反应详情

温度

-78 °C

2-(4,5-Dibromo-2-thienyl)-1,3-dioxolane (for a synthesis, see J Org Chem, 1976, 41, 8) (6.05 g, 19.2 mmol) was dissolved in dry THF (500 ml) and cooled to −78° C. After 15 min the reaction mixture was treated with 3-(tert-butyldimethylsilyloxy)-1-iodopropane (6.3 g, 1.1 equiv.) (for a synthesis, see J. Chem. Soc. Perkin Trans. 1, 1190, 1111). After a further 15 min. the cooling bath was removed and the reaction allowed warm to room temperature overnight. The reaction was quenched with saturated aqueous ammonium chloride, and partitioned between ethyl acetate and water. The organic phase was dried over anhydrous magnesium sulphate and evaporated. The residue was chromatographed on silica gel eluting with 0-10% ethyl acetate in hexane. Product-containing fractions were combined and evaporated to a colourless oil) 5.61 g. This was dissolved in THF (100 ml) and treated with tetra-n-butyl ammonium fluoride (2M solution in THF, 16 ml) and stirred at room temperature overnight. The solvent was evaporated and the residue partitioned between water and ethyl acetate. The organic phase was separated, washed with brine, dried over anhydrous magnesium sulphate and evaporated. The residue was chromatographed on silica gel eluting with 1-100% ethyl acetate in hexane, to afford the title compound (2.48 g, 44%).

1. customfor a synthesis
2. customAfter a further 15 min. the cooling bath was removed
3. temperaturethe reaction allowed warm to room temperature overnight
4. customThe reaction was quenched with saturated aqueous ammonium chloride
5. custompartitioned between ethyl acetate and water
6. dry with materialThe organic phase was dried over anhydrous magnesium sulphate
7. customevaporated
8. customThe residue was chromatographed on silica gel eluting with 0-10% ethyl acetate in hexane
9. customevaporated to a colourless oil) 5.61 g
10. dissolutionThis was dissolved in THF (100 ml)
11. additiontreated with tetra-n-butyl ammonium fluoride (2M solution in THF, 16 ml)
12. customThe solvent was evaporated
13. customthe residue partitioned between water and ethyl acetate
14. customThe organic phase was separated
15. washwashed with brine
16. dry with materialdried over anhydrous magnesium sulphate
17. customevaporated
18. customThe residue was chromatographed on silica gel eluting with 1-100% ethyl acetate in hexane