[H-].[Na+].[OH:3][C:4]1([CH2:17][CH:18]=[CH2:19])[CH2:9][CH2:8][N:7]([C:10]([O:12][C:13]([CH3:16])([CH3:15])[CH3:14])=[O:11])[CH2:6][CH2:5]1.[CH2:20](Br)[CH:21]=[CH2:22].O>CN(C)C=O>[CH2:17]([C:4]1([O:3][CH2:22][CH:21]=[CH2:20])[CH2:5][CH2:6][N:7]([C:10]([O:12][C:13]([CH3:14])([CH3:15])[CH3:16])=[O:11])[CH2:8][CH2:9]1)[CH:18]=[CH2:19]
Sodium hydride (60% dispersion in mineral oil, 12 g, 0.3 mol) was added slowly to a stirred, cooled (0° C.) solution of 1,1-dimethylethyl 4-hydroxy-4-(2-propenyl)-1-piperidinecarboxylate (Description 129, 23.1 g, 0.096 mol) in dimethylformamide (200 mL) and the mixture was stirred at 0° C. for 10 minutes. Allyl bromide (25.4 ml, 0.3 mol) was added and the mixture was stirred at 0° C. for 5 minutes, then at room temperature for 45 minutes. The mixture was cooled to 0° C. and water (200 mL) was added. The mixture was extracted with diethyl ether (2×200 mL) and the combined organic fractions were washed with water (4×200 mL) and brine (150 mL), dried (MgSO4) and the solvent was evaporated under reduced pressure. The residue was purified by flash column chromatography on silica gel, eluting with isohexane/EtOAc (9:1), to give the title compound (5.5 g, 20%). m/z (E) 226 (M+1-C4H8).
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