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.
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
Addition of malonic esters to azoalkenes generated in situ from α-bromo- and α-chlorohydrazones
作者:Aleksandr O. Kokuev、Sema L. Ioffe、Alexey Yu. Sukhorukov
DOI:10.1016/j.tetlet.2021.153414
日期:2021.10
Michael addition of malonicesters to azoalkenes generated in situ from α-bromo- and α-chlorohydrazones was accomplished. Both aliphatic and aromatic substrates bearing different functional groups are tolerated. The use of a strong base (sodium hydride) for generation of azoalkenes and deprotonation of malonate was found to be essential for a successful coupling. Synthetic potential of the obtained
Synthesis of fused indoline heterocycles via dearomatization of indoles with α-bromohydrazones: a systematic study on the substrates
作者:Wen-Bin Cao、Xiao-Ping Xu、Shun-Jun Ji
DOI:10.1039/c6ob02362b
日期:——
An efficient metal-free dearomatization of indoles with α-bromohydrazones is reported. Various fused indoline heterocycles, which are potentially biologically active, were achieved in good yields (up to 94%) under mild conditions. A systematic study on electronic- and steric effects of substrate and reagents revealed that they have great influence upon the reaction. Based on this, the scope of indoles
Inverse Electron-Demand Aza-Diels–Alder Reaction of α,β-Unsaturated Thioesters with In Situ-Generated 1,2-Diaza-1,3-dienes for the Synthesis of 1,3,4-Thiadiazines
electron-demand aza-Diels–Alder reaction of α,β-unsaturated thioesters with 1,2-diaza-1,3-dienes generated in situ from α-halogeno hydrazones was developed. With α,β-unsaturated thioesters as C═S dienophiles, the developed protocol enables the formation of diverse 3,6-dihydro-2H-1,3,4-thiadiazine derivatives in excellent yields. In the presence of lithiumaluminumhydride, 3,6-dihydro-2H-1,3,4-thiadiazine
开发了α,β-不饱和硫酯与 α-卤代腙原位生成的 1,2-二氮杂-1,3-二烯的高度区域选择性逆电子需求氮杂-狄尔斯-阿尔德反应。以 α,β-不饱和硫酯作为 C=S 亲双烯体,所开发的方案能够以优异的收率形成多种 3,6-二氢-2 H -1,3,4-噻二嗪衍生物。在氢化铝锂的存在下,3,6-二氢-2 H -1,3,4-噻二嗪衍生物可以进一步转化为5,6-二氢-4 H -1,3,4-噻二嗪,收率良好。