The Suzuki–Miyaura cross-coupling reaction of 2-bromo-1,3-bis(trifluoromethyl)benzene with arylboronic acids was evaluated and determined to suffer from the formation of large amounts of boronic acid homocoupling products in conjunction with dehalogenation. Homocoupling product formation in this process likely occurs through a rare protonolysis/second transmetalation event rather than by the well-established mechanism requiring the involvement of O2. The scope of this boronic acid homocoupling reaction was investigated and shown to predominate with electron-deficient arylboronic acids. Finally, a good yield of cross-coupling products could be obtained by employing dicyclohexyl(2′,6′-dimethoxybiphenyl-2-yl)phosphine (SPhos) as the ligand.

中文翻译：

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利用受阻氟化芳烃在 Suzuki-Miyaura 交叉偶联反应中鉴定出令人惊讶的硼酸均偶联过程

对 2-溴-1,3-双（三氟甲基）苯与芳基硼酸的 Suzuki-Miyaura 交叉偶联反应进行了评估，并确定在脱卤过程中会形成大量硼酸均偶联产物。该过程中的均偶联产物形成可能通过罕见的质子分解/第二次金属转移事件发生，而不是通过需要 O2 参与的完善机制。研究了这种硼酸均偶联反应的范围，并显示出以缺电子芳基硼酸为主。最后，通过使用二环己基（2'，6'-二甲氧基联苯-2-基）膦（SPhos）作为配体，可以获得良好的交叉偶联产物。