Dimethyl Sulfoxide → (R)-3-(dibenzylamino)cyclohexanone

Participants

Reaction Conditions

Reaction Steps

Oxalyl chloride (2.70 mL, 30.9 mmol) was dissolved in dry DCM (150 mL) and cooled to −78° C. DMSO (4.78 mL, 67.3 mmol) in dry DCM (20 mL) was added dropwise to the reaction mixture and the reaction was stirred for 15 min at −78° C. Next, (1S,3R)-3-(dibenzylamino)cyclohexanol (8.287 g, 28.1 mmol) in dry DCM (100 mL) was added drop wise using an addition funnel and the reaction mixture was stirred at −78° C. for 15 min. TEA (19.55 mL, 140 mmol) was then added and the reaction was stirred at −78° C. for 1 h. The dry-ice bath was removed and the reaction mixture was allowed to warm to room temperature and stirred overnight. The reaction mixture was washed with brine (100 mL), the organic layer was separated, dried over magnesium sulfate and concentrated. Upon slow addition of diethyl ether to the residue the impurities precipitated, and were separated by filtration. Addition of diethyl ether to the filtrate yielded (R)-3-(dibenzylamino)cyclohexanone (6.05 g, 74%) as a white solid which was collected by filtration and dried. 1H NMR (400 MHz, DMSO-d6) δ ppm 7.26-7.39 (m, 8H), 7.17-725 (m, 2H), 3.56-3.70 (m, 4H), 2.71-2.81 (m, 1H), 2.60-2.69 (m, 1H), 2.25-2.42 (m, 2H), 2.04-2.11 (m, 1H), 1.88-1.99 (m, 2H), 1.69-1.82 (m, 1H), 1.18-1.33 (m, 1H); MS (ESI) m/z 294.4 [M+1]+.

Provenance & Evidence