反应详情

温度

-78 °C

To 3,4-dibromobenzo-1,3-dioxolane (1.54 g, 5.50 mmol) and furan (4 g, 58.8 mmol) in PhMe (55 mL) at −78° C. was added BuLi (2.2 mL, 2.5M in hexanes, 5.5 mmol) dropwise. The reaction was stirred for two hours at −78° C. and the allowed to warm to rt. After 3 hours, MeOH (2 mL) was added and the reaction mixture was poured into water. The organic layer was separated and the aqueous layer was extracted three times with Et2O. The combined organic layers were washed with brine, dried over MgSO4, and concentrated. Recrystallization from hexanes gave 25 (560 mg, 54%) as white crystals). Rf=0.47 on silica gel (30% ethyl acetate:hexanes); mp 111-112° C. (Et2O); IR (KBr, cm−1) 2895, 1455, 1292, 1138, 1038, 1014, 848; 1H NMR (400 MHz, CDCl3) δ 7.02 (2H, dd, J=0.9, 0.9 Hz), 6.82 (2H, s), 5.92 (1H, d, J=1.5 Hz), 5.87 (1H, d, J=1.5 Hz), 5.62 (2H, s); 13C NMR (400 MHz, CDCl3) δ 144.3, 143.3, 103.9, 101.1, 82.4. HRMS calcd for C11H02 (M+): 188.0473. Found: 188.0463.

1. temperatureto warm to rt
2. waitAfter 3 hours
3. customThe organic layer was separated
4. extractionthe aqueous layer was extracted three times with Et2O
5. washThe combined organic layers were washed with brine
6. dry with materialdried over MgSO4
7. concentrationconcentrated
8. customRecrystallization from hexanes