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

(R)-2-amino-2-cyclohexyl-1,1-diphenylethanol (59 mg, 0.2 mmol), dry tetrahydrofuran (2 mL) and trimethylboroxine (27.2 μL, 0.24 mmol) were added to a dry flask under an atmosphere of nitrogen, then stirred for 1.5 hr to form a solution of (R)-4-cyclohexyl-5,5-diphenyl-2-methoxy-1,3,2-oxazaborolidine. Borane dimethylsulfide complex (100 μL, 1.0 mmol) was added and the reaction stirred for 30 minutes. Then, a solution of bromoacetophenone (199 mg, 1.0 mmol) in dry tetrahydrofuran (4 mL) was added at the rate of 9 mL/hr by means of a syringe pump. After 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 20:1) and combination of the like fractions, followed by removal of the solvent gave (R)-2-bromo-1-phenylethanol (130 mg, 98.7% 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. additionBorane dimethylsulfide complex (100 μL, 1.0 mmol) was added
2. waitAfter 1.5 hr
3. customto quench
4. customthe reaction
5. customthe solvent was removed by evaporation
6. customThe resulting residue was chromatographed on silica gel (hexane/ethyl acetate 20:1) and combination of the like fractions
7. customfollowed by removal of the solvent

ORDレコード

ord-2069b0fc8bf6470f94589f0d34aa5872

出典データセット

uspto-grants-2003_01

DOI

10.6084/m9.figshare.5104873.v1

特許番号

US06509472B2