Silver(I)‐ and Base‐Mediated formal [4+3] Cycloaddition of
<i>in Situ</i>
generated 1,2‐Diaza‐1,3‐dienes with
<i>C,N</i>
‐Cyclic Azomethine Imines: An Efficient Protocol for the Synthesis of Tetrazepine Derivatives
作者:Zefei Li、Shuaikang Li、Tianjiao Kan、Xinyue Wang、Xin Xin、Yunlei Hou、Ping Gong
DOI:10.1002/adsc.202000398
日期:2020.7.16
A silver(I)‐ and base‐mediated formal [4+3] cycloadditionreaction of in situ generated 1,2‐diaza‐1,3‐dienes with in situ formed C,N‐cyclic azomethine imines has been developed. This protocol provided an efficient method for the synthesis of biologically important 1,2,4,5‐tetrazepine derivatives with a wild substrate scope and excellent functional group tolerance in moderate to excellent yields.
Pyridinium 1,4-zwitterionic thiolates as a useful class of sulfur-containing synthons: application to the synthesis of 2,5-dihydro-1,4,5-thiadiazepines
A novel [4+3] cascade cyclization reaction of pyridinium 1,4-zwitterionic thiolates with azoalkenes derived from α-halo hydrazones in situ has been developed. This reaction was found to allow expedient access to an array of 2,5-dihydro-1,4,5-thiadiazepines. Libraries of highly functionalized sulfoxide and sulfone analogues of 2,5-dihydro-1,4,5-thiadiazepines were also obtained via selective oxidation
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.