Compound 1b

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InChIKey YYBVTXQPQUAKST-VAWYXSNFSA-N

Synthetic procedure: See article for the definitive version of this procedure and for full experimental details.

To a solution of IMe•HCl (34 mg, 0.10 mmol) in THF (0.5 mL) was added KOtBu (11 mg, 0.10 mmol). The solution was stirred at room temperature for 15 minutes before the addition of 2-Bromobenzyl alcohol (935 mg, 5.00 mmol), 4Å molecular sieves (500 mg) and boronate 1a (252 mg, 1.00 mmol) sequentially. The reaction mixture was then heated at reflux for 12 hours before being filtered, concentrated and purified with column chromatography to afford the pure product. The product was further recrystallized from hot chloroform to give the adduct 1b (90 mg, 22%) as a red solid. ¹H NMR (400 MHz, CDCl₃) δ 7.61 (dd, J = 8.0, 1.6 Hz, 1H), 7.46 (ddd, J = 7.6, 2.0, 0.4 Hz, 1H), 7.35 (td, J = 7.6, 1.6 Hz, 1H), 7.22 (td, J = 8.0, 1.6 Hz, 1H), 7.12 (dd, J = 8.4, 6.8 Hz, 2H), 7.09 (d, J = 18.4 Hz, 1H), 7.05 (dd, J = 8.4, 1.2 Hz, 2H), 6.53 (d, J = 18.4 Hz, 1H), 6.35 (dd, J = 8.0, 1.2 Hz, 2H),5.83 (br s, 2H), 5.34 (s, 2H). ¹³C NMR (125 MHz, CDCl₃) δ 165.1, 140.0, 135.9, 134.7, 132.5, 132.4, 129.6, 129.5, 127.2, 127.1, 123.2, 119.8, 117.9, 105.8, 65.8. (The boron-bound carbon was not detected due to quadrupolar relaxation of boron). ¹¹B NMR (160 MHz, CDCl₃) δ 27.6. IR (Microscope, cm^-1) 3404, 3388, 3061, 1727, 1717, 1630, 1610, 1512. HRMS (EI) for C₂₀H₁₆BBrN₂O₄: calcd. 408. 0468; found 408.0477. M. P. 184–185°C.