Trimethyl borate → HCID 59883201, compound
Reaction equation
[NH2:1][C@H:2]([CH:17]1[CH2:22][CH2:21][CH2:20][CH2:19][CH2:18]1)[C:3]([C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1)([C:5]1[CH:10]=[CH:9][CH:8]=[CH:7][CH:6]=1)[OH:4].[CH3:23][O:24][B:25](OC)OC>O1CCCC1>[CH:17]1([C@@H:2]2[C:3]([C:11]3[CH:12]=[CH:13][CH:14]=[CH:15][CH:16]=3)([C:5]3[CH:10]=[CH:9][CH:8]=[CH:7][CH:6]=3)[O:4][B:25]([O:24][CH3:23])[NH:1]2)[CH2:22][CH2:21][CH2:20][CH2:19][CH2:18]1Participants
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
(R)-2-amino-2-cyclohexyl-1,1-diphenylethanol (59 mg, 0.2 mmol), dry tetrahydrofuran (2 mL) and trimethylborate (27.2 μL, 0.24 mmol) were added to a dry flask and stirred under an atmosphere of nitrogen for 1.5 hours to form a solution of (R)-4-cyclohexyl-5,5-diphenyl-2-methoxy-1,3,2-oxazaborolidine. To this solution was added borane dimethylsulfide complex (100 μL, 1.0 mmol) and the mixture was stirred at room temperature for a further 30 minutes. A solution of 1-tetralone (133 μL, 1.0 mmol) in tetrahydrofuran (5 mL) was added by means of a syringe pump at a rate of 16 mL/min and the reaction was then stirred for a further 1 hour. Thin layer chromatography (silica gel/hexane/ethyl acetate 4:1) showed no starting material. The reaction was quenched by addition of methanol. The solvent was evaporated under vacuum and the residue was dissolved in ethyl acetate and washed 3 times with IN HCl. The ethyl acetate solution was dried over magnesium sulfate, filtered through a plug of silica gel and concentrated to give (S)-1-hydroxy-1,2,3,4-tetrahydronaphthalene with an ee of 96.5%. The enantiomer ratio was determined by HPLC using a Chiralcel OB 25 cm×4.6 mm column with hexane/2-propanol (9:1) mobile phase at 0.5 mL/min at 25° C. Detection with UV was at 254 nm.
Sources & evidence
- ORD record
- ord-8243910bfc22485e98176f5eb61a5e35
- Source dataset
- uspto-grants-2003_01
- Patent number
- US06509472B2
Reaction notes
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