Insights into amine binding to biaryl phosphine palladium oxidative addition complexes and reductive elimination from biaryl phosphine arylpalladium amido complexes via density functional theory
Insights into amine binding to biaryl phosphine palladium oxidative addition complexes and reductive elimination from biaryl phosphine arylpalladium amido complexes via density functional theory
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DOI：
10.1021/ja073747z
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发表时间：
2007-10-03
影响因子：
15
通讯作者：
Buchwald, Stephen L.
中科院分区：
文献类型：
--
作者：
Barder, Timothy E.;Buchwald, Stephen L.
本文报道了L1 Pd（Ar）Cl型单配体氧化加成配合物与多种胺的结合，其中L为2-二环己基膦基-2 '，6'-二甲氧基联苯（SPhos，1）或2-二环己基膦基-2 '，4'，6 '-三异丙基联苯（XPhos，2）。胺与由1和2组成的氧化加成络合物的结合比与较小配体的结合更复杂，因为具有大体积联芳基膦配体的中间体Pd（II）络合物不利于胺与氧化加成络合物的有利构象的结合。此外，还讨论了L型Pd（amido）Ph（其中amido = EtNH，Me 2N，PhNH）配合物还原消除反应的热力学和动力学参数.从这些数据中，我们提出了一个可能的机制（联芳基膦）钯催化的胺化反应，这是比以前认为的更复杂。
We present results on the binding of a variety amines to monoligated oxidative addition complexes of the type L1Pd(Ar)Cl, where L is 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (SPhos, 1) or 2-dicyclohexylphosphino-2',4',6'-tri-ispropylbiphenyl (XPhos, 2). The binding of an amine to oxidative addition complexes composed of 1 and 2 is more complex than with smaller ligands as intermediate Pd(l I) complexes with bulky biaryl phosphine ligands disfavor amine binding to favorable conformations of oxidative addition complexes. Additionally, thermodynamic and kinetic parameters for reductive elimination from complexes of the type L,Pd(amido)Ph (where amido = EtNH, Me2N, PhNH) are discussed. From this data, we suggest a possible mechanism for (biaryl phosphine) Pd-catalyzed amination reactions that is more intricate than previously thought.