华东理工大学Jie Zhao小组在研究中取得进展。他们的最新研究利用非均相铑单原子位催化剂实现化学选择性卡宾 N–H键插入。这一研究成果于2024年4月7日发表在国际顶尖学术期刊《美国化学会杂志》上。

在该研究中，该课题组提出了一种合成铑单原子位点催化剂(Rh-SA)的有效策略，该催化剂将Rh原子包围在三个氮原子和一个磷原子中，并掺杂在碳载体中。负载率仅为0.15 mol %的Rh-SA催化剂，对多种苯胺和杂芳胺与重氮酯结合的异相羰基插入具有优异的催化性能。

重要的是，多相催化剂选择性地将具有多个亲核基团的苯胺衍生物转化为单个N-H插入异构体，而流行的均相催化剂Rh₂(OAc)₄则产生了过度官能化副产物的混合物。此外，该反应对一组立体电子不同的重氮酯对N-H键插入获得了相似选择性，突出了这种多相催化方法的普遍适用性。

根据密度泛函理论计算，Rh-SA催化剂的选择性归因于插入势垒和载体中磷原子协助的加速质子转移。总的来说，这项研究强调了单原子位点催化在有机合成中，作为一种强大的互补工具的潜力。

据介绍，过渡金属催化的氮-氢键的卡宾插入反应，已成为构建碳-氮键的最稳定和通用的方法。虽然均相催化金属碳烯N-H插入已经取得了重大进展，但由于金属碳烯中间体的高亲电性，该领域的化学选择性控制仍然具有挑战性。

附：英文原文

Title: Heterogeneous Rhodium Single-Atom-Site Catalyst Enables Chemoselective Carbene N–H Bond Insertion

Author: Yuanjun Chen, Ruixue Zhang, Zhiwen Chen, Jiangwen Liao, Xuedong Song, Xiao Liang, Yu Wang, Juncai Dong, Chandra Veer Singh, Dingsheng Wang, Yadong Li, F. Dean Toste, Jie Zhao

Issue&Volume: April 7, 2024

Abstract: Transition-metal-catalyzed carbene insertion reactions of a nitrogen–hydrogen bond have emerged as robust and versatile methods for the construction of C–N bonds. While significant progress of homogeneous catalytic metal carbene N–H insertions has been achieved, the control of chemoselectivity in the field remains challenging due to the high electrophilicity of the metal carbene intermediates. Herein, we present an efficient strategy for the synthesis of a rhodium single-atom-site catalyst (Rh-SA) that incorporates a Rh atom surrounded by three nitrogen atoms and one phosphorus atom doped in a carbon support. This Rh-SA catalyst, with a catalyst loading of only 0.15 mol %, exhibited exceptional catalytic performance for heterogeneous carbene insertion with various anilines and heteroaryl amines in combination with diazo esters. Importantly, the heterogeneous catalyst selectively transformed aniline derivatives bearing multiple nucleophilic moieties into single N–H insertion isomers, while the popular homogeneous Rh2(OAc)4 catalyst produced a mixture of overfunctionalized side products. Additionally, similar selectivities for N–H bond insertion with a set of stereoelectronically diverse diazo esters were obtained, highlighting the general applicability of this heterogeneous catalysis approach. On the basis of density functional theory calculations, the observed selectivity of the Rh-SA catalyst was attributed to the insertion barriers and the accelerated proton transfer assisted by the phosphorus atom in the support. Overall, this investigation of heterogeneous metal-catalyzed carbene insertion underscores the potential of single-atom-site catalysis as a powerful and complementary tool in organic synthesis.

DOI: 10.1021/jacs.4c01408

Source: https://pubs.acs.org/doi/full/10.1021/jacs.4c01408