Phenylacetaldehyde → (S)-3-Phenylethylamino-2-oxo-1-piperidineacetic acid, benzyl ester hydrochloride

Participants

Reaction Steps

To a mixture of 41 (1.50 g, 5.02 mmol) and phenylacetaldehyde (0.724 g, 6.03 mmol) in 35 mL of 1, 2-dichloroethane was added triethylamine (2.03 g, 21.1 mmol, 2.80 mL). After stirring at ambient temperature for 10 min, sodium triacetoxyborohydride (1.49 g, 7.03 mmol) was added rapidly over a 5 min period. The reaction mixture was stirred at room temperature for 15 hrs and quenched with 30 mL of water. The mixture was diluted with 50 mL of CH2Cl2 and the organic phase was separated, washed with 30 mL portions of saturated NaHCO3, water, brine, dried over MgSO4, filtered, and evaporated. The residue was purified by flash chromatography on silica gel eluting with CH2C12, ethanol: 95, 5 to afford 1.21 g (66% yield) of product 42 as a pale yellow oil; TLC (silica gel; CH2Cl2, ethanol: 9, 1): Rf=0.4

Provenance & Evidence