反应详情

To a solution of 17.7 ml lithium diisopropylamide (2 molar in tetrahydrofuran) in 40 ml tetrahydrofuran was added a solution of 5.61 g but-3-enyloxy-acetic acid ethyl ester [Tetrahedron (1982), 38(17), 2733-9] in 30 ml tetrahydrofuran at −78° C. After stirring for 30 min., a solution of 4.05 g 1-benzenesulfonyl-1H-indole-5-carbaldehyde in 30 ml tetrahydrofuran was added and stirring at −78° C. continued for additional 30 min. Then, the reaction mixture was quenched with 50 ml of saturated of ammonium chloride solution in water and warmed to ambient temperature. It was then extracted with ethyl acetate and the combined organic phases were washed with water, dried over magnesium sulfate and evaporated to give a crude product which was purified by chromatography (silicagel, eluent: gradient of n-heptane/ethyl acetate) to give 4.37 g of 3-(1-benzenesulfonyl-1H-indol-5-yl)-2-but-3-enyloxy-3-hydroxy-propionic acid ethyl ester (mixture of diasteromers) as colorless oil.

1. stirringstirring at −78° C.
2. waitcontinued for additional 30 min
3. customThen, the reaction mixture was quenched with 50 ml of saturated of ammonium chloride solution in water
4. extractionIt was then extracted with ethyl acetate
5. washthe combined organic phases were washed with water
6. dry with materialdried over magnesium sulfate
7. customevaporated
8. customto give a crude product which
9. customwas purified by chromatography (silicagel, eluent: gradient of n-heptane/ethyl acetate)