Nickel-Catalyzed Amination of Aryl Thioethers: A Combined Synthetic and Mechanistic Study
Nickel-Catalyzed Amination of Aryl Thioethers: A Combined Synthetic and Mechanistic Study
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DOI：
10.1021/acscatal.0c00393
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发表时间：
2020-04-17
期刊：
影响因子：
12.9
通讯作者：
Morandi, Bill
中科院分区：
文献类型：
--
作者：
Bismuto, Alessandro;Delcaillau, Tristan;Morandi, Bill
本文报道了一种用于催化Buchwald-Hartwig胺化芳基硫醚的镍-1,2-二（双环己基膦）乙烷（型）配合物。该方案显示了广泛的适用性与各种不同的官能团在催化条件下耐受。广泛的有机金属和动力学研究支持镍(0)-镍（II）转化途径，并揭示氧化加成络合物是催化循环的静息状态。所有分离的中间体都被证明是这种转化的催化和动力学催化剂。在较低温度下，通过另一种合成有机金属途径成功地合成了瞬变金属过渡中间体，从而允许对C-N键还原消除步骤进行原位核磁共振研究。本研究解决了控制镍催化Buchwald-Hartwig胺化过程机制的关键因素，从而提高了对这类重要反应的理解。
Herein, we report a nickel-1,2-bis-(dicyclohexylphosphino)ethane (dcype) complex for the catalytic Buchwald-Hartwig amination of aryl thioethers. The protocol shows broad applicability with a variety of different functional groups tolerated under the catalytic conditions. Extensive organo-metallic and kinetic studies support a nickel(0)-nickel(II) pathway for this transformation and revealed the oxidative addition complex as the resting state of the catalytic cycle. All the isolated intermediates have proven to be catalytically and kinetically competent catalysts for this transformation. The fleeting transmetalation intermediate has been successfully synthesized through an alternative synthetic organometallic pathway at lower temperature, allowing for in situ NMR study of the C-N bond reductive elimination step. This study addresses key factors governing the mechanism of the nickel-catalyzed Buchwald-Hartwig amination process, thus improving the understanding of this important class of reactions.