To a suspension of [2-benzyloxy-5-(5-methyl-7-nitroindan-4-yloxy)benzyl]triphenylphosphonium chloride (559 mg) in dimethylsulfoxide (20 mL) was added sodium hydride (60%, 49 mg) at room temperature, the mixture was stirred for 15 min. After adding tetrahydro-4H-pyran-4-one (0.15 mL), the reaction mixture was stirred at room temperature for 6 hours. After adding dropwise diluted hydrochloric acid to make the mixture acidify fully, the reaction mixture was extracted with ethyl acetate. The organic layer was washed with brine, and dried over anhydrous magnesium sulfate. The solvent was removed-under reduced pressure. The residue was purified by column chromatography on silica gel (eluent: hexane/ethyl acetate) to give the title compound (230 mg).
