College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, P. R. China.
Org Biomol Chem. 2020 Jan 22;18(3):530-537. doi: 10.1039/c9ob02508a.
A phosphine-mediated deoxygenative condensation of 1,2-dicarbonyl compounds such as aroylformates, α-diketones, and isatins with arylazocarboxylates has been developed for a facile synthesis of N-aryl-N-acyl hydrazones in moderate to excellent yields under very mild conditions. Mechanistic investigation based on 31P NMR tracking experiments unveils that the reaction is initiated with the in situ formation of the modified Huisgen zwitterions from arylazocarboxylates and PPh3 and proceeds via a nitrogen to nitrogen ester group migration process. This study also represents the first exploration of the reactivity patterns of the modified Huisgen zwitterions derived from arylazocarboxylates toward electrophiles such as 1,2-dicarbonyl compounds.
一种膦介导的 1,2-二羰基化合物（如芳基甲酰基、α-二酮和色酮）与芳基偶氮羧酸酯的脱氧缩合反应已经被开发出来，用于在非常温和的条件下以中等至优异的产率轻松合成 N-芳基-N-酰基腙。基于 31P NMR 跟踪实验的机理研究表明，反应是由芳基偶氮羧酸酯和 PPh3原位形成的改良的Huisgen 两性离子引发的，并通过氮到氮酯基迁移过程进行。这项研究还代表了对由芳基偶氮羧酸酯衍生的改良 Huisgen 两性离子与亲电试剂（如 1,2-二羰基化合物）之间的反应模式的首次探索。
