Trimethyl borate → HCID 69930837, compound

HRID 1635611Notes

Reaction equation

HRID 1635611 reaction equation
[NH2:1][C@@H:2]([CH:21]1[CH2:26][CH2:25][CH2:24][CH2:23][CH2:22]1)[C:3]([C:13]1[CH:18]=[CH:17][C:16]([O:19][CH3:20])=[CH:15][CH:14]=1)([C:5]1[CH:10]=[CH:9][C:8]([O:11][CH3:12])=[CH:7][CH:6]=1)[OH:4].[CH3:27][O:28][B:29](OC)OC>O1CCCC1>[CH:21]1([C@H:2]2[C:3]([C:5]3[CH:6]=[CH:7][C:8]([O:11][CH3:12])=[CH:9][CH:10]=3)([C:13]3[CH:18]=[CH:17][C:16]([O:19][CH3:20])=[CH:15][CH:14]=3)[O:4][B:29]([O:28][CH3:27])[NH:1]2)[CH2:26][CH2:25][CH2:24][CH2:23][CH2:22]1

Participants

4

Reactant 2

HCID 8470Trimethyl borateHCID 69930854HCID 69930854, compound

Product 1

HCID 69930837HCID 69930837, compound

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

(S)-2-amino-2-cyclohexyl-1,1-bis-(4-methoxyphenyl)ethanol (71.1 mg, 0.2 mmol), dry tetrahydrofuran (2 mL) and trimethylborate (27.2 μL, 0.24mmol) were added to a dry flask and stirred under an atmosphere of nitrogen for 1.5 hours to form a solution of (S)-4-cyclohexyl-5,5-bis-(4-methoxyphenyl)-2-methoxy-1,3,2-oxazaborolidine. Borane dimethylsulfide complex (100 μL, 1.0 mmol) was added to this solution and the mixture was stirred at room temperature for a further 30 minutes. A solution of 3,5-(bistrifluoromethyl)-acetophenone (180 μL, 1.0 mmol) in tetrahydrofuran (3 mL) was added by means of a syringe pump at a rate of 9 mL/min and the reaction then stirred for a further 1.5 hours. Thin layer chromatography (silica gelhexane/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 1N HCl. The ethyl acetate solution was dried over magnesium sulfate, filtered through a plug of silica gel and concentrated to give (R)-1-[3,5-(bistrifluoromethyl)phenylethanol. The enantiomer ratio was determined by HPLC using a Chiralcel OD 25 cm×4.6 mm column with hexane/2-propanol (97: 3) mobile phase at 0.7 mL/min at 25° C. Detection with UV was at 254 nm.

Sources & evidence

ORD record
ord-46ed2064282e4cc6bfc14dd492c406e9
Source dataset
uspto-grants-2003_01
Patent number
US06509472B2

Reaction notes

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