Hydrochloric Acid → 3-Cyanophenylboronic acid

Participants

Reaction Steps

3-Bromobenzonitrile (10.0 g, 55 mmol) was dissolved in dry THF (100 mL) and cooled to −100° C. (Et2O/N2). n-Butyllithium (24.2 mL, 2.5 M in hexane) was added over 30 minutes, maintaining the internal temp under −90°. After 20 minutes, triisopropylborate (18.0 mL) was added over 15 minutes, again maintaining the internal temperature. After the addition was complete, the reaction was allowed to warm slowly to room temperature over 1.5 hours. The reaction was stirred at room temp for 16 hours, then cooled to 15° C., after which 6 M HCl (25 mL) was added. After stirring vigorously for 3.5 hours, the reaction was partitioned between water and EtOAc. After extracting a second time with EtOAc, the combined organics were washed with 2 M NaOH. The aqueous extract was neutralized with 6 M HCl. The white precipitate was filtered, yielding the desired product (4.80 g, 60%). 1H NMR (DMSO-d6): δ8.37 (s, 2H), 8.10 (s, 1H), 8.03 (dt, 1H, J=7.3, J′=1.1), 7.83 (dt, 1H, J=7.6, J′=1.4), 7.53 (t, 1H, J=7.7).

Provenance & Evidence