N(C(OCC)=O)=NC(OCC)=O.OC1C=C([O:20][S:21]([C:24]2[CH:29]=[CH:28][CH:27]=[CH:26][C:25]=2[Cl:30])(=[O:23])=[O:22])C=CC=1.C(C1C=C(C=CC=1)CO)#N.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>O1CCCC1>[Cl:30][C:25]1[CH:26]=[CH:27][CH:28]=[CH:29][C:24]=1[S:21]([OH:23])(=[O:22])=[O:20]Diethyl azodicarboxylate (174 mg, 1.0 mmol) was added to a solution of 2-chlorobenzenesulfonic acid 3-hydroxyphenyl ester (285 mg, 1.0 mmol), as prepared in the preceding step, 3-cyanobenzyl alcohol (133 mg, 1.0 mmol)(Yoon et al., J. Org. Chem. 38:2786-2792 (1973)), and triphenylphosphine (263 mg, 1.0 mmol) in tetrahydrofuran (10 mL) at 0° C. The mixture was stirred at 0° C. for 2 hours and at room temperature for 3 hours. The reaction mixture was quenched with water (30 mL) and extracted with ethyl acetate (3×30 mL). The organic phase was washed with saturated NaHCO3 (2×30 mL), brine (2×30 mL) and dried over Na2SO4. The solvent was removed in vacuo the residue was purified by flash column chromatography (2:1 ethyl acetate:hexane) to give the title compound as a pale yellow oil (375 mg, 93%). 1H-NMR (300 MHz, CDCl3) δ 5.02 (s, 2 H), 6.78 (m, 2 H), 6.85 (dd, 1H, J=4.2, 1.3 Hz), 7.20 (t, 1H, J=8.2 Hz), 7.38 (t, 1H, J=5.8 Hz), 7.51 (t, 1H, J=7.7 Hz), 7.59-7.68 (m, 5 H) and 7.93 (dd, 1 H, J=4.0, 0.7 Hz).
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