Hydrogen Peroxide → rac-tert-butyl (4R,5R)-4-fluoro-5-hydroxyazepane-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a tert-butyl 4-fluoro-5-oxoazepane-1-carboxylate (20.0 g, 86.5 mmol) was dissolved in THF (430 mL) solution and the solution was cooled to −5° C. L-Selectride (112 mL, 112 mmol, 1.0 M in THF) was added via syringe. The mixture was gradually warmed to ambient temperature over 3 hours and stirred for an additional 20 hours. The resulting cloudy mixture was diluted with 110 mL of MeOH, followed by addition of NaOH (355 mL, 355 mmol, 1.0M aqueous). The mixture was cooled in a water bath and H2O2 (80.4 mL, 709 mmol, 30% aqueous) was added carefully via addition funnel over 30 minutes. The mixture was stirred vigorously for 1 hour. The mixture was diluted with water and extracted with EtOAc (3×200 mL). The combined organic layers were washed with water and 1N KHSO4 (2×150 mL), and the combined aqueous phases were back extracted with EtOAc (200 mL). The combined organic layers were washed with saturated aqueous NaHCO3, dried over Na2SO4, filtered and concentrated. The crude product was purified via column chromatography (15% to 60% EtOAc/hexanes) to provide the product as a thick colorless oil which slowly became a white solid (13.9 g, 69%; diastereomeric ratio (dr): ˜7:1 trans:cis).

Provenance & Evidence