以K 2 S 2 O 8 -氮掺杂石墨烯的混合物为氧化剂,从芳基炔酸酯和亚硝酸盐直接得到一系列高收率的3-nitro-4-aryl-2 H -chromen-2-ones在室温下的含水介质中。还报道了该反应的合理机制。它表明该产物是通过硝基自由基加成、螺环化和酯迁移的级联反应形成的。与合成 3-nitro-4-aryl-2 H的已知方法相比-chromen-2-ones 来自芳基炔酸酯,该协议是环保、可持续、实用和节能的,并且不使用有害的硝基源。此外,这种方法中使用的氮掺杂石墨烯可以很容易地回收和重复使用至少四次而不会失去其活性。
Visible Light-Induced Decarboxylative Acylarylation of Phenyl Propiolates with α-Oxocarboxylic Acids to Coumarins Catalyzed by Hypervalent Iodine Reagents under Transition Metal-Free Conditions
作者:Shuai Yang、Hui Tan、Wangqin Ji、Xiangbiao Zhang、Pinhua Li、Lei Wang
DOI:10.1002/adsc.201600721
日期:2017.2.2
No Abstract
没有摘要
An efficient light on–off one-pot method for the synthesis of 3-styryl coumarins from aryl alkynoates
An efficientone-pot stepwise method to synthesize 3-styryl-4-arylcoumarins from simple alkynoates is demonstrated. On the basis of the control experiments, a possible mechanism involving light-driven radical cyclization and Pd-catalysed cross-coupling processes for this synthesismethod is proposed. The results of X-ray analysis and spectroscopy experiments prove that the substituent effect has a
Visible-light photoredox catalyzed cyclization of aryl alkynoates for the synthesis of trifluoromethylated coumarins
作者:Mei-jie Bu、Guo-ping Lu、Chun Cai
DOI:10.1016/j.catcom.2018.06.009
日期:2018.8
for the synthesis of coumarin derivatives via visible-lightphotoredoxcatalysis has been developed using fac-Ir(ppy)3 as the photocatalyst under mild conditions. Trifluoromethanesulfonyl chloride is utilized as the trifluoromethylation reagent, which is cheap and readily available. Aryl alkynoates are trifluoromethylated, then undergo a radical cyclization and a cascade ester migration to generate target
Synthesis of 3-sulfonyl coumarins through radical sulfonylation with disulfides under catalyst-free conditions
作者:Hexiang Ren、Ming Zhang、Ai Qin Zhang
DOI:10.1016/j.tet.2018.07.014
日期:2018.8
strategy for the synthesis of 3-sulfonyl coumarins via ipso-cyclization/1,2-ester migration from substituted phenyl 3-phenylpropiolates with disulfides and potassium persulfate as sulfonylating reagents was developed, halogen and many other electron-withdrawing or -donating functional groups are tolerated. When naphthalen-1-yl 3-phenylpropiolate was used as a starting material, a spiro compound was obtained
Selenocysteinyl electrophiles efficiently promote the formation of coumarin and quinolinone cores by 6-<i>endo-dig</i> cyclization
作者:Sindija Lapcinska、Pavel Arsenyan
DOI:10.1039/d1nj02633j
日期:——
Efficient methods have been disclosed for the construction of nitrogen and oxygen containing heterocyclic systems attached to selenocysteine or selenoglutathione. An inorganic oxidant (K2S2O8) or a mild Lewis acid (CuBr2) was employed for the generation of selanyl electrophiles that were further trapped with phenyl propiolates, methyl 2-(phenylethynyl)benzoate, N-phenyl propiolamides and 2-(phenylethynyl)benzamide
已经公开了用于构建与硒代半胱氨酸或硒代谷胱甘肽相连的含氮和氧的杂环系统的有效方法。无机氧化剂 (K 2 S 2 O 8 ) 或温和的路易斯酸 (CuBr 2 ) 用于生成硒基亲电试剂,这些亲电试剂被丙炔酸苯酯、2-(苯基乙炔基)苯甲酸甲酯、N-苯基丙炔酰胺和 2 - (苯基乙炔基)苯甲酰胺,从而提供相应的香豆素,异香豆素,喹啉-2-酮和异喹啉-2-酮通过6-内-挖环化。可见光的使用导致发散的反应性,提供三键加成产物或带有硒代半胱氨酸部分的螺环化合物。