反应详情

To a stirred suspension of sodium hydride [588 mg (60% oil dispersion), 15 mmol), which had been previously washed with pentane (3×), in THF (30 mL) in a 0° C. ice bath is added methyl triphenylphosphonium bromide (4.6 g, 13 mmol). The suspension is allowed to warm to rt and stir for 30 min. A solution of ethyl 4-(allyloxy)-3-formylbenzoate (2.3 g, 9.8 mmol) in THF (10 mL) is added via canula. The mixture is stirred at rt 2 h. The mixture is diluted with EtOAc and washed with brine. The organic layer is dried of MgSO4, filtered and concentrated in vacuo to a yellow residue. The crude product is purified by flash chromatography on SiO2. Elution with hexanes-EtOAc (95:5) gives 1.8 g (79%) of ethyl 4-(allyloxy)-3-vinylbenzoate as a clear oil: 1H NMR (400 MHz, CDCl3) δ 8.2, 7.9, 7.1, 6.9, 6.1, 5.9, 5.5, 5.3, 4.7, 4.4, 1.4.

1. washhad been previously washed with pentane (3×), in THF (30 mL) in a 0° C. ice bath
2. stirringThe mixture is stirred at rt 2 h
3. washwashed with brine
4. dry with materialThe organic layer is dried of MgSO4
5. filtrationfiltered
6. concentrationconcentrated in vacuo to a yellow residue
7. customThe crude product is purified by flash chromatography on SiO2
8. washElution with hexanes-EtOAc (95:5)