反应详情

t-BuLi (3.7 mL of 1.7 M solution in pentane) was added dropwise to a solution of N-(benzensulfonyl)-5-chloroindole (1) (J. Org. Chem. 1981, 46, 3859) (1.5 g, 5.14 mmol) in THF (35 mL) at −70° C., under a nitrogen atmosphere. The mixture was stirred for 15 min, allowed to warm to room temperature over 20 min, cooled to −70° C., and treated with a solution of ethyl iodide (0.84 mL, 10.5 mmol) in dry THF (5 mL). The mixture was stirred at −78° C. for 1 h, allowed to warm to room temperature, stirred for 2 h, poured into ice (15 g), and a saturated aqueous NH4Cl solution and then extracted with ether (3×20 mL). The combined organic extracts were washed with brine, dried (Na2SO4) and evaporated in vacuo to give a residue which was purified by flash chromatography (silica gel, cyclohexane/ethyl acetate, 8:2) and crystallization from ethylacetate/cyclohexane.

1. temperaturecooled to −70° C.
2. stirringThe mixture was stirred at −78° C. for 1 h
3. temperatureto warm to room temperature
4. stirringstirred for 2 h
5. extractiona saturated aqueous NH4Cl solution and then extracted with ether (3×20 mL)
6. washThe combined organic extracts were washed with brine
7. dry with materialdried (Na2SO4)
8. customevaporated in vacuo
9. customto give a residue which
10. customwas purified by flash chromatography (silica gel, cyclohexane/ethyl acetate, 8:2) and crystallization from ethylacetate/cyclohexane