Tandem Ullmann–Goldberg Cross-Coupling/Cyclopalladation-Reductive Elimination Reactions and Related Sequences Leading to Polyfunctionalized Benzofurans, Indoles, and Phthalanes
作者:Faiyaz Khan、Mehvish Fatima、Moheb Shirzaei、Yen Vo、Madushani Amarasiri、Martin G. Banwell、Chenxi Ma、Jas S. Ward、Michael G. Gardiner
DOI:10.1021/acs.orglett.9b02235
日期:2019.8.16
Cu[I]- and Pd[0]-based catalysts, compounds such as 1 and 7 engage in tandem Ullmann–Goldberg cross-coupling and cyclopalladation-reductive elimination reactions to givebenzofurans such as 8. Related reactions involving hetero-Michael additions of o-halogenated phenols or anilines to propiolates and the Pd[0]-catalyzed cyclization of the resulting conjugates provide, in a one-pot process, alternately
Recyclable Hypervalent-Iodine-Mediated Dehydrogenative Cyclopropanation under Metal-Free Conditions
作者:Ya-Nan Duan、Zhao Zhang、Chi Zhang
DOI:10.1021/acs.orglett.6b03209
日期:2016.12.2
developed for the synthesis of cyclopropanes from the C(sp2)–C(sp3) single bonds of β-keto esters with activated methylene compounds under metal-free conditions in the presence of 5-trimethylammonio-1,3-dioxo-1,3-dihydro-1λ5-benzo[d][1,2]iodoxol-1-ol anion (AIBX), a recyclable water-soluble hypervalentiodine(V) reagent developed by our group. This mild, efficient method has a wide substrate scope and
1,2,3,9-Tetrahydro-4<i>H</i>-carbazol-4-one and 8,9-dihydropyrido-[1,2-<i>a</i>]indol-6(7<i>H</i>)-one from 1<i>H</i>-indole-2-butanoic acid
作者:Richard A. Bunce、Baskar Nammalwar
DOI:10.1002/jhet.22
日期:2009.3
title ring systems have been developed from 1H-indole-2-butanoic acid, which was easily prepared from 2-fluoro-1-nitrobenzene in four steps. Heating 1H-indole-2-butanoic acid in toluene containing p-toluenesulfonic acid at 110°C furnished 1,2,3,9-tetrahydro-4H-carbazol-4-one in 88% yield. Heating this same acid in toluene with no added acid gave 8,9-dihydropyrido[1,2-a]indol-6(7H)-one in 90% yield. The
由1 H-吲哚-2-丁酸开发了标题环系统的有效合成方法,该方法很容易从2-氟-1-硝基苯分四个步骤。在含甲苯的溶液中加热1 H-吲哚-2-丁酸对甲苯磺酸在110℃下以88%的产率提供了1,2,3,9-四氢-4 H-咔唑-4-酮。将该相同的酸在甲苯中加热,不添加酸,以90%的产率得到8,9-二氢吡啶并[1,2 - a ]吲哚-6(7H)-一。这还可以直接以92%的收率制备四氢4 H-咔唑-4-酮通过在110°C的浓盐酸中与铁进行串联还原-环芳构化-酰化反应,合成6-(2-硝基苯基)-5-氧代己酸甲酯。这种方法在五元和七元环的闭合中的应用也很成功。J.杂环化学,(2009)。
Hypervalent Iodine(III)‐Mediated Counteranion Controlled Intramolecular Annulation of Exocyclic β‐Enaminone to Carbazolone and Imidazo[1,2‐<i>a</i>]pyridine Synthesis
作者:Dhananjay Bhattacherjee、Shankar Ram、Arvind Singh Chauhan、Yamini、Sheetal、Pralay Das
DOI:10.1002/chem.201806299
日期:2019.4.23
A highly efficient and flexible protocol for intramolecular annulation of exocyclic β‐enaminones has been disclosed for the synthesis of carbazolones and imidazo[1,2‐a]pyridines through a counter‐anion‐controlled free‐radical mechanism promoted by hypervalentiodine(III). The cooperative behavior of HTIB and AgSbF6 plays a crucial role in the intramolecular annulation process through C−C and C−N bond
为环外β-烯胺酮的分子内环化一个高效和灵活的协议已经公开了carbazolones和咪唑并[1,2的合成一个]吡啶通过高价碘促进的抗衡阴离子控制自由基机理(III) 。HTIB和AgSbF 6的协同行为在通过CC和CN键形成所需的分子内环化过程中起着至关重要的作用。机械学的见解表明,系统中涉及的两个竞争性反应是由抗衡阴离子的性质决定的,抗衡阴离子的性质决定了最终产物的形成。制备并分离了各种咔唑酮和咪唑并[1,2- a ]吡啶分子,收率良好至极佳。
An Easy Access to Carbazolones and 2,3-Disubstituted Indoles
作者:Donala Janreddy、Veerababurao Kavala、J. W. John Bosco、Chun-Wei Kuo、Ching-Fa Yao
DOI:10.1002/ejoc.201001357
日期:2011.4
Synthesis of carbazol-4-ones, 3,4-dihydrocyclopental-indol-1-one, and indole derivatives by a Fe/AcOH-mediated intramolecular reductive N-heteroannulation of 3-hydroxy-2-(2-nitrophenyl)enones is demonstrated. The same protocol has been extended to access indolocarbazolone and indoloquinolone derivatives.