反应详情

温度

-45 °C

To a solution of lithium diisopropylamide (prepared from 13 ml of diisopropylamine and 54 ml of 1.6M n-BuLi in hexanes in 200 ml of anhydrous THF at 0° C.) at -72° C. was added slowly 2-(s)-t-butyl-5-(s)-methyl-1,3-dioxolan-4-one (12.95 g, 81.9 mmol, Tetrahedron, 1984, 40, 1313) at such a rate as to maintain the internal temperature below -60° C. and the mixture was aged at -72° C. for an hour. 1,1,1-Trifluoro-2-iodoethane (25 g, 119 mmol) was added quickly, the reaction temperature increased to -45° C. and the mixture was aged at -72° C. for 45 min. and then allowed to warm up to -20° C. over 20 min. Saturated aq. NH4Cl was then added and the product was extracted in i-PrOAc, dried over Na2SO4, concentrated and distilled under reduced pressure to afford 7.51 g of a brown oil BP 90° C./20 mm Hg.

1. temperatureto maintain the internal temperature below -60° C.
2. waitthe mixture was aged at -72° C. for an hour
3. temperatureto warm up to -20° C. over 20 min
4. extractionthe product was extracted in i-PrOAc
5. dry with materialdried over Na2SO4
6. concentrationconcentrated
7. distillationdistilled under reduced pressure