反应详情

A solution of p-toluenesulfonyl chloride (24.8 g, 130 mmol) in pyridine (150 mL) was added to a stirred solution of isomannide (40) (19.0 g, 130 mmol) in pyridine (150 mL) over 1 hour at 0° C. then stirred at ambient temperature for 1 hour. The mixture was poured onto iced-water (1 L) then extracted with dichloromethane (3×300 mL). The organic phase washed with brine (300 mL), dried (MgSO4), filtered and reduced in vacuo to leave a residue. Flash chromatography over silica, eluting with ethyl acetate:heptane mixtures 0:100 to 50:50 gave monotosylate (50) (23.4 g, 60%) as a white solid.

1. extractionthen extracted with dichloromethane (3×300 mL)
2. washThe organic phase washed with brine (300 mL)
3. dry with materialdried (MgSO4)
4. filtrationfiltered
5. customto leave a residue
6. washFlash chromatography over silica, eluting with ethyl acetate