Benzaldehyde → (R)(-)-2-Benzylamino-1-butanol

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Reaction Steps

Sodium triacetoxyborohydride (4.63 g) was added portionwisely to a mixture of (R)-(-)-2-amino-1-butanol (1.5 g) and benzaldehyde (1.79 g) in dichloromethane (50 ml) at 0° C. and the whole was stirred at room temperature overnight. The mixture was washed with sodium carbonate solution and brine, dried over sodium sulfate, and evaporated in vacuo to give (R)-2-benzylamino-1-butanol (2.69 g) [IR (Neat): 3292, 1460, 1350, 1136, 1061 cm−1]. A solution of chloroacetyl chloride (2.1 g) in tetrahydrofuran (4 ml) was added to a mixture of the obtained oil (2.69 g) and potassium carbonate (4.6 g) in a mixture of acetone (20 ml) and water (20 ml) at 0° C. After 1 hour of stirring, the solvent was replaced with ethyl acetate. The organic layer was separated, washed with brine, dried over sodium sulfate, and evaporated in vacuo. The residue was purified by column chromatography on silica gel to give N-benzyl-N-[(2R)-2-(1-hydroxybutyl)]-2-chloroacet amide (2.73 g) [IR (Neat): 3430, 1640, 1450, 1420, 1355, 1045 cm−1, MASS (APCI): 256 (M+H)+, 220] as an oil. Potassium tert-butoxide (1.22 g) was added to a solution of the above obtained oil (2.7 g) in tert-butanol (20 ml) portionwisely at room temperature and the whole was stirred overnight. The mixture was evaporated in vacuo, and ethyl acetate and water were added to the residue. The organic layer was separated, washed with brine, dried over sodium sulfate, and evaporated in vacuo to give (5R)-4-benzyl-5ethyl-3-morpholinone (2.33 g) as an oil.

Provenance & Evidence