0.28 g of lithium chloride, 0.85 g of diisopropylethylamine and 2.13 g of 4-formyl-l-t-butoxycarbonylpiperidine were added to 2.0 g of diethyl (4-nitrobenzoylmethyl)phosphonate dissolved in 20 ml of acetonitrile, and the mixture was stirred at room temperature for about 3 days. Then, water was added to the reaction mixture, and the mixture was extracted with toluene. The extract was dried over anhydrous sodium sulfate and condensed. The obtained residue was applied to silica gel column chromatography to obtain 1.76 g of the title compound as pale yellow crystal.
