反应详情

温度

0 °C

4-Hydroxy-indole-1,2-dicarboxylic acid 1-tert-butyl ester 2-ethyl ester (2) (5.2 g, 17.2 mmol), (6-ethoxy-benzofuran-3-yl)-methanol (28a) (3.3 g, 17.2 mmol) and triphenylphosphine (5.4 g, 20.6 mmol) are dissolved in 30 ml of THF and cooled to 0° C. Then 40% ethyl azodicarboxylate solution in THF (9 ml, 20.6 mmol) is added drop wise. After completed addition the mixture is stirred for 16 h (TLC control) at rt. Then the mixture is evaporated under reduced pressure. The residue is diluted with ethyl acetate, washed sat. NaHCO3- and NaCl-solution, and dried over Na2SO4. The crude product is purified by Flash-chromatography (ethyl acetate/hexanes (1:9), silicagel).

1. additionaddition the mixture
2. customThen the mixture is evaporated under reduced pressure
3. additionThe residue is diluted with ethyl acetate
4. washwashed sat. NaHCO3- and NaCl-solution
5. dry with materialdried over Na2SO4
6. customThe crude product is purified by Flash-chromatography (ethyl acetate/hexanes (1:9), silicagel)