Palladium-Catalyzed Allylic Amidation with N-Heterocycles via sp3 C–H Oxidation

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• 作者：Sandeep R. Vemula ; Dinesh Kumar ; Gregory R. Cook
• 刊名：ACS Catalysis
• 出版年：2016
• 出版时间：August 5, 2016
• 年：2016
• 卷：6
• 期：8
• 页码：5295-5301
• 全文大小：601K
• 年卷期：0
• ISSN：2155-5435

文摘

An atom-economic direct intermolecular allylic amidation of electron-deficient tautomerizable N-heterocycles is reported via allylic C–H activation of terminal olefins with a PdCl₂ catalyst. The reaction did not require any activators (base or Lewis acid) or external ligands and proceeded with high chemo- (N vs O), regio- (linear vs branched), and stereoselectivity (E vs Z) for a variety of N-heterocycles and terminal olefins. Mechanistic investigation and stoichiometric studies validate the sulfoxide-ligand-assisted allylic C–H bond cleavage to form a π-allylpalladium intermediate in the reaction pathway. Excellent selectivity was observed during intermolecular competition demonstrating the differential nucleophilicity of N-heterocycles and differential susceptibility of allyl C–H bond cleavage to form π-allylpalladium complexes directly from terminal olefins.