微波协助下方便快捷的溴代芳烃均同偶联反应

Convenient and Efficient Microwave-assisted Homocoupling of Aryl Bromides

芳香族的溴化物在钯催化剂和六丁基二锡存在下经过均同偶联反应能生成二联芳烃。该合成方法在微波协助下只需15min便可得到60％～84％的得率，具有方便、快捷、普适等特点。各种缺电子和富电子芳烃和杂环溴化物，如苯、噻吩、呋喃、吡啶、噻唑和嘧啶的溴化物均易偶联。此方法还适应于稠环芳烃如萘、喹啉、苯并噻吩和吲哚的溴化物，且与羟基、氨基、羧基、醛基、酰基、酯基、硝基、氰基等反应性基团相容。反应是通过溴代芳烃与六丁基二锡先原位生成芳烃有机锡，芳烃有机锡再与溴代芳烃发生Stille偶联反应进行的。

Biaryls and bis-heterocycles can be synthesized conveniently, efficiently, and generally via palladium（0）- catalyzed homocoupling of aryl bromides with hexabutylditin as reductant. This method delivers biaryls in good to excellent yields in 15 min under controlled microwave irradiation. Various bromo-derivatives of electron-rich or electron-poor arches and aromatic heterocycles including benzene, thiophene, furan, pyridine, thiazole, and pyrimidine are easily coupled. This homocoupling method is also applicable to the bromides of fused-ring arenes such as naphthalene, quinoline, benzothiophene, and indole. The procedure is compatible with various reactive functionalities such as hydroxy, amino, carboxyl, formyl, acyl, alkoxycarbonyl, nitro, and cyano groups. The reaction appears to proceed through in situ formation of an aryl tin, followed by a Stille coupling to the aryl bromide.