[N+:1]([CH2:4][C:5]([O:7][CH2:8][CH3:9])=[O:6])([O-:3])=O.C1N2[CH2:16][CH2:17]N(CC2)C1.[CH2:18]([OH:20])C>>[OH:20][CH2:18][CH:16]1[O:3][N:1]=[C:4]([C:5]([O:7][CH2:8][CH3:9])=[O:6])[CH2:17]1To a mixture of allylic alcohol (0.650 mL; 9.35 mmol) and ethyl 2-nitroacetate (2.65 mL; 23.37 mmol) in ethanol (12 mL) in an Ace pressure tube was added 1,4-diazobicyclo[2.2.2]octane (DABCO, 0.189 g; 1.64 mmol). The tube was heated at 80° C. for 48 h. The mixture was evaporated. The flash chromatography on silica gel (eluent: 0 to 6% of methanol in dichloromethane) of the residue provided 1.51 g (93%) of ethyl 5-(hydroxymethyl)-4,5-dihydroisoxazole-3-carboxylate as an oil.
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