GENERAL STEPS: Phosphorus tribromide (0.51 mL, 5.4 mmol) was added slowly and dropwise to a stirred solution of ethyl 2-hydroxymethacrylate (2 g, 15.4 mmol) in ether (15 mL) at 0 °C. The reaction mixture was stirred at 0 °C for 3 h and subsequently warmed to room temperature. The reaction was quenched by the addition of water (5 mL) and the product was extracted with hexane (3 x 10 mL). The organic layers were combined, washed with brine (2 × 10 mL), dried over anhydrous MgSO4, filtered and concentrated in vacuum to afford ethyl 2-bromomethacrylate (2.4 g, 12.3 mmol, 82% yield) as a colorless liquid, which could be used in the next reaction without further purification. The product was characterized as follows: colorless oil; 1H NMR (400 MHz, CDCl3) δ 1.30 (t, J = 7.2 Hz, 3H, H6), 4.16 (s, 2H, H4), 4.24 (q, J = 7.0 Hz, 2H, H5), 5.92 (s, 1H, H1'), 6.30 (s, 1H, H1); 13C NMR ( 101 MHz, CDCl3) δ 14.1 (CH3, C6), 29.3 (CH2, C4), 61.2 (CH2, C5), 128.8 (CH2, C1), 137.6 (C, C2), 164.8 (C, C3); IR (νmax, cm-1) 1718 (C=O ester), 1628 (C=C alkene), 1182 (C-O ester), 523 (C-Br); HRMS-EI: m/z [M+H]+ calcd for C6H10BrO2: 192.9864, found: 192.6870.
