The general procedure for the synthesis of 2-triphenylenylboronic acid from trimethyl borate and 2-bromobenzo[9,10]phenanthrene was carried out as follows: the intermediate E1 (2.90 g, 9.44 mmol) was dissolved in tetrahydrofuran (80 ml) under argon protection and cooled to -78 °C. Subsequently, n-BuLi (1.60 M hexane solution, 6.20 ml, 9.11 mmol) was slowly added and gradually warmed to 0 °C over 2 h. The reaction mixture was then cooled to -78 °C under argon protection. The reaction mixture was again cooled to -78 °C, trimethoxyborane (2.58 g, 24.8 mmol) was added and stirred at -78 °C for 20 minutes before slowly warming to room temperature and continuing to stir for 8 hours. After completion of the reaction, 1M aqueous hydrochloric acid (20 ml) was added and stirred at room temperature for 1 hour. The organic layer was extracted with ethyl acetate, the organic phases were combined and dried with magnesium sulfate. After concentration, the residue was dissolved in hexane and purified by suspension, washing, filtration and recrystallization to give intermediate E2 (1.46 g, 5.38 mmol, 57% yield).
![2-bromobenzo[9,10]phenanthrene](/CAS2/GIF/19111-87-6.gif)
