Sodium hydride → 1-(Benzyloxycarbonyl)-4-(3-oxo-3-phenylprop-1-enyl)piperidine

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Reaction Steps

Diethyl (2-oxo-2-phenylethyl)phosphonate (0.96 mL,1.1 g, 4.4 mmol) was added in one portion to a stirred suspension of sodium hydride (60% oil dispersion, 158 mg, 3.95 mmol) in THF (20 mL). After 15 min. at RT, the clear solution was cooled in an ice bath and 1-(benzyloxycarbonyl)-4-piperidinecarboxaldehyde (840 mg, 3.40 mmol) was added in THF (1.0 mL) with additional THF (2×1.0 mL) for rinsing. Stirring was continued for a total of 2 h, with slow warming to RT. The mixure was then partitioned between ether (120 ml) and 2.5 N NaOH (60 mL). The organic layer was washed with saturated aq. NaCl (60 mL), dried (Na2SO4), decanted, and evaporated. The crude product was purified by flash column chromatography on silica gel eluting with 85:15 v/v to 80:20 v/v hexanes/EtOAc to give 0-95 g of the title compound as a colorless syrup: 1H NMR (400 MHz) δ 7.82 (d, J=8, 21), 7.57 (t, J=8, 1H), 7.48 (t, J=8, 2H), 7.39-7.29 (m, 51), 6.99 (dd, J=15, 6, 1H), 6.87 (dd, J=15, 1, 1H), 5.15 (s, 2H), 2.97-2.82 (m, 2H), 2.50-2.39 (m, 1H), 1.89-1.77 (m, 2H), 1.54-1.39 (m, 2H); ESI-MS 367 (M+NH3+H).

Provenance & Evidence