Sodium borohydride → HCID 58594757, compound

Participants

Reaction Steps

Solid sodium borohydride (2.50 g, 66 mmol) was added in small portions within 15 min. into a magnetically stirred, ice-cooled solution of (11R) and (11S)-11-{[(4R)-2,2-dimethyl-1,3-dioxolan-4-yl]methyl}-8-fluoro-5,11-dihydro-10H-dibenzo[a,d]cyclohepten-10-one (reaction mixture of intermediate 7 and 8 before separation) (65:35, 1278 mg, 3.75 mmol) in isopropanol (160 mL) and 0.5 M phosphate buffer (pH 7, 63 mL). Reaction mixture was stirred at 0° C. for additional 15 min., quenched with saturated aqueous NH4Cl (30 mL); organic phase was separated, aqueous solution extracted with ether (2×30 mL), combined organics washed with water (2×50 mL), then brine (50 mL), dried (MgSO4), evaporated in vacuo, to furnish crude mixture of two alcohols. HPLC separation (Waters 515 pump, 2 mL injection loop, Merck Hibar® 250×25 mm column LiChrosorb® SI 60 7 μm, Waters 2410 refractive index detector, EtOAc-hexane 30:70, 15 mL/min) gave pure intermediate 13 (10S,11S)-11-{[(4R)-2,2-dimethyl-1,3-dioxolan-4-yl]methyl}-8-fluoro-10,11-dihydro-5H-diben-zo[a,d]cyclohepten-10-ol (449 mg, 1.31 mmol, 35%) as a colorless oil.

Provenance & Evidence