Methanol → (R)-tert-Butyl 5-hydroxy-7-methyl-8-(trifluoromethyl)-2,3,4,5-tetrahydro-1H-benzo[b]azepine-1-carboxylate

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Reaction Conditions

Reaction Steps

Add a solution of borane dimethylsulfide complex (3.8 mL, 7.58 mmol, 2 M in tetrahydrofuran) dropwise to a solution of (S)-2-methyl-CBS-oxazaborolidine (9.5 mL, 9.48 mmol, 1M in toluene) in dichloromethane (20 mL) at −30° C. under nitrogen. Stir the mixture for 30 min and add a solution of tert-butyl 7-methyl-5-oxo-8-trifluoromethyl-2,3,4,5-tetrahydrobenzo[b]azepine-1-carboxylate (2.17 g, 6.32 mmol) in dichloromethane (20 mL) dropwise and warm the mixture slowly to 0° C. Pour the mixture into methanol (200 mL) at −20° C. and slowly warm the stirring mixture to room temperature over 1 h. Remove the solvents under reduced pressure and purify the residue by column chromatography on silica gel, eluting with ethyl acetate/hexanes (1:2), to provide the title compound as a colorless oil (1.65 g, 76%). APCI MS m/z 345 (M+H)+.

Provenance & Evidence