College of Chemistry and Materials Science, Hebei Key Laboratory of Inorganic Nano-materials, Hebei Normal University, Shijiazhuang, 050024, China.
Dalton Trans. 2023 Apr 4;52(14):4517-4525. doi: 10.1039/d3dt00158j.
In gold(I) catalysis, the activation of Au(I) chloride catalysts chloride abstraction and noncovalent interactions has become a research focus in organometallic catalysis. In this work, taking halogen bond donors (CHINO, CFI, CHOI) as activators for a Au(I) chloride catalyst (PhPAuCl), the mechanism of the cyclization reaction of propargylic amide was investigated. It was found that there are two activation modes as design principles to obtain the catalytically active species PhPAu: the halogen bond donors activate the Cl atoms of PhPAuCl to form X-I⋯Cl (X = C, N) classical halogen bonds and activate the Au atoms of PhPAuCl to form X-I⋯Au (X = C, N) metal-involved halogen bonds. For the two activation modes, the mechanism of the cyclization reaction of propargylic amide has pathways: the chloride abstraction process of the first step and the 5-/6- cyclization process of the second step. Both activation modes show good activity for the cyclization reaction with the activation ability of classical halogen bonds being slightly stronger than that of the metal-involved halogen bonds, which is consistent with the strength of the X-I⋯Cl halogen bonds being slightly stronger than that of the X-I⋯Au halogen bonds. Therefore, both metal-involved halogen bonds and classical halogen bonds have important development prospects for the activation of catalysts in gold(I) catalysis.
在金（I）催化中，金（I）氯化物催化剂的活化——包括氯原子的夺取和非共价相互作用——已成为有机金属催化研究的焦点。在这项工作中，我们选择卤素键供体（CHINO、CFI、CHOI）作为金（I）氯化物催化剂（PhPAuCl）的活化剂，研究了炔丙酰胺环化反应的机理。结果发现，有两种活化模式可作为设计原则来获得催化活性物种 PhPAu：卤素键供体可以活化 PhPAuCl 的 Cl 原子，形成 X-I⋯Cl（X = C、N）经典卤素键，并活化 PhPAuCl 的 Au 原子，形成 X-I⋯Au（X = C、N）金属参与的卤素键。对于这两种活化模式，炔丙酰胺的环化反应具有两条反应途径：第一步的氯原子夺取过程和第二步的 5-/6-环化过程。两种活化模式对环化反应都表现出良好的活性，其中经典卤素键的活化能力略强于金属参与的卤素键，这与 X-I⋯Cl 卤素键的强度略强于 X-I⋯Au 卤素键的强度一致。因此，金属参与的卤素键和经典卤素键在金（I）催化中对催化剂的活化都具有重要的发展前景。
