反应详情

温度

-30 °C

To a cooled (−78° C.) solution of mycophenolic acid methyl ester 159A (138 mg, 0.41 mmol) in THF (2.5 mL) was added a THF solution of sodium bis(trimethysilyl)amide (1.0 M, 0.98 mL). After stirring for 30 minutes, a solution of 1,4-dibromo-2-butene (950 mg, 4.1 mmol) in THF (2.5 mL) was added and stirring was continued for 10 minutes. The resulting mixture was warmed to −30° C. and stored at this temperature for 16 hours. The reaction was quenched with saturated aqueous ammonium chloride. The mixture was extracted with ethyl acetate to give, after evaporation of the solvent, a residue which was purified by chromatography on silica gel eluting with ethyl acetate (0% to 40%)/hexanes, affording 2-(4-bromo-but-2-enyl)-6-(4-hydroxy-6-methoxy-7-methyl-3-oxo-1,3-dihydro-isobenzofuran-5-yl)-4-methyl-hex-4-enoic acid methyl ester 159B (150 mg, 78%) as an oil; 1H NMR (300 MHz, CDCl3) δ 1.75 (s, 3H), 2.0-2.4 (m, 8H), 2.62 (m, 1H), 3.37 (d, J=6.6 Hz, 2H), 3.58 (s, 3H), 3.76 (s, 3H), 3.88 (d, J=4.8 Hz, 2H), 5.1-5.3 (m, 3H), 5.67 (brs, 2H), 7.67 (s, 1H) ppm.

1. stirringstirring
2. waitwas continued for 10 minutes
3. waitstored at this temperature for 16 hours
4. customThe reaction was quenched with saturated aqueous ammonium chloride
5. extractionThe mixture was extracted with ethyl acetate
6. customto give
7. customafter evaporation of the solvent
8. customa residue which was purified by chromatography on silica gel eluting with ethyl acetate (0% to 40%)/hexanes