[F-].C([N+](CCCC)(CCCC)CCCC)CCC.[CH2:19]([O:21][C:22](=[O:31])[CH:23]=[C:24]1[CH2:28][CH2:27][C:26]([CH3:30])([CH3:29])[CH2:25]1)[CH3:20].[N+:32]([CH3:35])([O-:34])=[O:33]>C1COCC1.C(OCC)(=O)C>[CH2:19]([O:21][C:22](=[O:31])[CH2:23][C:24]1([CH2:35][N+:32]([O-:34])=[O:33])[CH2:28][CH2:27][C:26]([CH3:30])([CH3:29])[CH2:25]1)[CH3:20]Tetrabutylammonium fluoride (5.75 mL of a 1 M solution in THF, 5.75 mmol) was added to a solution of the ester 2 (697 mg, 3.83 mmol) and nitromethane (467 mg, 7.66 mmol) in THF (20 mL) and the mixture heated to 70° C. After 19 hours, nitromethane (233 mg, 1.9 mmol) and tetrabutylammonium fluoride (1.9 mL of a 1 M solution in TBF, 1.9 mmol) were added and reflux continued for 7 hours, whereupon the solution was cooled to room temperature, diluted with ethyl acetate (40 mL), and washed with 2N HCl (20 mL) then brine (20 mL). The organic phase was dried (MgSO4) and concentrated. The crude product was flash chromatographed (9:1 hexane/ethyl acetate) to give the nitro ester 3 (380 mg, 41%) as an oil.
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