反应详情

A solution of (±) 2-phenylpropionic acid (10.0 g, 0.66 mmol) and DMF (0.3 ml) in DCM (150 ml) was treated dropwise with oxalyl chloride (6.4 ml, 0.72 mmol). After 1 h the reaction mixture was concentrated in vacuo, the residual slurry diluted with Et2O (200 ml) and the resulting precipitate removed by filtration. The filtrate was treated with ethoxyacetylene (40% w/w solution in hexanes, 18 ml) followed dropwise with triethylamine (25 ml, 0.19 mol) and the reaction stirred for 7 d at rt. Filtration and concentration of the filtrate in vacuo followed by chromatography (SiO2, 5:1 EtOAc:hexanes) gave the title compound as a pale yellow oil (6.1 g, 45%). δH (CDCl3, 300K) 7.45-7.24 (5H, m), 5.01 (1H, s), 4.31 (2H, J 7.1 Hz), 1.67 (3H, s), 1.51 (3H, t, J 7.1 Hz); m/z (ES+, 70V) 202.9 (MH+).

1. concentrationAfter 1 h the reaction mixture was concentrated in vacuo
2. additionthe residual slurry diluted with Et2O (200 ml)
3. customthe resulting precipitate removed by filtration
4. additionThe filtrate was treated with ethoxyacetylene (40% w/w solution in hexanes, 18 ml)
5. filtrationFiltration and concentration of the filtrate in vacuo