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(2,3-Dihydrobenzo[1,4]dioxin-6-yl)-(3-ethoxy-4-methoxyphenyl)methanone (0.83 g, 2.64 mmol), cyanomethylphosphonic acid diethyl ester (0.83 ml, 5.28 mmol) in anhydrous THF (20 ml), and lithium bis(trimethylsilyl)amide (1.0 M solution in THF, 5.28 ml, 5.28 mmol) were treated in the same manner as described above for the synthesis of 3-(2,3-dihydrobenzo[1,4]dioxin-6-yl)-3-(3,5-dimethoxyphenyl)acrylonitrile. The crude material was purified via flash column chromatography (10% EtOAc in hexane gradient to 40% EtOAc in hexane in about 40 min.) to give a foam, which was lyophilized to give 3-(2,3-Dihydro-benzo[1,4]dioxin-6-yl)-3-(3-ethoxy-4-methoxy-phenyl)-acrylonitrile as a waxy oil (0.70 g, 78%): 1HNMR (DMSO-d6) 7.09-6.73 (m, 6H, Ar), 6.12 (s, 0.5H, double bond proton of one isomer), 6.07 (s, 0.5H, double bond proton of the other isomer), 4.33-4.25 (m, 4H, CH2CH2 for the two isomers), 4.05-3.97 (m, 2H, CH2CH3), 3.83 (s, 1.5H, OCH3 of one isomer), 3.79 (s, 1.5H, OCH3 of the other isomer), 1.31 (t, J=6 Hz, 3H, CH2CH3); 13C NMR (DMSO-d6) 161.0, 160.8, 151.0, 150.1, 147.8, 147.4, 145.5, 144.7, 143.2, 143.0, 131.3, 130.5, 130.1, 129.2, 122.6, 122.3, 120.0, 118.8, 118.7, 118.0, 117.1, 117.1, 117.0, 113.7, 112.1, 111.5, 111.3, 93.0, 92.9, 64.3, 64.2, 64.0, 64.0, 63.8, 55.5, 55.5, 14.6, 14.6. Anal. Calcd. For C20H19NO4 (+0.45H2O): C, 70.08; H, 5.76; N, 4.09. Found: C, 69.91; H, 5.54; N, 4.13.

1. customThe crude material was purified via flash column chromatography (10% EtOAc in hexane gradient to 40% EtOAc in hexane in about 40 min.)
2. customto give a foam, which