Ozone → [1-(5-Bromo-2-fluoro-phenyl)-1-difluoromethyl-3-hydroxy-propyl]-carbamic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

A suspension of [1-(5-bromo-2-fluoro-phenyl)-1-difluoromethyl-but-3-enyl]-carbamic acid tert-butyl ester (5.11 g, 12.96 mmol) and NaHCO3 (1.63 g, 19.44 mmol) in 90 ml DCM and 30 ml MeOH was cooled to −75° C. A mixture of O3 in oxygen gas was introduced till the blue color persisted. The excess ozone was removed by bubbling through oxygen gas for 10 minutes. NaBH4 (0.981 g, 25.9 mmol) was added as a solid in three portions. The mixture was stirred 10 min at −75° C. and then allowed to warm to 0° C. After 30 min the mixture was poured onto ice-cold 1N HCl and extracted with TBME. The organic phase was washed with 1N HCl, brine, dried with MgSO4.H2O and evaporated. Chromatography on silica gel (hexanes/15-35% EtOAc) provided 4.75 g of the title compound as a colorless resin.

Provenance & Evidence