[N+:1]([C:4]1[CH:11]=[CH:10][C:7]([CH:8]=O)=[CH:6][CH:5]=1)([O-:3])=[O:2].[C:12]([CH:17]=P(C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)([O:14][CH2:15][CH3:16])=[O:13].C1(P(=O)(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>C(Cl)Cl>[CH2:15]([O:14][C:12](=[O:13])[CH:17]=[CH:8][C:7]1[CH:10]=[CH:11][C:4]([N+:1]([O-:3])=[O:2])=[CH:5][CH:6]=1)[CH3:16]A solution of 4-nitrobenzaldehyde (53, 10.00 g, 66.23 mmol) and (carbethoxymethylene)triphenylphosphorane (27.92 g, 72.85 mmol, 1.1 equiv) was refluxed in CH2Cl2 (74 mL) for 24 h. The solvent was removed at reduced pressure. The oily residue was chromatographed (silica, hexanes/diethyl ether, 1:1) to give a pale yellow solid, which was shown by 1H NMR and TLC analysis to contain triphenylphosphine oxide. This sample was further purified by short-path Kugelrohr distillation (0.05 mmHg, up to 180° C.) to yield a pale yellow solid (3.74 g, 26%, mixture of E and Z isomers): 1H NMR δ 1.33 (t, J=7.5 Hz, 3H), 4.27 (q, J=7.5 Hz, 2H), 6.54 (d, J=15.6 Hz, 1H), 7.62-7.71 (m, 3H), 8.17-8.24 (m, 2H); 13C NMR δ 14.48, 61.22, 122.81, 123.54, 124.38, 130.43, 132.24, 140.76, 141.82, 166.24.
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