Methanol → (1R)-2-bromo-1-phenylethanol

(R)-2-amino-2-cyclohexyl-1,1-diphenylethanol (59 mg, 0.2 mmol), dry tetrahydrofuran (2 mL) and borane dimethylsulfide complex (100 μL, 1.0 mmol) were added to a dry flask under an atmosphere of nitrogen. The reaction mixture was stirred at room temperature for 1.5 hr to form (R)-4-cyclohexyl-5,5-diphenyl-1,3,2-oxazaborolidine. A solution of bromoacetophenone (199 mg, 1.0 mmol) in dry tetrahydrofuran (4 mL) was added to the borane/(R)-4-cyclohexyl-5,5-diphenyl-1,3,2-oxazaborolidine complex at the rate of 9 mL/hr by means of a syringe pump. The resulting mixture was stirred at room temperature for an additional 1.5 hr. Methanol was added to quench the reaction and then the solvent was removed by evaporation. The resulting residue was chromatographed on silica gel (hexane/ethyl acetate, 25:1) and combination of the like fractions, followed by removal of the solvent gave (R)-2-bromo-1-phenylethanol (170 mg, 97.9% ee). The enantiomeric excess was measured by HPLC (Chiralcel OD-H column, mobile phase, hexane/2-propanol 9:1, flow rate=0.7 mL/min).

1. customto quench
2. customthe reaction
3. customthe solvent was removed by evaporation
4. customThe resulting residue was chromatographed on silica gel (hexane/ethyl acetate, 25:1) and combination of the like fractions
5. customfollowed by removal of the solvent

ORDレコード

ord-53cf697152c442acad1c810dea9d64ae

出典データセット

uspto-grants-2003_01

DOI

10.6084/m9.figshare.5104873.v1

特許番号

US06509472B2