Transition‐Metal‐Free Three‐Component Radical 1,2‐Amidoalkynylation of Unactivated Alkenes
作者:Heng Jiang、Armido Studer
DOI:10.1002/chem.201805490
日期:——
A transition‐metal‐freeradical 1,2‐amidoalkynylation of unactivated alkenes is presented. α‐Amido‐oxy acids were used as amidyl radical precursors, which were oxidized by an organic photoredox catalyst (4CzlPN). The electrophilic N‐radicals chemoselectively reacted with various aliphatic alkenes and the adduct radicals were then trapped by ethynylbenziodoxolone (EBX) reagents to eventually provide
Photoinitiated Three-Component α-Perfluoroalkyl-β-heteroarylation of Unactivated Alkenes via Electron Catalysis
作者:Danqing Zheng、Armido Studer
DOI:10.1021/acs.orglett.8b03849
日期:2019.1.4
This three-component radical cascade reaction allows an efficient synthesis of a range of perfluoroalkyl containing quinoxalin-2(1H)-one derivatives in moderate to excellent yields under mild conditions. Reactions proceed via acidic aminylradicals that are readily deprotonated to give the corresponding radical anions able to sustain the radical chain as single electrontransfer reducing reagents. Hence
提出了可见光引发的各种烯烃与全氟烷基碘和喹喔啉-2(1 H )-酮的α-全氟烷基-β-杂芳基化反应。这种三组分自由基级联反应可以在温和条件下以中等至优异的产率有效合成一系列含有全氟烷基的喹喔啉-2(1H ) -酮衍生物。反应通过酸性氨基自由基进行,该酸性氨基自由基很容易去质子化,得到相应的自由基阴离子,能够作为单电子转移还原剂维持自由基链。因此,整个级联被归类为电子催化过程。
Radical cyclization reactions. Cyclopropane ring formation by 3-exo-cyclization of 5-phenylthio-3-pentenyl radicals
作者:Živorad Čeković、Radomir Saičić
DOI:10.1016/s0040-4039(00)98035-3
日期:1990.1
Free radicalcyclopropane ring closure was accomplished by thermal decomposition of thiohydroxamic esters of 6-phenylthio-4-hexencic acids. When the reaction was performed in the presence of acrylonitrile; an addition/cyclization/elimination process took place and the corresponding cyclopentanecarbonitriles were obtained.
hydroxylamine derivatives and heterocycles is presented. A range of heterocycles, including quinoxaline-2(1H)-ones, azauracils, chromones, and quinolones, are capable for this process, allowing the direct synthesis of valuable heteroarylethylamine derivatives. Structurally diverse reaction substrates, including drug-based scaffolds, were successfully applied, demonstrating the practicality of this method.
提出了光氧化还原催化的未活化烯烃与O -酰基羟胺衍生物和杂环的 1,2-氨基杂芳基化反应。一系列杂环化合物,包括喹喔啉-2(1 H )-酮、氮尿嘧啶、色酮和喹诺酮,都能够进行该过程,从而可以直接合成有价值的杂芳基乙胺衍生物。成功应用了结构多样的反应底物,包括基于药物的支架,证明了该方法的实用性。
Silver-Catalyzed Radical Phosphonofluorination of Unactivated Alkenes
作者:Chengwei Zhang、Zhaodong Li、Lin Zhu、Limei Yu、Zhentao Wang、Chaozhong Li
DOI:10.1021/ja408031s
日期:2013.9.25
We report herein a mild and catalytic phosphonofluorination of unactivated alkenes. With catalysis by AgNO3, the condensation of various unactivated alkenes with diethyl phosphite and Selectfluor reagent in CH2Cl2/H2O/HOAc at 40 degrees C led to the efficient synthesis of beta-fluorinated alkylphosphonates with good stereoselectivity and wide functional group compatibility. A mechanism involving silver-catalyzed oxidative generation of phosphonyl radicals and silver-assisted fluorine atom transfer is proposed.