- Transition-Metal-Free Synthesis of 1,2-Disubstituted Indoles
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Herein, we report a new transition-metal-free robust and cost-effective method for synthesis of 1,2-disubstituted indoles from easily available unactivated (i.e. without EWG, PPh3 or SiR3 groups) tertiary amides. Scope of synthetic applicability of the presented protocol was shown on 23 examples of 1,2-disubstituted indoles with different substitution patterns obtained in good to excellent yields. The reported method turned out to be especially effective for synthesis of N-arylated 2-CF3-indoles. Moreover, this approach can be performed in a one-pot two-step manner directly from commercially available secondary amines. Mechanistic studies showed that acyl transfer might be an important step in the course of the reaction. Viability of the presented approach for benzofurans and benzothiophenes synthesis was also discussed.
- Chesnokov, Gleb A.,Ageshina, Alexandra A.,Topchiy, Maxim A.,Nechaev, Mikhail S.,Asachenko, Andrey F.
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p. 4844 - 4854
(2019/08/01)
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- Direct Synthesis of 3-Acylindoles through Rhodium(III)-Catalyzed Annulation of N-Phenylamidines with α-Cl Ketones
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In the present study, a novel synthetic strategy to directly produce versatile 3-acylindoles through Rh(III)-catalyzed C-H activation and annulation cascade of N-phenylamidines with α-Cl ketones was developed, in which α-Cl ketones serve as unusual one-carbon (sp3) synthons. This strategy features high regioselectivity, efficiency, wide substrate tolerance, and mild reaction conditions, which further underscore its synthetic utility in drug molecule synthesis.
- Zhou, Jianhui,Li, Jian,Li, Yazhou,Wu, Chenglin,He, Guoxue,Yang, Qiaolan,Zhou, Yu,Liu, Hong
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p. 7645 - 7649
(2018/12/11)
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- Palladium-catalyzed carbonylation of indoles for synthesis of indol-3-yl aryl ketones
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A novel palladium-catalyzed carbonylation of indoles with CO and aromatic boronic acids for the synthesis of indol-3-yl aryl ketones was developed. The reaction tolerates a wide range of functional groups and gives a variety of valuable indol-3-yl aryl ketones in high yields under mild conditions. (Chemical Presented).
- Zhao, Mi-Na,Ran, Longfei,Chen, Ming,Ren, Zhi-Hui,Wang, Yao-Yu,Guan, Zheng-Hui
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p. 1210 - 1213
(2015/02/19)
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- Synthesis of 3-acylindoles by visible-light induced intramolecular oxidative cyclization of o -alkynylated N,N -dialkylamines
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A visible-light photoredox synthesis of 3-acylindoles through intramolecular oxidative cyclization of o-alkynylated N,N-dialkylamines is developed. The reaction proceeds effectively under mild reaction conditions using air as the oxidant, and only water is generated as a side product. A plausible mechanism involving the addition of α-amino alkyl radicals to alkynes, followed by C-O bond formation, is proposed.
- Zhang, Ping,Xiao, Tiebo,Xiong, Shengwei,Dong, Xichang,Zhou, Lei
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supporting information
p. 3264 - 3267
(2014/07/08)
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- Palladium-copper-cocatalyzed intramolecular oxidative coupling: An efficient and atom-economical strategy for the synthesis of 3-acylindoles
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A new and efficient catalytic approach to the synthesis of 3-acylindoles under Pd-Cu-cocatalyzed oxidative conditions is demonstrated. tert-Butyl hydroperoxide (TBHP) acts not only as the oxidant, but also as an oxygen source in the approach. The process allows quick and atom-economical assembly of 3-acylindoles from readily available starting materials and tolerates a broad range of functional groups.
- Xia, Xiao-Feng,Zhang, Lu-Lu,Song, Xian-Rong,Niu, Yan-Ning,Liu, Xue-Yuan,Liang, Yong-Min
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supporting information
p. 1410 - 1412
(2013/02/25)
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- Nucleophilic addition of grignard reagents to 3-acylindoles: Stereoselective synthesis of highly substituted indoline scaffolds
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3-Acylindoles undergo nucleophilic-type reactions with Grignard reagents to efficiently afford either cis- or trans-substituted indolines, depending on the different quenching procedures. The enolate intermediate could be trapped by aryl acyl chlorides to provide indolines bearing a quaternary carbon center with high stereoselectivity. In contrast, the use of benzyl bromide as an electrophile results in the fragmentation of the indole ring. The indoline products could be easily transformed into indoles through oxidation with DDQ in a one-pot manner.
- Wang, Lu,Shao, Yushang,Liu, Yuanhong
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p. 3978 - 3981
(2012/10/08)
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- Novel synthesis of 2-aryl and 2,3-disubstituted indoles by modified double elimination protocol
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(Chemical Equation Presented) Syntheses of 2-aryl and 2,3-substituted indoles were realized by modified double elimination protocol. Under basic conditions, vinyl sulfones derived from the reaction of 2-aminobenzyl sulfone with benzaldehydes underwent cyclization and alkylation followed by elimination of sulfinic acid to afford 2,3-substituted indoles.
- Babu, Govindarajulu,Orita, Akihiro,Otera, Junzo
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p. 4641 - 4643
(2007/10/03)
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- Dipolar Cycloaddition Reactions of (Phenylsulfonyl)alkanes and (Phenylsulfonyl)propadiene with C,N-Diphenylnitrone
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The reaction of the title nitrone with (phenylsulfonyl)alkynes 1a,b results in 3-acylindoles 6a,b via unstable 4-isoxazoline cycloadducts which evolve by fission of the N-O bond and subsequent reclosure onto the ortho position of the N-phenyl substituent.Under the same conditions, the title nitrone reacts with (phenylsulfonyl)propadiene (10) to give the isomeric benzazepinone 12 and pyrrolidone 11, both of which are presumably formed from a common, transient cycloadduct.Compound 12 changes readily through a novel pathway leading to the indole derivative 14.
- Parpani, Patrizia,Zecchi, Gaetano
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p. 1417 - 1421
(2007/10/02)
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