- DUAL TYPE OF REACTIVITY OF 1,2-DISUBSTITUTED DIHYDRO-N-HETEROAROMATIC SYSTEMS. 11. AROMATIZATION OF N-SULFONYL-1,2-DIHYDROQUINOLINES AND ISOQUINOLINES CONTAINING AN α-INDOLYL OR PYRROLYL SUBSTITUENT
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When N-sulfonyl-1,2-dihydroquinolines and isoquinolines, containing an indolyl or pyrrolyl substituent at the α-position, react with trityl perchlorate, this substituent is split off, and N-sulfonyl quinolinium and isoquinolinium cations and tritylindole or tritylpyrrole are formed.A similar reaction with 2,2,6,6-tetramethyl-1-oxopiperidinium perchlorate proceeds with splitting of hydrogen or retention of the α-substituent, which leads to the corresponding α-substituted N-sulfonylquinolinium and isoquinolinium cations.
- Chmilenko, T. S.,Nezdiiminoga, T. N.,Sidorenko, L. M.,Sheinkman, A. K.
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- A Sc(OTf)3 catalyzed dehydrogenative reaction of electron-rich (hetero)aryl nucleophiles with 9-aryl-fluoren-9-ols
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A highly efficient dehydrogenative reaction of a series of nucleophiles with 9-aryl-fluoren-9-ols has been realized by using only 2 mol% of Sc(OTf)3 as a catalyst. The corresponding indole-containing 9,9-diarylfluorenes were obtained in up to 99% yield as well as other electron-rich (hetero)arene adducts. The protocol exhibits high selectivity, mild reaction conditions and good substrate compatibility (32 examples). This protocol is further highlighted by its applications in the construction of potential electroluminescent materials.
- Zhou, Chen,Hu, Chen,Hong, Gang,He, Yuchen,Tang, Zhicong,Wang, Limin
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supporting information
p. 9615 - 9619
(2019/11/20)
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- Phosphomolybdic acid as a bifunctional catalyst for Friedel–Crafts type dehydrative coupling reaction
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Phosphomolybdic acid (H3PMo12O40) was found to be a bifunctional catalyst for C─C bond formation via the dehydrative reaction of diarylmethanols with various nucleophiles, including 2-naphthols, indoles, benzofuran and ben
- Yang, Guo-Ping,Dilixiati, Dilireba,Yang, Tao,Liu, Dong,Yu, Bing,Hu, Chang-Wen
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- Asymmetric Latent Carbocation Catalysis with Chiral Trityl Phosphate
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Stable carbocations such as tritylium ions have been widely explored as organic Lewis acid catalysts and reagents in organic synthesis. However, achieving asymmetric carbocation catalysis remains elusive ever since they were first identified over one century ago. The challenges mainly come from their limited compatibility, scarcity of chiral carbocations, as well as the extremely low barrier to racemization of chiral carbenium ions. We reported here a latent concept for asymmetric carbocation catalysis. In this strategy, chiral trityl phosphate is employed as the carbocation precursor, which undergoes facile ionic dissociation upon mild external stimulation (e.g., acid, H-bonding, polar substrates) to form a catalytically active chiral ion pair for substrate activation and chiral induction. The latent strategy provides a solution for the long sought-after asymmetric carbocation catalysis as illustrated in three different enantioselective transformations.
- Lv, Jian,Zhang, Qichao,Zhong, Xingren,Luo, Sanzhong
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p. 15576 - 15583
(2015/12/26)
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- Mild and efficient iodine-catalyzed direct substitution of hydroxy group of alcohols with c- and n-nucleophiles
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A mild and efficient iodine-catalyzed direct substitution of hydroxy group of allylic, progargylic and other alcohols with various C- and N-nucleophiles was described in this contribution. C-C and C-N bond formations could be readily achieved by non-metal
- Liu, Zhe,Wang, Dong,Chen, Yongjun
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experimental part
p. 73 - 80
(2012/04/23)
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- Organocatalyzed Friedel-Crafts arylation of benzylic alcohols
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Electron-rich aromatic and heteroaromatic rings are functionalized directly with a variety of benzylic alcohols under mild conditions. The reaction is catalyzed by commercially available pentafluorophenylboronic acid, which is stable under ambient conditions and recoverable. The reaction itself is highly atom economical and produces water as the only byproduct. A Friedel-Crafts mechanism is proposed.
- McCubbin, J. Adam,Krokhin, Oleg V.
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supporting information; experimental part
p. 2447 - 2449
(2010/07/04)
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- Nitrosation of derivatives of hydrazines, IX: Novel oxidative C-N-coupling of indazoles and benzotriazoles with cyclohepatriene, di- and triphenylmethane derivatives
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In the presence of 2,3-dichloro-5,6-dicyano-benzoquinone (DDQ) indazoles and benzotriazoles react with compounds forming stabilized carbenium ions like cycloheptatriene, di- and triphenylmethane, fluorene, xanthene and thioxanthene, yielding C-N-coupled products.
- Hanefeld,Hunz
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p. 323 - 329
(2007/10/02)
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- DUAL REACTIVITY OF 1,2-DISUBSTITUTED DIHYDRO-N-HETEROAROMATIC SYSTEMS. 8. AROMATIZATION OF N-ACYL PARTLY HYDROGENATED PYRAZINE AND QUINOXALINE DERIVATIVES
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N-mono- and N,N-diacyl 2,3-diindolyl-substituted 1,2-dihydro- and 1,2,3,4-tetrahydropyrazines and quinoxalines were aromatized with triphenylmethyl perchlorate and 2,2,6,6-tetramethyl-1-oxo-piperidinium perchlorate.The hitherto unknown N-acylquinoxalinium perchlorates were obtained.
- Lopatinskaya, Kh. Ya.,Skorobogatova, Z. M.,Sheinkman, A. K.,Zaritovskaya, T. A.
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p. 675 - 679
(2007/10/02)
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- THE DUAL REACTIVITY OF 1,2-DISUBSTITUED DIHYDRO-N-HETEROAROMATIC SYSTEMS. 5. A CASE OF AN UNUSUALLY EASY HETEROLYSIS OF THE INTERNUCLEAR BOND IN 2-(INDOL-3-YL)-1-METHYL-1,2-DIHYDROQUINOLINE AND ITS ANALOGS.
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The reaction of the 1-methylquinolinium cation with the indole anion has given a crystalline adduct of saltlike structure forming an ion pair in polar solvents and 2-(indol-3-yl)-1-methyl-1,2-dihydroquinoline in nonpolar solvents.
- Sheinkman A. K.,Chmilenko T. S.,Nezdiiminoga T. N.
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p. 991 - 996
(2007/10/02)
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