[H-].[Na+].C(OP([CH2:11][C:12]([O:14][CH2:15][CH3:16])=[O:13])(OCC)=O)C.[C:17]([C:21]1[CH:26]=[CH:25][C:24]([CH:27]=O)=[CH:23][C:22]=1[N+:29]([O-:31])=[O:30])([CH3:20])([CH3:19])[CH3:18]>CCCCCC.CN(C)C=O.C(OCC)C>[C:17]([C:21]1[CH:26]=[CH:25][C:24](/[CH:27]=[CH:11]/[C:12]([O:14][CH2:15][CH3:16])=[O:13])=[CH:23][C:22]=1[N+:29]([O-:31])=[O:30])([CH3:20])([CH3:18])[CH3:19]
8.0 g (0.18 mol) of sodium hydride (as a 55% w/w dispersion in mineral oil) was washed twice with hexane and suspended in 250 ml of dimethylformamide. A solution of 31 ml (0.16 mol) of ethyl diethylphosphonoacetate in 50 ml of dimethylformamide was then added, with ice-cooling, to the suspension, and the resulting mixture was stirred at room temperature for 40 minutes. At the end of this time, the mixture was ice-cooled and a solution of 27 g (0.13 mol) of 2-t-butyl-5-formyl-1-nitrobenzene [prepared as described in step (i) above] in 50 ml of dimethylformamide was added thereto over a period of 30 minutes, after which the mixture was stirred for 1 hour. The reaction mixture was then diluted with diethyl ether, and the diluted solution was washed with a 10% w/w aqueous solution of hydrochloric acid and with water, in that order, after which it was dried over anhydrous sodium sulfate. The solvent was removed by distillation under reduced pressure, and the resulting residue was purified by column chromatography through silica gel, using a 1:6 by volume mixture of ethyl acetate and hexane as the eluent, to give 20.6 g of the title compound as crystals, melting at 77-78° C. (from ethyl acetate-hexane).
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