Electrochemical oxidative radical cascade cyclization of olefinic amides and thiophenols towards the synthesis of sulfurated benzoxazines, oxazolines and iminoisobenzofurans
containing N and O are important structures in pharmaceuticals, agrochemicals and functional molecules. The synthesis of these compounds usually requires complex substrates and harsh reaction conditions. Herein, we introduce a mild and efficient electrochemical oxidative strategy to construct benzoxazines, oxazolines and iminoisobenzofurans without the requirement of a transition-metal catalyst and an
含 N 和 O 的杂环是药物、农用化学品和功能分子中的重要结构。这些化合物的合成通常需要复杂的底物和苛刻的反应条件。在此,我们引入了一种温和有效的电化学氧化策略来构建苯并恶嗪、恶唑啉和亚氨基异苯并呋喃,而无需过渡金属催化剂和外部氧化剂。在一个简单的未分开的细胞中,各种烯酰胺和苯硫酚/二硒化物反应生成 69 个硫醇化和硒化杂环的例子,产率高达 83%。此外,这种自由基级联反应为一步构建 C-S/C-Se 和 C-O 键提供了一种简便的方法。
Water-Soluble Hypervalent Iodine(III) Having an I–N Bond. A Reagent for the Synthesis of Indoles
A readily accessible and bench-stable water-soluble hypervalent iodine(III) reagent (phenyliodonio)sulfamate (PISA) with an I–N bond was synthesized, and its structure was characterized by X-ray crystallography. With PISA, various indoles were synthesized via C–H amination of 2-alkenylanilines involving an aryl migration/intramolecular cyclization cascade with excellent regioselectivity in aqueous
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.
Transition-Metal-Free Oxyfluorination of Olefinic Amides for the Synthesis of Fluorinated Heterocycles
作者:Jing-Feng Zhao、Xin-Hua Duan、Hua Yang、Li-Na Guo
DOI:10.1021/acs.joc.5b01909
日期:2015.11.6
A series of fluorinated 4H-3,1-benzoxazines and iminoisobenzofurans have been synthesized through the electrophilic fluorocyclization of olefinic amides. This methodology is highlighted by its mild conditions, wide substrate scope, and good functional group tolerance.
通过烯烃酰胺的亲电氟环化反应,合成了一系列氟化的4 H -3,1-苯并恶嗪和亚氨基异苯并呋喃。该方法具有温和的条件,广泛的底物范围和良好的官能团耐受性,从而突出了该方法。
Synthesis of Sulfonated Benzo[<i>d</i>][1,3]oxazines by Merging Photoredox Catalysis and Insertion of Sulfur Dioxide
作者:Tong Liu、Danqing Zheng、Zhenhua Li、Jie Wu
DOI:10.1002/adsc.201701187
日期:2018.3.1
N‐(2‐vinylphenyl)amides, DABCO⋅(SO2)2 and arenediazonium tetrafluoroborates for the synthesis of 4‐((arylsulfonyl)methyl)‐4H‐benzo[d][1,3]oxazines under mild conditions is reported. This synthetic approach is enabled by mergingphotoredoxcatalysis and insertion of sulfurdioxide via a radical process. The specific role of photoredoxcatalysis in this transformation is supported by mechanistic investigations and
N-(2-乙烯基苯基)酰胺,DABCO⋅(SO 2)2和苯二氮杂四氟硼酸酯的光催化反应在以下条件下合成4-((芳基磺酰基)甲基)-4- H-苯并[ d ] [1,3]恶嗪据报道情况较温和。通过自由基反应将光氧化还原催化作用与二氧化硫的插入相结合,可以实现这种合成方法。机理研究和理论计算支持了光氧化还原催化在这种转变中的特定作用。