反应详情

A mixture of 3-isopropoxy-4-tributylstannyl-cyclobut-3-ene-1,2-dione (4.68 g; preparable as described in Liebeskind and Fengl, Journal of Organic Chemistry (1990), Vol.55, pp 5359/5364), 1-bromo-2-iodobenzene (3.54 g), dry dimethylformamide (15 ml), tetrakis(triphenylphosphine)palladium(0) (0.606 g) and cuprous iodide (0.196 g) was stirred under a nitrogen atmosphere at ambient temperature for approximately 2.5 hours then kept at ambient temperature for 3 days. Diethyl ether (225 ml) was added, and the mixture obtained was washed with saturated aqueous ammonium chloride (225 ml) and then with 10% aqueous potassium fluoride solution (3×225 ml). The organic phase was filtered through a silica bed (5 cm diameter×1 cm depth), and the collected solids were washed with diethyl ether (50 ml). The resulting orange filtrate and washings were combined and evaporated to give a semi-solid brown oil, which was purified by flash chromatography on silica gel (loading in dichloromethane and eluting with 20% diethyl ether in petroleum ether (b.p. 40°-60° C.)) to give the intermediate compound 3-(2-bromophenyl)-4-isopropoxycyclobut-3-ene-1,2-dione, as a yellow oil (2.16 g).

1. waitthen kept at ambient temperature for 3 days
2. customthe mixture obtained
3. washwas washed with saturated aqueous ammonium chloride (225 ml)
4. filtrationThe organic phase was filtered through a silica bed (5 cm diameter×1 cm depth)
5. washthe collected solids were washed with diethyl ether (50 ml)
6. customevaporated
7. customto give a semi-solid brown oil, which
8. customwas purified by flash chromatography on silica gel (loading in dichloromethane and eluting with 20% diethyl ether in petroleum ether (b.p. 40°-60° C.))