An effective metal-free C-H amination of N-Ts-2-alkenylanilines by using DDQ as an oxidant has been developed to afford a diverse range of substituted indoles. This protocol is operationally simple and robust, obviates the need of expensive transition-metal catalysts, and offers a broad substrate scope. A mechanism involving a radical cation generated by SET and a migratorial process via a phenonium ion intermediate is proposed.
Regioselective synthesis of benzazetines and indoles from o-alkenylanilides was achieved. The reaction of o-vinylbenzanilide with dimethyl(methylthio)sulfonium trifluoromethanesulfonate (DMTST) gave the corresponding benzazetine in 92% yield, whereas the reaction of o-vinyl-N-p-toluenesulfonylanilide gave N-tosylindoline in 77% yield. 3-Methy-N-p-tosylindole was directly synthesized by the reaction of o-isopropenyl-N-p-tosylanilide with dimethyl disulfide and methyl triflate in 85% yield.
Palladium-catalysed ligand-free reductive Heck cycloisomerisation of 1,6-en-α-chloro-enamides
作者:Yangyang Hou、Jing Ma、Hongyi Yang、Edward A. Anderson、Andy Whiting、Na Wu
DOI:10.1039/c9cc00537d
日期:——
The first example of an intramolecular hydroarylation of 1,6-en-α-chloro-enamides was achieved by a palladium-catalysed ligand-free reductive Heck cycloisomerisation with no competing Heck-cyclised by-product.
(Azido)ynamides were efficiently converted into indoloquinolines by the use of a gold catalyst. While ynamides bearing an allylsilane gave terminal alkenes, ynamides bearing a simple alkene gave cyclopropanes. This reaction proceeds through the formation of an alpha-amidino gold carbenoid.
Copper-Catalyzed Oxidative Amination and Allylic Amination of Alkenes
作者:Timothy W. Liwosz、Sherry R. Chemler
DOI:10.1002/chem.201301800
日期:2013.9.16
enamides are useful synthetic intermediates and common components of bioactive compounds. A new protocol for their direct synthesis by a net alkene CHamination and allylic amination by using catalytic CuII in the presence of MnO2 is reported. Reactions between N‐aryl sulfonamides and vinyl arenes furnish enamides, allylic amines, indoles, benzothiazine dioxides, and dibenzazepines directly and efficiently
烯胺和烯酰胺是有用的合成中间体和生物活性化合物的常见成分。报道了在 MnO 2存在下使用催化 Cu II通过净烯烃 C H 胺化和烯丙基胺化直接合成它们的新方案。 N-芳基磺酰胺和乙烯基芳烃之间的反应直接有效地生成烯酰胺、烯丙胺、吲哚、二氧化苯并噻嗪和二苯并氮杂卓。对照实验进一步表明,在没有铜盐的情况下,单独的MnO 2可以促进反应,尽管效率较低。机理探针支持氮自由基中间体的参与。该方法非常适合从 1,1-二取代乙烯基芳烃合成烯酰胺,1,1-二取代乙烯基芳烃是现有氧化胺化方案中不常见的底物。
DMSO/SOCl<sub>2</sub>-mediated C(sp<sup>2</sup>)–H amination: switchable synthesis of 3-unsubstituted indole and 3-methylthioindole derivatives
作者:Jingran Zhang、Xiaoxian Li、Xuemin Li、Haofeng Shi、Fengxia Sun、Yunfei Du
DOI:10.1039/d0cc07453e
日期:——
The reaction of 2-alkenylanilines with SOCl2 in DMSO was found to selectively afford 3-unsubstituted indoles and 3-methylthioindoles. This switchable approach was found to be temperature-dependent: at room temperature, the reaction afforded 3-unsubstituted indoles through intramolecular cyclization and elimination; while at higher temperature, the reaction gave 3-methylthioindoles via further electrophilic