反应详情

A hexane solution of n-butyl lithium (1.68 M, 13.1 ml, 22.0 mmols) was dropwise added to a THF (80 ml) solution of ethyl 10-(6-bromo-2,3,4,5-tetramethoxyphenyl)-9,9-diethoxycarbonyldecanoate (7.54 g, 12.2 mmols) under a nitrogen stream at −70° C. or lower The reaction mixture was stirred for 15 minutes, and then a THF (10 ml) solution of acetic acid (1.71 g, 28.5 mmols) was dropwise added thereto at −70° C. or lower. After having been allowed to warm to room temperature, the reaction mixture was concentrated in vacuo. A saturated aqueous sodium bicarbonate solution was added to the resulting residue, which was then extracted with ethyl acetate. The organic layer was washed with water and a saturated aqueous sodium chloride solution, then dried, and distilled in vacuo. The resulting crude product was dissolved in ethanol (80 ml), to which was added sodium borohydride (923 mg, 24.4 mmols) with cooling with ice. The reaction mixture was allowed to warm to room temperature, and then stirred for 6 hours. Water was added thereto, and extracted with ethyl acetate. The organic layer was washed with a saturated aqueous sodium chloride solution, and then dried. The solvent was evaporated out in vacuo, and the resulting crude product was isolated through silica gel column chromatography (hexane:ethyl acetate=10:1 to 5:1) to obtain ethyl 8-(2-ethoxycarbonyl-1-hydroxy-4,5,6,7-tetramethoxyindan-2-yl)octanoate (3.77 g).

1. customat −70° C.
2. concentrationthe reaction mixture was concentrated in vacuo
3. additionA saturated aqueous sodium bicarbonate solution was added to the resulting residue, which
4. extractionwas then extracted with ethyl acetate
5. washThe organic layer was washed with water
6. dry with materiala saturated aqueous sodium chloride solution, then dried
7. distillationdistilled in vacuo
8. dissolutionThe resulting crude product was dissolved in ethanol (80 ml), to which
9. temperaturewith cooling with ice
10. temperatureto warm to room temperature
11. stirringstirred for 6 hours
12. extractionextracted with ethyl acetate
13. washThe organic layer was washed with a saturated aqueous sodium chloride solution
14. customdried
15. customThe solvent was evaporated out in vacuo
16. customthe resulting crude product was isolated through silica gel column chromatography (hexane:ethyl acetate=10:1 to 5:1)