C[C:2]([O-:5])(C)C.[K+].[CH:7]1C=CC(P(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.[CH3:26][O:27][C:28](=[O:40])[C:29]1[C:34]([N+:35]([O-:37])=[O:36])=[CH:33][CH:32]=[CH:31][C:30]=1[CH:38]=O>C1COCC1>[CH3:26][O:27][C:28](=[O:40])[C:29]1[C:34]([N+:35]([O-:37])=[O:36])=[CH:33][CH:32]=[CH:31][C:30]=1[CH:38]=[CH:7][O:5][CH3:2]t-BuOK (5.5 g, 58 mmol, 2 eq) was added portion-wise to a stirred suspension of Ph3P+CH2OmeCl− (21.7 g, 63 mmol, 2.2 eq) in THF (100 mL) under N2 in an ice-bath. After stirring the red solution at RT for 30 min, 2-formyl-6-nitro-benzoic acid methyl ester (Example 1, Step C, 5.1 g, 29 mmol, 1 eq) in THF (15 mL) was added. The reaction was stirred at RT for 1 h, quenched with saturated NH4Cl and extracted with EtOAc. The organic layer was washed with H2O (2×), dried (MgSO4) and concentrated in vacuo to give a dark oil. Purification by silica flash chromatography (0-20% EtOAc:hexane) gave the desired compound as a yellow oil (a mixture of ca. 1.7:1 E/Z isomers).
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