The ligand‐promoted palladium‐catalyzed arylation of alkynes with arenes without directing group is able to furnish alkenyl chlorides via a 1,4‐chlorine migration or trisubstituted alkenes. This reaction is challenging due to bidentate N, N ligand and electron‐neutral arenes have rarely been reported to afford good yields. Intrigued by the novel strategy, we carried out density functional theory calculations to unravel the ligand effects and origins of substituent‐controlled chemoselectivity of the C–H functionalization reactions. For the n‐propyl‐substituted alkyne system, CMD process is identified as the rate‐determining step. And the chemoselectivity is controlled by oxidative addition with the C–Cl bond cleavage and protonation process. While for 3,5‐dimethylphenyl‐substituented alkyne system, the dominant pathway turns to the protonation process. The electrostatic attractions, repulsive force and aryl substituent effects jointly result in reverse chemoselectivity. Compared with the L2 ligand, the bidentate ligand L1 reacts with palladium acetate to form a different stable square‐planer species. The steric repulsion are found to be mainly responsible for the absence of products using the L2 ligand, which is different from previous reports.

中文翻译：

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炔烃与炔烃的配体促进的CH烯基化的机理研究：一项计算研究

炔烃与芳烃的配体促进的钯催化的芳基化而没有芳基，能够通过1,4-氯的迁移或三取代的烯烃提供链烯基氯化物。由于很少有双齿N，N配体和电子中性芳烃具有良好的收率，因此该反应具有挑战性。被这种新颖的策略所吸引，我们进行了密度泛函理论计算，以揭示配体效应和CH功能化反应的取代基控制的化学选择性的起源。对于正丙基取代的炔烃体系，CMD工艺被确定为决定速率的步骤。化学选择性是通过C–Cl键裂解和质子化过程中的氧化加成来控制的。而对于3,5-二甲基苯基取代的炔烃体系，主导途径转向质子化过程。静电引力，排斥力和芳基取代基效应共同导致反向化学选择性。与L2配体相比，双齿配体L1与乙酸钯反应形成不同的稳定方平面物质。发现空间排斥主要是使用L2配体的产物不存在的原因，这与以前的报道不同。