[H-].[Na+].[F:3][C:4]1[CH:5]=[C:6]([CH:16]=[CH:17][CH:18]=1)[CH2:7]P(=O)(OCC)OCC.O=[C:20]1[CH2:25][CH2:24][N:23]([C:26]([O:28][CH2:29][C:30]2[CH:35]=[CH:34][CH:33]=[CH:32][CH:31]=2)=[O:27])[CH2:22][CH2:21]1>C1COCC1>[F:3][C:4]1[CH:5]=[C:6]([CH:16]=[CH:17][CH:18]=1)[CH:7]=[C:20]1[CH2:25][CH2:24][N:23]([C:26]([O:28][CH2:29][C:30]2[CH:31]=[CH:32][CH:33]=[CH:34][CH:35]=2)=[O:27])[CH2:22][CH2:21]1Sodium hydride (0.245 g) was added portionwise to a solution of diethyl (3-fluorobenzyl)phosphonate (Intermediate 182, 1 g) in THF (40 mL) at 0° C. The mixture was stirred for 30 minutes then benzyl 4-oxopiperidine-1-carboxylate (0.947 g) was added at 0° C. The mixture was allowed to warm to room temperature and stirred for 21.5 hours. The mixture was partitioned between water and ethyl acetate and the organic layer was washed with brine, dried (Na2SO4) and filtered. The filtrate was evaporated to dryness and the residue was purified by chromatography on silica eluting with a mixture of ethyl acetate and cyclohexane with a gradient of 0-25% to give benzyl 4-(3-fluorobenzylidene)piperidine-1-carboxylate (1.05 g)
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