反应详情

温度

55 °C

To a solution of 1.75 g of the crude title compound of Step D in 6 mL of anhydrous dimethylsulfoxide ("DMSO") under argon, 3.0 g of anhydrous trimethylamine N-oxide (prepared as described in Soderquist et al., Tet. Letters., 27, 3961 (1986); this compound is also commercially available) were added and the mixture stirred at 55° C. for 12 hrs. The mixture was then cooled and added to 100 mL of ice/water and extracted with 3×50 mL of EtOAc. The combined organic extracts were washed once with 100 mL of brine and dried and evaporated. The residue was chromatographed on 100 mL of silica gel using Hexanes/EtOAc 6:1 to afford 0.86 g (81.5% for two steps) of the title compound of this step as a white solid.

1. additionwere added
2. temperatureThe mixture was then cooled
3. extractionextracted with 3×50 mL of EtOAc
4. washThe combined organic extracts were washed once with 100 mL of brine
5. customdried
6. customevaporated
7. customThe residue was chromatographed on 100 mL of silica gel