Li Rujuan, Zhan Renqin, Lang Yatao, Li Chao-Jun, Zeng Huiying
The State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University 222 Tianshui Road Lanzhou 730000 P. R. China
Department of Chemistry, and FRQNT Centre for Green Chemistry and Catalysis, McGill University 801 Sherbrooke St. West Montreal QC H3A 0B8 Canada
Chem Sci. 2024 Jul 12;15(32):12900-12905. doi: 10.1039/d4sc02412e. eCollection 2024 Aug 14.
Transition-metal-catalyzed double/triple bond metathesis reactions have been well-established due to the ability of transition-metal catalysts to readily interact with π bonds, facilitating the progression of the entire reaction. However, activating σ-bonds to induce σ-bond metathesis is more challenging due to the absence of π bonds and the high bond energy of σ bonds. In this study, we present a novel photo-induced approach that does not rely on transition metals or photosensitizers to drive C-C and C-N σ-bond metathesis reactions. This method enables the cross-coupling of tertiary amines with α-diketones C-C and C-N single bonds cleavage and recombination. Notably, our protocol exhibits good compatibility with various functional groups in the absence of transition metals and external photosensitizers, resulting in the formation of aryl alkyl ketones and aromatic amides in good to high yields. To gain insights into the mechanism of this pathway, we conducted controlled experiments, intermediate trapping experiments, and DFT (Density Functional Theory) calculations. This comprehensive approach allowed us to elucidate the detailed mechanism underlying this transformative reaction.
过渡金属催化的双键/三键复分解反应已得到充分确立，这是因为过渡金属催化剂能够轻松地与π键相互作用，从而促进整个反应的进行。然而，由于不存在π键且σ键的键能较高，激活σ键以引发σ键复分解反应更具挑战性。在本研究中，我们提出了一种新颖的光诱导方法，该方法不依赖过渡金属或光敏剂来驱动碳-碳和碳-氮σ键复分解反应。这种方法能够实现叔胺与α-二酮的交叉偶联——碳-碳和碳-氮单键的断裂与重组。值得注意的是，我们的方案在没有过渡金属和外部光敏剂的情况下，与各种官能团具有良好的兼容性，从而以良好到高的产率形成芳基烷基酮和芳香酰胺。为了深入了解该途径的机制，我们进行了对照实验、中间体捕获实验和密度泛函理论（DFT）计算。这种综合方法使我们能够阐明这种转化反应背后的详细机制。
