The synthesis of sulfonated 4<i>H</i>-3,1-benzoxazines <i>via</i> an electro-chemical radical cascade cyclization
作者:Tian-Jun He、Wei-Qiang Zhong、Jing-Mei Huang
DOI:10.1039/c9cc09551a
日期:——
A new route for the synthesis of sulfonated 4H-3,1-benzoxazines has been accomplished by electrochemical radical cascade cyclizations of styrenyl amides with sulfonylhydrazines. This process demonstrates a wide substrate scope with diverse functional group compatibility under metal- and external oxidant-free conditions at ambient temperature.
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。
Lactamization of sp<sup>2</sup>C−H Bonds with CO<sub>2</sub>: Transition-Metal-Free and Redox-Neutral
The first direct use of carbon dioxide in the lactamization of alkenyl and heteroaryl C−H bonds to synthesize important 2‐quinolinones and polyheterocycles in moderate to excellent yields is reported. Carbon dioxide, a nontoxic, inexpensive, and readily available greenhouse gas, acts as an ideal carbonyl source. Importantly, this transition‐metal‐free and redox‐neutral process is eco‐friendly and desirable
Brønsted Acid-Catalyzed Synthesis of<i>N</i>-Arylindoles from 2-Vinylanilines and Quinones
作者:Han-Ming Zhang、Zhong-Hua Gao、Liang Yi、Song Ye
DOI:10.1002/asia.201600420
日期:2016.10.6
In the presence of a quinone, Brønstedacid‐catalyzed intramolecular C−N bond formation of o‐vinylanilines by electrophilic cyclization was developed, giving the corresponding N‐arylindoles in good to high yields. The reaction worked well for o‐vinylanilines with terminal and internal C=C double bonds.
A General, Regioselective Synthesis of 2-Alkenylanilines
作者:Michael Harmata、Mehmet Kahraman
DOI:10.1055/s-1995-3986
日期:1995.6
Reduction of selected 2,1-benzothiazines with sodium amalgam leads to the formation of 2-alkenylanilines in high yield. The benzothiazines are readily available from the reaction of N-phenyl-S-(p-tolyl)sulfonimidoyl chloride with alkynes in the presence of aluminum chloride. The sulfonimidoyl chloride is derived from aniline, and the process described herein thus constitutes a high-yielding, regioselective functionalization of aniline.