反应详情

A solution of ethyl 2-cyano-3-methylcrotonate (10.8 g, 0.07 mol) in THF (100 mL) was added dropwise to a stirred ethereal solution of 3-methoxybenzylmagnesium chloride (prepared by adding a solution of 3-methoxybenzyl chloride (9.3 mL, 0.064 mol) in ether (48 mL) to a slurry of Mg (1.7 g, 0.07 mol) in ether (20 mL)). After addition the mixture was stirred at room temperature for a further 2 h then NH4Cl (sat., 50 mL) was added. The solution was partitioned between EtOAc (200 mL) and water (200 mL) and the organic layer separated and dried (MgSO4). The solvent was evaporated and the residue chromatographed on silica gel, eluting with petrol:EtOAc (5:1). The title compound (9.0 g, 51%) was isolated as a colourless oil. 1H NMR (360 MHz, CDCl3) δ 1.10 (3H, s), 1.20 (3H, s), 1.33 (3H, t, J=7.1 Hz), 2.74 (1H, d, J=13.5 Hz), 2.78 (1H, d, J=13.5 Hz), 3.33 (1H, s), 3.81 (3H, s), 4.26 (2H, q, J=7.1 Hz), 6.72-6.82 (3H, m), 7.22 (1H, t, J=7.8 Hz). MS (ES+) 276 (M+1).

1. customprepared
2. additionAfter addition the mixture
3. customThe solution was partitioned between EtOAc (200 mL) and water (200 mL)
4. customthe organic layer separated
5. dry with materialdried (MgSO4)
6. customThe solvent was evaporated
7. customthe residue chromatographed on silica gel
8. washeluting with petrol:EtOAc (5:1)