O[CH2:2][CH2:3][C:4]1([CH3:24])[CH2:8][C:7]2[C:9]([CH3:23])=[C:10]([NH:15][C:16](=[O:22])[O:17][C:18]([CH3:21])([CH3:20])[CH3:19])[C:11]([CH3:14])=[C:12]([CH3:13])[C:6]=2[O:5]1.C(Br)(Br)(Br)[Br:26].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>O1CCCC1>[Br:26][CH2:2][CH2:3][C:4]1([CH3:24])[CH2:8][C:7]2[C:9]([CH3:23])=[C:10]([NH:15][C:16](=[O:22])[O:17][C:18]([CH3:21])([CH3:20])[CH3:19])[C:11]([CH3:14])=[C:12]([CH3:13])[C:6]=2[O:5]1To a solution of tert-butyl [2,3-dihydro-2-(2-hydroxyethyl)-2,4,6,7-tetramethylbenzofuran-5-yl]carbamate (7.7 g) and carbon tetrabromide (8.0 g) in tetrahydrofuran (80 mL) was added 6.3 g of triphenylphosphine under ice-cooling and the mixture was stirred for 30 minutes. This reaction mixture was filtered and the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography (hexane/ethyl acetate=97:3 to 4:1) to provide 7.5 g of the title compound. Yield 82%.
Wird geladen…