Phosphorus tribromide → 3,5-Dimethoxybenzyl Bromide

Participants

Reaction Steps

(Snyder et al., Angewandte Chemie International Edition 2007, 46, 8186-8191.) To a stirred solution of 5 (17.5 g, 104 mmol, 1 equiv) in CH2Cl2 (500 mL) at 0° C. was added PBr3 (12.1 mL, 125 mmol, 1.2 equiv) dropwise. The reaction mixture was slowly allowed to warm to room temperature and stir for 3 h. The crude mixture was quenched with a saturated solution of aqueous. NaHCO3 and allowed to stir at room temperature for 1 h. The organic layer was separated and the aqueous layer was extracted with Et2O. The organic layers were combined, dried (MgSO4), filtered, and concentrated under reduced pressure to give 22.2 g (92% yield) of 6 as a white solid: Mp 70-72° C.; Rf 0.75 (EtOAc/hexanes, 1:2); IR (CDCl3) 2999, 2954, 1596, 1458, 1428, 1345, 1323, 1297, 1204, 1152, 1062, 930 cm−1; 1H NMR (400 MHz, CDCl3) δ 6.54 (d, 2 H, J=2.0 Hz), 6.39 (d, 1H, J=2.4 Hz), 4.42 (s, 2 H), 3.79 (s, 6 H); 13C NMR (150 MHz, CDCl3) δ 160.9, 139.7, 106.9, 100.6, 55.4, 33.6. Characterization matches that reported by Snyder et al. (Angewandte Chemie International Edition 2007, 46, 8186-8191.)

Provenance & Evidence