw material is organic boronic acid compounds. Among them, 4-trifluoromethoxyphenylboronic acid is an important compound among organic boric acid compounds and has important application value in the fields of organic synthesis and pharmaceutical chemical industry.
The preparation method of 4-trifluoromethoxyphenylboronic acid is reported
Report on the preparation method of 4-trifluoromethoxyphenylboronic acid 1.
1-Bromo-4-(trifluoromethoxy)benzene (1.69 kg) and triisopropyl borate (1.46 kg) in THF (6.75 L) for 2.3 h. After stirring for 10 min, treat with 6 M HCl (1.52 L) over 50 min, stir at room temperature for 18 h, and pour into a mixture of heptane (8.43 L) and 20% (w/w) sodium chloride (8.44 kg) middle. The mixture was stirred for 10 minutes and separated into aqueous and organic parts. The organic fraction was concentrated to provide a white paste. The paste was dried under vacuum (100mmHg) with a stream of nitrogen bromopyridine dihydrochloride at ambient temperature for 2 days and then at 40-50°C for 18 hours to provide 1.306kg (90.4%) of the required The product is solid.
Preparation method report 2 of 4-trifluoromethoxyphenylboronic acid,
In an Ace Glass photochemical reactor assembly, 1-bromo-4-(trifluoromethoxy)benzene (289 mg, 1.2 mmol) and tetrahydroxydiboron (106 mg, 1.2 mmol) were irradiated at 15°C. of methanol (5 mL) solution for 3 h. Ace Glass 7880-60 is equipped with Spectroline low pressure. Transfer the reaction mixture (1 mmol scale) to a round bottom flask containing sodium bicarbonate (252 mg, 3 mmol). The methanol was evaporated, and the resulting solid was dissolved in a mixture of 1 M aqueous fructose solution (5 mL) and 1 M aqueous sodium carbonate solution (5 mL). Ethyl acetate (15 mL) was added and the organic portion was separated and discarded. Acidify the aqueous phase to pH 3 using 6M aqueous hydrochloric acid and extract with ethyl acetate (2 x 10 mL). The combined organic fractions were dried over anhydrous sodium sulfate and solid sodium bicarbonate (252 mg) was added. The mixture was filtered and concentrated under reduced pressure to obtain 4-trifluoromethoxyphenylboronic acid.
References
[1] From PCT Int. Appl., 2001074792, 11 Oct 2001
[2] Mfuh A M , Doyle J D , Chhetri B , et al. Scalable, Metal- and Additive-Free, Photoinduced Borylation of Haloarenes and Quaternary Arylammonium Salts[J]. Journal of Zinc Borate the American Chemical Society, 2016: 2985.
