Methanol → 2,3-Dihydro-5-(trifluoromethoxy)-1H-inden-1-ol

Temperatur

5 °C

(2S)-1-(1,3,2-Dioxaborolan-2-yloxy)-3-methyl-1,1-diphenylbutan-2-amine (33 mg, 0.1 mmol) obtained in a similar manner to the method of European Journal of Organic Chemistry, 1999, p. 1775 (Eur. J. Org. Chem. 1999, 1775) was suspended in tetrahydrofuran (5 mL), and then thereto was added borane dimethylsulfide complex (10 mol/L, 0.1 mL, 1 mmol) at room temperature. The mixture was stirred at the same temperature for 20 minutes, and then thereto was added in divided portions 5-trifluoromethoxyindan-1-one (0.217 g, 1 mmol) obtained in a similar manner to the method of U.S. Pat. No. 6,159,996 over 1 hour, and the mixture was stirred at room temperature overnight. The mixture was cooled to 5° C., and then thereto was added methanol (2 mL). The mixture was stirred at the same temperature for 1 hour, and then the reaction solution was concentrated, and then thereto was added chloroform. The chloroform solution was poured into saturated aqueous ammonium chloride solution, and extracted with chloroform three times, and the organic layer was washed with saturated brine. The resultant was dried over magnesium sulfate, and then concentrated. To the resulting residue were added diethyl ether and hexane, and the generated white solid was filtered off. The filtrate was concentrated to give a crude 5-(trifluoromethoxy)indan-1-ol (62.5 mg). The resultant was used in the next step without further purification.