Lithium tri-s-butylborohydride → (1R,2S,4S)-4-(dibenzylamino)-2-methylcyclohexanol (1S,2R,4R)-4-(dibenzylamino)-2-methylcyclohexanol

Participants

Reaction Conditions

Reaction Steps

To a solution of (2S,4S)-4-(dibenzylamino)-2-methylcyclohexanone/(2R,4R)-4-(dibenzylamino)-2-methylcyclohexanone (3.1 g, 10.08 mmol) in THF (55 mL) at −78° C. was added L-selectride (15.13 mL, 15.13 mmol) dropwise. After stirring for 5 min at −78° C. the mixture was allowed to warm up to 0° C. Stirring was continued for 18 hr as the reaction mixture was warmed from 0° C. to ambient temperature. The mixture was diluted carefully with 1N aq NaOH (15 mL) and stirred vigorously for 3 hr. The mixture was extracted with EtOAc (3ט100 mL). The combined organic layers were washed with brine (˜100 mL), dried over Na2SO4, filtered off and concentrated in vacuo. The resulting residue was purified by column chromatography [SiO2, 120 g, EtOAc/hexane=0/100 to 20/80 over-25 min; EtOAc/hexane=20/80 to 40/60 over 5 min] providing (1R,2S,4S)-4-(dibenzylamino)-2-methylcyclohexanol/(1S,2R,4R)-4-(dibenzylamino)-2-methylcyclohexanol as a colorless liquid. Yield: 2.83 g. LCMS (m/z): 310.3 [M+H]+; Retention time=0.66 min.

Provenance & Evidence