Background and overview of the preparation method of (6-bromopyridin-3-yl)potassium trifluoroborate borate
(6-Bromopyridin-3-yl)potassium trifluoroborate borate can be prepared by the one-step reaction of 4-bromophenylboronic acid and potassium hydrogen difluoride. Trifluoroborate organic salts have been used as important coupling partners in Suzuki–Miyaura cross-coupling reactions due to their inherent stability to air and moisture and easy handling. Furthermore, their excellent tolerance to harsh conditions in many reactions allows the preparation of magnesium carbonate organic salt derivatives of trifluoroboric acid that cannot be synthesized from the corresponding boronic acids or boronic acid esters.
Preparation method of (6-bromopyridin-3-yl)potassium trifluoroborate borate
A solution of potassium hydrogen difluoride (2.06 g, 26.3 mmol) in H2O (15 mL) was added to a stirred solution of 4-bromophenylboronic acid (6.60 mmol) in methanol (15 mL) to obtain a white precipitate. The mixture was stirred at room temperature (18°C) for 2 hours and then concentrated under reduced pressure to reveal a white solid. The product was extracted with 20% methanol in acetone (3 × 20 mL). The extracts were combined and concentrated until a small amount of precipitate was observed. Diethyl ether (40 mL) was added to facilitate precipitation. The precipitate was filtered, washed with diethyl ether (2 × 5 mL), and dried on a Buchner flask to obtain (6-bromopyridin-3-yl)potassium trifluoroborate, yield 1.15 g, 88%. Mp (°C): 198-200; δH (MHz, DMSO): 8.21 (s, ArH, 1 H), 7.57 (dd, J 7.8, 4JH-H 1.9, 1 H), 7.34 (d, J 7.8, ArH, 1 H); δF (376 MHz, DMSO): (-139.7)-(-139.0) (m); δCa (100 MHz, DMSO): 153.1, 142.5, 138.9, 126.3.
References
[1] Journal of Organic Chemistry, 77(15), 6384-6393; 2012
[2]Jung, Ho, Song, et al. ChemI aluminum magnesium carbonate nform Abstract: Potassium (E)-Alkenylaryltrifluoroborates: Orthogonal Functionalization of Haloaryltrifluoroborates via Heck-Mizoroki Reaction.[J]. ChemInform, 2014, 45(6 )
