Reaction Steps
To a solution of cyanomethylphosphonic acid diethyl ester (2.4 mL, 15.0 mmol) in anhydrous THF (20 mL) was added lithium bis(trimethylsilyl)amide (1.0 M solution in THF, 15.0 mL, 15.0 mmol) at 0° C. and stirred for 30 min at room temperature followed by addition of (2,3-dihydro-benzo[1,4]dioxin-6-yl)-(4-methoxy-phenyl)-methanone (2.02 g crude, 7.5 mmol) in THF (15 mL) and refluxed for 30 min. The reaction mixture was poured into water (50 if L), extracted with CH2Cl2 (2×50 mL). The combined organic phases were washed with brine (50 mL), dried over MgSO4, and purified via flash column chromatography (EtOAc, Hexane) to give 3-(2,3-dihydro-benzo[1,4]dioxin-6-yl)-3-(4-methoxy-phenyl)-acrylonitrile as a yellow solid (1.44 g, 66% yield): mp, 112-114° C.; 1H NMR (DMSO-d6) δ 3.79 and 3.83 (2s, 3H, OCH3), 4.25-4.33 (m, 4H, CH2CH2), 6.07 and 6.08 (2s, 1H, CH), 6.77-7.32 (m, 7H, Ar); 13C NMR (DMSO-d6) δ 55.2, 55.3, 64.0, 64.0, 64.2, 64.3, 92.7, 93.0, 113.9, 114.1, 117.0, 117.2, 118.0, 118.6, 118.7, 121.9, 122.5, 129.1, 130.0, 130.1, 130.4, 130.8, 131.4, 143.1, 143.2, 144.7, 145.5, 160.3, 160.7, 160.8, 161.1. Anal. Calcd for C18H15NO3+0.1H2O: C, 73.26; H, 5.19; N, 4.75. Found: C, 72.96; H, 5.22; N, 4.67.
