Hydrochloric Acid → (+)-4-chloro-2-methyl-9-trifluoromethyl-9H-fluoren-9-ol

Participants

Reaction Conditions

Reaction Steps

To a mixture of dimethylformamide (90 ml) and an optically active form (30 g) of (4-chloro-2-methyl-9-trifluoromethyl-9H-fluoren-9-yloxy)-acetic acid was added triethylamine (14.1 ml), and the mixture was stirred at 0° C. A solution of diphenylphosphoryl azide (20.0 ml) in dimethylformamide (60 ml) was added dropwise over 20 min, and the mixture was further stirred at 0° C. for 2 hr. To the reaction mixture was added t-butyl alcohol (75 ml), and the mixture was stirred at 100° C. for 1 hr. The reaction mixture was ice-cooled, 2N hydrochloric acid (300 ml) was added and the mixture was stirred at room temperature overnight. To this mixture was added water (100 ml) and the mixture was placed in a separatory funnel. The aqueous layer was extracted twice with toluene (300 ml, 200 ml). The combined organic layer was successively washed twice with water (200 ml), twice with 1N aqueous sodium hydroxide solution (150 ml) and once with saturated brine (150 ml), and dried over anhydrous sodium sulfate. Thereto was added silica gel (6 g) and the mixture was stirred at room temperature. The insoluble material was filtered off, and washed with toluene (500 ml). The filtrate was concentrated under reduced pressure to give the title compound (28.58 g).

Provenance & Evidence