Tetrahydrofuran → HCID 59033424, compound
Reaction equation
[NH2:1][C@H:2]([CH:25]1[CH2:30][CH2:29][CH2:28][CH2:27][CH2:26]1)[C:3]([C:15]1[CH:24]=[CH:23][C:22]2[C:17](=[CH:18][CH:19]=[CH:20][CH:21]=2)[CH:16]=1)([C:5]1[CH:14]=[CH:13][C:12]2[C:7](=[CH:8][CH:9]=[CH:10][CH:11]=2)[CH:6]=1)[OH:4].C[B:32]1[O:37]B(C)OB(C)O1.O1CCC[CH2:41]1>>[CH:25]1([C@@H:2]2[C:3]([C:15]3[CH:24]=[CH:23][C:22]4[C:17](=[CH:18][CH:19]=[CH:20][CH:21]=4)[CH:16]=3)([C:5]3[CH:14]=[CH:13][C:12]4[C:7](=[CH:8][CH:9]=[CH:10][CH:11]=4)[CH:6]=3)[O:4][B:32]([O:37][CH3:41])[NH:1]2)[CH2:30][CH2:29][CH2:28][CH2:27][CH2:26]1Participants
Procedure
(R)-2-amino-2-cyclohexyl-1,1-bis(2-naphthyl)ethanol (79.1 mg, 0.2 mmol) and 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 hour to form a solution of (R)-4-cyclohexyl-5,5-bis(2-naphthyl)-2-methoxy-1,3,2-oxazaborolidine. Borane dimethylsulfide complex (100 μL, 1.0 mmol) was added and the reaction was stirred for 30 minutes. Then, a solution of bromoacetophenone (199 mg, 1.0 mmol) in dry tetrahydrofuran (3 mL) was added at the rate of 9 mL/hr by means of a syringe pump. After 2 hours, methanol was added to quench the reaction, followed by 0.5 N ethanolic HCl (0.4 mL). The solvent was removed by evaporation under vacuum and the resulting residue was chromatographed on silica gel (hexane/ethyl acetate 25:2). Combination of the like fractions, followed by removal of the solvent gave (R)-2-bromo-1-phenylethanol (130 mg, 93% yield, 98.3% 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).
Sources & evidence
- ORD record
- ord-04ebdfb77d4a4c229162988f68b4e4c3
- Source dataset
- uspto-grants-2003_01
- Patent number
- US06509472B2
Reaction notes
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