Microwave-assisted aqueous Suzuki cross-coupling reactions
Microwave-assisted aqueous Suzuki cross-coupling reactions
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DOI：
10.1021/jo982135h
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发表时间：
1999-05-28
影响因子：
3.6
通讯作者：
Schotten, T
中科院分区：
文献类型：
--
作者：
Blettner, CG;König, WA;Schotten, T
溴代、碘代和三氟甲磺酸对位取代的苯甲酸酯的聚乙二醇酯在水中在“无配体”乙酸钯催化下与芳基硼酸顺利地交叉偶联（Suzuki 反应）。该反应在没有有机共溶剂的情况下在常规热条件（70℃，2小时）和微波照射（75W，2-4分钟）下进行。聚合物载体在两种反应条件下均保持稳定。传统的热条件会引起酯裂解（高达 45%），而采用微波条件时，这种副反应会受到抑制。在这些条件下，九氟芳基酯可产生相当好的收率。在微波辐射（4 分钟，75 W）下，非聚合物结合的芳基卤化物在水/聚乙二醇混合物中以良好至优异的产率形成联芳基。
The poly(ethylene glycol) ester of bromo-, iodo-, and triflate-para-substituted benzoates are smoothly cross-coupled with aryl boronic acids (Suzuki reaction) under "ligandless" palladium acetate catalysis in water. The reaction proceeds without organic cosolvent under conventional thermal conditions (70 degrees C, 2 h) and under microwave irradiation (75 W, 2-4 min). The polymeric support remains stable under both reaction conditions. Whereas conventional thermal conditions induced ester cleavage (up to 45%), this side reaction is suppressed when microwave conditions are employed. Aryl nonaflates give fair yields under these conditions. Non-polymer-bound aryl halides form biaryls in good to excellent yields in water/poly(ethylene glycol) mixtures under microwave irradiation (4 min, 75 W).