Methanol → (4s)-5-(4-Fluorophenyl)-6-{(r)-hydroxy[4-(trifluoromethyl)phenyl]methyl}-7-isopropyl-2,2-di-methylchroman-4-ol

Participants

Reaction Steps

340 μl (1.89 mmol) of borane/N,N-diethylaniline complex are added slowly to a solution of 10.58 mg (70 μmol) of (1R,2S)-1-aminoindan-2-ol in ±1 ml of tetrahydrofuran, and the mixture is stirred for another 30 min. A solution of 230 mg (0.47 mmol) of rac-5-(4-fluorophenyl)-6-{hydroxy[4-(trifluoromethyl)phenyl]methyl}-7-isopropyl-2,2-dimethyl-2,3-dihydro-4H-chromen-4-one (Example 21A) in 11 ml of tetrahydrofuran are then very slowly added dropwise, and the mixture is stirred overnight. Methanol is then added, and the solvent is removed under reduced pressure. The residue is taken up in ethyl acetate and washed in each case twice with 1 M hydrochloric acid and saturated sodium bicarbonate solution and once with saturated sodium chloride solution. The organic phase is dried over sodium sulfate and then concentrated under reduced pressure. Purification of the residue by column chromatography on silica gel (mobile phase: gradient cyclohexane/dichloromethane/ethyl acetate 40:40:1→2:2:1) gives the diastereomerically pure target compounds.

Provenance & Evidence