480390-47-4Relevant academic research and scientific papers
Photoredox catalysis on unactivated substrates with strongly reducing iridium photosensitizers
Shon, Jong-Hwa,Kim, Dooyoung,Rathnayake, Manjula D.,Sittel, Steven,Weaver, Jimmie,Teets, Thomas S.
, p. 4069 - 4078 (2021/04/06)
Photoredox catalysis has emerged as a powerful strategy in synthetic organic chemistry, but substrates that are difficult to reduce either require complex reaction conditions or are not amenable at all to photoredox transformations. In this work, we show that strong bis-cyclometalated iridium photoreductants with electron-rich β-diketiminate (NacNac) ancillary ligands enable high-yielding photoredox transformations of challenging substrates with very simple reaction conditions that require only a single sacrificial reagent. Using blue or green visible-light activation we demonstrate a variety of reactions, which include hydrodehalogenation, cyclization, intramolecular radical addition, and prenylationviaradical-mediated pathways, with optimized conditions that only require the photocatalyst and a sacrificial reductant/hydrogen atom donor. Many of these reactions involve organobromide and organochloride substrates which in the past have had limited utility in photoredox catalysis. This work paves the way for the continued expansion of the substrate scope in photoredox catalysis.
Biaryl Cross-Coupling Enabled by Photo-Induced Electron Transfer
Hayashi, Hirohito,Wang, Bin,Wu, Xiangyang,Teo, Shi Jie,Kaga, Atsushi,Watanabe, Kohei,Takita, Ryo,Yeow, Edwin K. L.,Chiba, Shunsuke
supporting information, p. 2223 - 2231 (2020/04/30)
We report a protocol for aryl cross-coupling of electron-deficient aryl halides with electron-rich (hetero)arenes that is driven solely by violet light. This process takes advantage of formation of photo-excited state of electron-deficient aryl halides, that are reduced by electron-rich (hetero)arenes to form a pair of aryl anion and cation radicals. The resulting aryl anion radicals of aryl halides undergo mesolysis of the carbon-halogen bond to generate aryl radicals, that are coupled most likely with aryl cation radicals to afford functionalized biaryls. (Figure presented.).
Generation of Aryl Radicals from Aryl Halides: Rongalite-Promoted Transition-Metal-Free Arylation
Yu, Fazhi,Mao, Runyu,Yu, Mingcheng,Gu, Xianfeng,Wang, Yonghui
, p. 9946 - 9956 (2019/09/04)
A new and practical method for the generation of aryl radicals from aryl halides is reported. Rongalite as a novel precursor of super electron donors was used to initiate a series of electron-catalyzed reactions under mild conditions. These transition-metal-free radical chain reactions enable the efficient formation of C-C, C-S, and C-P bonds through homolytic aromatic substitution or SRN1 reactions. Moreover, the synthesis of antipsychotic drug Quetiapine was performed on gram scale through the described method. This protocol demonstrated its potential as a promising arylation method in organic synthesis.
A general copper-based photoredox catalyst for organic synthesis: Scope, application in natural product synthesis and mechanistic insights
Deldaele, Christopher,Michelet, Bastien,Baguia, Hajar,Kajouj, Sofia,Romero, Eugenie,Moucheron, Cecile,Evano, Gwilherm
, p. 621 - 629 (2018/10/04)
Organic transformations can broadly be classified into four categories including cationic, anionic, pericyclic and radical reactions. While the last category has been known for decades to provide remarkably efficient synthetic pathways, it has long been hampered by the need for toxic reagents, which considerably limited its impact on chemical synthesis. This situation has come to an end with the introduction of new concepts for the generation of radical species, photoredox catalysis – which simply relies on the use of a catalyst that can be activated upon visible light irradiation – certainly being the most efficient one. The state-of-the-art catalysts mostly rely on the use of ruthenium and iridium complexes and organic dyes, which still considerably limits their broad implementation in chemical processes: alternative readily available catalysts based on inexpensive, environmentally benign base metals are therefore strongly needed. Furthermore, expanding the toolbox of methods based on photoredox catalysis will facilitate the discovery of new light-mediated transformations. This article details the use of a simple copper complex which, upon activation with blue light, can initiate a broad range of radical reactions.
A General Copper Catalyst for Photoredox Transformations of Organic Halides
Michelet, Bastien,Deldaele, Christopher,Kajouj, Sofia,Moucheron, Cécile,Evano, Gwilherm
supporting information, p. 3576 - 3579 (2017/07/17)
A broadly applicable copper catalyst for photoredox transformations of organic halides is reported. Upon visible light irradiation in the presence of catalytic amounts of [(DPEphos)(bcp)Cu]PF6 and an amine, a range of unactivated aryl and alkyl halides were shown to be smoothly activated through a rare Cu(I)/Cu(I)?/Cu(0) catalytic cycle. This complex efficiently catalyzes a series of radical processes, including reductions, cyclizations, and direct arylation of arenes.
Direct C–H Arylation of Heteroarenes with Aryl Chlorides by Using an Abnormal N-Heterocyclic-Carbene–Palladium Catalyst
Ahmed, Jasimuddin,Sau, Samaresh Chandra,Sreejyothi,Hota, Pradip Kumar,Vardhanapu, Pavan K.,Vijaykumar, Gonela,Mandal, Swadhin K.
, p. 1004 - 1011 (2017/02/15)
Herein, we report a versatile catalytic system for the direct C–H arylation of heteroarenes with activated aryl chloride substrates. The catalyst works successfully for a variety of heteroarenes and aryl chloride coupling partners under very low catalyst-loading conditions. We have successfully performed the direct C–H arylations of 1-methylpyrrole, 1-methylindole, furan, thiophene, furfural, and N-benzyl-1,2,3-triazole with aryl chloride partners in good yields without the use of any additives. Furthermore, we used this catalytic process to develop a one-pot synthetic protocol for the muscle relaxant dantrolene on a gram scale. Additionally, the present catalytic system can be used to perform consecutive arylations in one pot.
AgONO-Assisted Direct C-H Arylation of Heteroarenes with Anilines
Gowrisankar, Saravanan,Seayad, Jayasree
supporting information, p. 12754 - 12758 (2015/03/30)
A novel copper-catalyzed C-H arylation of heteroarenes with anilines by an in situ diazonium reaction is established by using silver nitrite (AgONO) as an unconventional nitrosating reagent under acid-free conditions. It provides a complementary approach for the C-H arylation of electron-rich heteroarenes with aromatic amines affording a variety of heterobiaryls in moderate to good yields.
Palladium-catalysed direct desulfitative arylation of pyrroles using benzenesulfonyl chlorides as alternative coupling partners
Jin, Rongwei,Yuan, Kedong,Chatelain, Emmanuelle,Soul, Jean-Franois,Douceta, Henri
, p. 3831 - 3841 (2015/01/16)
The reactivity of pyrrole derivatives for palladium-catalysed desulfitative arylation has been investigated. 1-Methyl-, 1-phenyl- and 1-benzylpyrroles were successfully coupled with a variety of benzenesulfonyl chlorides using a phosphine-free catalyst. Highly regioselective arylations at carbon C2 of pyrroles were observed in all cases. A wide variety of substituents on the benzenesulfonyl derivative was tolerated. It should be noted that even bromo- and iodo-benzenesulfonyl chlorides were successfully coupled with pyrrole derivatives without cleavage of the C-Br or C-I bonds, allowing further transformations. Surprisingly, with indoles, mixtures of C2- and C3-arylation products were obtained.
β-selective C-H arylation of pyrroles leading to concise syntheses of lamellarins C and I
Ueda, Kirika,Amaike, Kazuma,Maceiczyk, Richard M.,Itami, Kenichiro,Yamaguchi, Junichiro
supporting information, p. 13226 - 13232 (2015/03/30)
The first general β-selective C-H arylation of pyrroles has been developed by using a rhodium catalyst. This C-H arylation reaction, which is retrosynthetically straightforward but results in unusual regioselectivity, could result in de novo syntheses of
Room-temperature arylation of arenes and heteroarenes with diaryliodonium salts by photoredox catalysis
Liu, Yu-Xia,Xue, Dong,Wang, Jia-Di,Zhao, Cong-Jun,Zou, Qing-Zhu,Wang, Chao,Xiao, Jianliang
supporting information, p. 507 - 513 (2013/04/10)
Aryl radicals produced by irradiation of diaryliodonium salts with visible light under the catalysis of [Ru(bpy)3]2+ undergo coupling with a wide range of arenes and heteroarenes, affording various biaryls through direct C-H arylation at room temperature. Georg Thieme Verlag Stuttgart · New York.
