(3aS)-1-methyl-3,3-diphenyl-hexahydropyrrolo(1,2-c)(1,3,2)oxazaborole → (S)-2-bromo-1-pyridin-3-yl-ethanol

Participants

Reaction Steps

(S)-2-Methyl-CBS-oxazaborolidine (1M in toluene, 189 μL, 0.18 mmol) and borane-methyldisulfide complex (2M in toluene, 100 μL) in THF (11 mL) was allowed to stir at room temperature for 10 min. Then, the rest of BH3—S(CH3)2 (2M in toluene, 1.33 mL, 2.85 mmol) was added to the reaction solution followed by a suspension of 3-(bromoacetyl)pyridine hydrochloride (0.5 g, 1.78 mmol) in THF (11 mL). The heterogeneous reaction mixture was stirred at room temperature for 16 h. The reaction mixture was then cooled to 0° C. and quenched with MeOH (1.5 mL). After 5 min of stirring, the solvent was removed and the resulting residue was diluted with CH2Cl2. The solution was treated with saturated NaHCO3 and the organic phase was separated. The aqueous phase was re-extracted with CH2Cl2. The combined organic phase was dried over Na2SO4 and concentrated. The resulting residue was purified by silica gel prep TLC using 95:5 CH2Cl2:MeOH as an eluent to afford 0.24 g of (S)-2-bromo-1-pyridin-3-yl-ethanol as a colorless oil (66%).

Provenance & Evidence