1-Tetralone → 1,2,3,4-Tetrahydro-2-naphthalenol

Participants

Reaction Conditions

Reaction Steps

(1R, 2S)-2-tert-butyl-2-aminophenylethanol (1.0 g, 5.2 mmol), toluene (16 mL), and trimethylboroxine (0.50 mL) were combined at ambient temperature and stirred for 16 hr. Water, toluene and excess boroxine were distilled off until about 8 mL volume remained. The reaction was chased with toluene (3×10 mL), and the remainder of toluene removed under vacuum to afford to oxazaborolidine as a pale yellow oil (1.10 g, 98%). To a solution of α-tetralone (2.92 g, 19.7 mmol), THF (80 mL), and the oxazaborolidine derived from (1R, 2S)-2-tert-butyl-2-aminophenylethanol (228 mg, 1.2 mmol) under a nitrogen atmosphere was added borane methylsulfide complex (2M in THF, 7.0 mL, 14 mmol) over 75 min. After the addition was complete, the contents were stirred for an additional 15 min, cooled to 0° C., and quenched with methanol (27 mL). After stirring the quenched reaction for 18 hrs the solvents were removed under vacuum, the residual oil was dissolved in methylene chloride (50 mL), washed with pH 4 phosphate buffer (50 mL), water (50 mL), treated with magnesium sulfate, and the solvent was removed under vacuum to give the (R) tetralol as a colorless oil 3.1 g (90% ee).

Provenance & Evidence