Novel intramolecular cycloaddition reactions of arylamino-substituted Fischer chromium carbenes
摘要:
Thermal reaction of N-arylamino-substituted Fischer chromium carbenes having a pendant 2-(1-alkenyl)substituent on the benzene ring affords either substituted indoles or quinolines, depending on starting material, via an intramolecular [2 + 2] cycloaddition forming a metallacyclobutane followed by metathesis to give indoles or beta-elimination to give quinolines.
作者:Xiao-Shan Ning、Xin Liang、Kang-Fei Hu、Chuan-Zhi Yao、Jian-Ping Qu、Yan-Biao Kang
DOI:10.1002/adsc.201701512
日期:2018.4.17
A Pd‐tBuONO co‐catalyzed scalable and practical synthesis of indoles with molecular oxygen as terminal oxidant is developed. Either terminal or internal 2‐vinylanilines could be smoothly converted to desired indoles under one general condition. This method has been evaluated in the large scale synthesis of indomethacin and a potential anti‐breast cancer drug candidate 1.
New entries to 2(1H)-quinolinones and 2H-1-benzazepin-2-ones by acid-catalyzed olefin cyclization of N-(o-(alk-1-enyl)phenyl)-2-(methylsulfinyl)acetamides.
Treatment of N-[o-(alk-1-enyl)phenyl]-2-(methylsulfinyl)acetamides with trifluoroacetic anhydride gave 2(1H)-quinolinones or 2H-1-benzazepin-2-ones, depending upon the position of the substituents on the alkene double bond.
Exploiting Iminoquinones as Electrophilic at Nitrogen “N+” Synthons for C–N Bond Construction
作者:Luis M. Mori-Quiroz、Chelsea G. Comadoll、Jonathan E. Super、Michael D. Clift
DOI:10.1021/acs.orglett.1c00867
日期:2021.9.17
New methods for C–N bond construction exploiting the N-centered electrophilic character of iminoquinones are reported. Iminoquinones, generated in situ via the condensation of o-vinylanilines with benzoquinones, undergo acid-catalyzed cyclization to afford N-arylindoles in excellent yields. Under similar reaction conditions, homoallylic amines react analogously to afford N-arylpyrroles. Additionally
报道了利用亚氨基醌的 N 中心亲电特性构建 C-N 键的新方法。通过邻乙烯基苯胺与苯醌缩合原位生成的亚氨基醌经过酸催化环化以优异的产率得到N-芳基吲哚。在类似的反应条件下,高烯丙基胺类似地反应得到N-芳基吡咯。此外,有机金属亲核试剂显示出添加到N-烷基亚氨基醌的氮原子上以提供胺产物。最后,亚氨基醌被证明是铜催化加氢胺化反应的亲电试剂。
Sequential <i>N</i>-Acylamide Methylenation−Enamide Ring-Closing Metathesis: Construction of Benzo-Fused Nitrogen Heterocycles
catalyst give access to indoles, 1,4-dihydroquinolines, and 1,2-dihydroisoquinolines, respectively. This sequential protocol also allows the synthesis of dihydrobenzoazepines, although the ring-closingmetathesis (RCM) step is complicated by the alkene isomerization processes. From certain substrates, the direct annulation is observed in the titanium-mediated step, which is likely to occur through an