[CH3:1][O:2][C:3]1[CH:4]=[C:5]([OH:12])[CH:6]=[CH:7][C:8]=1[N+:9]([O-:11])=[O:10].C([O-])([O-])=O.[Cs+].[Cs+].[O:19]1[CH2:24][CH2:23][CH:22](OS(C)(=O)=O)[CH2:21][CH2:20]1>CN(C=O)C.O>[CH3:1][O:2][C:3]1[CH:4]=[C:5]([CH:6]=[CH:7][C:8]=1[N+:9]([O-:11])=[O:10])[O:12][CH:22]1[CH2:23][CH2:24][O:19][CH2:20][CH2:21]1Step B To a solution of 3-methoxy-4-nitrophenol (0.5 g, 3 mmol) prepared in Example 132 Step A in anhydrous DMF (13 mL) were added Cs2CO3 (2.9 g, 8.9 mmol) and methanesulfonic acid tetrahydropyran-4-yl ester (0.64 g, 3.6 mmol) sequentially. The reaction mixture was heated at 120° C. for 3 h. The mixture was cooled to room temperature, and diluted with water. The mixture was extracted with ethyl acetate three times. The combined organic extract was washed with water, brine, dried over MgSO4, and concentrated. The residue was purified by chromatography (40-60% EtOAc in hexanes) to give 4-(3-methoxy-4-nitrophenoxy)tetrahydro-2H-pyran as a yellow oil (0.4 g, 53%).
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