p-Toluenesulfonic acid → HCID 9794426, compound

Participants

Reaction Steps

To a solution of (R)-(+)-binaphthol (7.9 mg, 0.0275 mmol) in CH2Cl2 (0.5 mL) was added a solution of Ti(OiPr)4 (3.8 uL, 3.6 mg, 0.0125 mmol) in CH2Cl2 (0.5 mL). Upon stirring at room temperature for 5-10 h, the reaction mixture was concentrated and dried using a vacuum pump (ca. 0.5 h). The catalyst was then dissolved in Et2O (1 mL) and cooled in an ice bath. To this solution was added a solution of racemic 1-benzoyloxy-1,2-epoxycyclohexane (0.109 g, 0.5 mmol) in Et2O (1 mL). After stirring at 0° C. for 1 h, the reaction mixture was quenched with saturated NaHCO3 solution (4 mL) and poured into a mixture of ether (20 mL) and saturated NaHCO3 solution (10 mL). The organic layer was washed with water and brine, dried (Na2SO4), and rapidly filtered through a plug of silica gel (ca. 10 g) (pre-treated with 5% Et3N in hexane and washed thoroughly with hexane to remove Et3N before use). The silica gel was further washed with Et2O (10 mL). The combined ether solutions were concentrated to give a residue. Upon drying under vacuum for 1 h, the mixture was dissolved in CH2Cl2 (4 mL) followed by addition of anhydrous p-TsOH (8.6 mg, 0.05 mmol). After stirring at room temperature for 20 min, the mixture was rapidly filtered through a plug of silica gel (ca. 10 g) (without Et3N treatment) followed by washing with ether (2×10 mL). The combined solutions were concentrated to give (R)-2-benzoyloxycyclohexanone as a white solid (0.0845 g, 78% yield, 93% ee).

Provenance & Evidence