Synthesis of Bicyclo[4.1.0]tetrahydropyridazines by a Sequential [4 + 2] and [1 + 2] Annulation Reaction of Azoalkenes and Crotonate-Derived Sulfur Ylides
作者:Wenhao Yin、Ling Fang、Zhiyong Wang、Fang Gao、Zhefeng Li、Zhiyong Wang
DOI:10.1021/acs.orglett.9b02661
日期:2019.9.20
The base-induced unprecedented tandem [4 + 2] and [1 + 2] annulation reaction of in situ formed 1,2-diaza-1,3-dienes and crotonate-derived sulfur ylides is reported. This protocol provides a novel and practical method for the synthesis of cyclopropane-fused tetrahydropyridazines with a quaternary carbon center in synthetically useful yield. In this tandem reaction, three new bonds were formed in one
An unprecedented [4+3] cycloaddition of in situ generated azoalkenes with C,N-cyclicazomethineimines has been developed without the use of any catalyst, providing an efficient and mild approach to synthesise highly functionalized 1,2,4,5-tetrazepine derivatives in high yields (76-92%).
Construction of 2,3,4,5-tetrahydro-1,2,4-triazines via [4 + 2] cycloaddition of α-halogeno hydrazones to imines
作者:Hong-Wu Zhao、Hai-Liang Pang、Yu-Di Zhao、Yue-Yang Liu、Li-Jiao Zhao、Xiao-Qin Chen、Xiu-Qing Song、Ning-Ning Feng、Juan Du
DOI:10.1039/c6ra27767e
日期:——
In the presence of sodium carbonate, the [4 + 2] cycloaddition of α-halogeno hydrazones to imines proceeded readily, and furnished 2,3,4,5-tetrahydro-1,2,4-triazines in moderate to high chemical yields.
Base-induced inverse-electron-demand aza-Diels-Alder reaction of azoalkenes and 1,3,5-triazinanes: Facile approaches to tetrahydro-1,2,4-triazines
作者:Chaofan Wang、Ling Fang、Zhiyong Wang
DOI:10.1016/j.tetlet.2021.153303
日期:2021.8
The base-induced an inverse-electron-demand aza-Diels-Alder reaction of in situ formed 1,2-diaza-1,3-dienes with formaldimines is reported. This protocol features cycloaddition of two in situ generated reactive intermediates and provides a reliable and practical method for the synthesis of tetrahydro-1,2,4-triazine derivatives in synthetically useful yields.
In the presence of sodium carbonate, the [4+3] cycloadditions of α‐halogeno hydrazones with nitrones were performed efficiently, and affording 2,3,4,7‐tetrahydro‐1,2,4,5‐oxatriazepines in moderate to high yields.