反应详情

温度

110 °C

Lithium bromide (19.2 g, 220.2 mmol) was added to a stirred solution of ditosylate (42) (40.0 g, 88.1 mmol) in dimethyl sulfoxide (200 mL) under an atmosphere of argon. The mixture was heated at 110° C. for 8 hours then at 120° C. for 1.75 hours. The mixture was diluted with water (500 mL) then extracted with tert-butyl methyl ether (4×250 mL). The organic phase was washed with water (3×250 mL) then brine (250 mL), dried (MgSO4), filtered and reduced in vacuo to leave an orange solid. Recrystallisation from methanol (100 mL) gave bromotosylate (47) (17.47 g, 55%) as a pale yellow solid. [α]D15+49.5° (c=11.7, CHCl3).

1. extractionthen extracted with tert-butyl methyl ether (4×250 mL)
2. washThe organic phase was washed with water (3×250 mL)
3. dry with materialbrine (250 mL), dried (MgSO4)
4. filtrationfiltered
5. customto leave an orange solid
6. customRecrystallisation from methanol (100 mL)