Palladium-Catalyzed Homocoupling of Highly Fluorinated Arylboronates: Studies of the Influence of Strongly vs Weakly Coordinating Solvents on the Reductive Elimination Process
作者:Yudha P. Budiman、Arumugam Jayaraman、Alexandra Friedrich、Florian Kerner、Udo Radius、Todd B. Marder
DOI:10.1021/jacs.9b11871
日期:2020.4.1
C-C reductive elimination from [PdL2(C6F5)2] to form polyfluorinated biaryls has been a challenge for over 50 years. Thus, palladium-catalyzed homocoupling of arylboronates (ArF-Bpin) containing two ortho-fluorine substituents is very difficult as the reaction typically stops at the [PdL2(ArF)2] stage after two transmetalation steps. The transmetalated complexes cis-[Pd(MeCN)2(C6F5)2] (3a), cis-[Pd(MeCN)2(2
50 多年来,从 [PdL2(C6F5)2] 中还原消除 CC 以形成多氟联芳基化合物一直是一项挑战。因此,钯催化的含有两个邻氟取代基的芳基硼酸酯 (ArF-Bpin) 的均偶联非常困难,因为反应通常在两个金属转移步骤后在 [PdL2(ArF)2] 阶段停止。金属转移配合物 cis-[Pd(MeCN)2(C6F5)2] (3a)、cis-[Pd(MeCN)2(2,4,6-C6F3H2)2] (3b) 和 cis-[Pd(MeCN) )2(2,6-C6F2H3)2](3e) 已从 ArF-Bpin 与 Pd(OAc)2 在乙腈溶剂中的反应中分离出来,没有观察到均偶联。然而,只要不存在辅助配体或配位溶剂,催化均偶联在“弱配位”芳烃溶剂中顺利进行。