- Synthesis of functionalized indoles via palladium-catalyzed cyclization of N-(2-allylphenyl) benzamide: A method for synthesis of indomethacin precursor
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We developed an efficient method for synthesis of substituted N-benzoylindole via Pd(II)-catalyzed C-H functionalization of substituted N-(2-allylphenyl)benzamide. The reaction showed a broad substrate scope (including N-acetyl and N-Ts substrates) and substituted indoles were obtained in good to excellent yields. The most distinctive feature of this method lies in the high selectivity for N-benzoylindole over benzoxazine, and this is the first example of Pd(II)-catalyzed synthesis of substituted N-benzoylindole. Notably, this new method was applied for the synthesis of key intermediate of indomethacin.
- Chang, Zhe,Dong, Zheng,Ma, Tong,Zhang, Yu,Zhao, Depeng,Zhao, Heng
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- Room Temperature Iron-Catalyzed Transfer Hydrogenation and Regioselective Deuteration of Carbon-Carbon Double Bonds
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An iron catalyst has been developed for the transfer hydrogenation of carbon-carbon multiple bonds. Using a well-defined β-diketiminate iron(II) precatalyst, a sacrificial amine and a borane, even simple, unactivated alkenes such as 1-hexene undergo hydrogenation within 1 h at room temperature. Tuning the reagent stoichiometry allows for semi- and complete hydrogenation of terminal alkynes. It is also possible to hydrogenate aminoalkenes and aminoalkynes without poisoning the catalyst through competitive amine ligation. Furthermore, by exploiting the separate protic and hydridic nature of the reagents, it is possible to regioselectively prepare monoisotopically labeled products. DFT calculations define a mechanism for the transfer hydrogenation of propene with nBuNH2 and HBpin that involves the initial formation of an iron(II)-hydride active species, 1,2-insertion of propene, and rate-limiting protonolysis of the resultant alkyl by the amine N-H bond. This mechanism is fully consistent with the selective deuteration studies, although the calculations also highlight alkene hydroboration and amine-borane dehydrocoupling as competitive processes. This was resolved by reassessing the nature of the active transfer hydrogenation agent: experimentally, a gel is observed in catalysis, and calculations suggest this can be formulated as an oligomeric species comprising H-bonded amine-borane adducts. Gel formation serves to reduce the effective concentrations of free HBpin and nBuNH2 and so disfavors both hydroboration and dehydrocoupling while allowing alkene migratory insertion (and hence transfer hydrogenation) to dominate.
- Espinal-Viguri, Maialen,Neale, Samuel E.,Coles, Nathan T.,MacGregor, Stuart A.,Webster, Ruth L.
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p. 572 - 582
(2019/01/08)
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- Synthesis of Benzofuran and Indole Derivatives Catalyzed by Palladium on Carbon
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Benzofurans and indoles are key moieties in many natural products and pharmaceuticals. Herein, we describe a cheap and easy-to-execute strategy for the synthesis of benzofurans and indoles, employing Pd/C as the promoter. A variety of substituted allyl-anilines and allyl-phenols were converted into the desired products in good to excellent yields. Recycling of Pd/C was possible up to five cycles, keeping similar levels of reactivity.
- Savvidou, Anatoli,IoannisTzaras, Dimitrios,Koutoulogenis, Giorgos S.,Theodorou, Alexis,Kokotos, Christoforos G.
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p. 3890 - 3897
(2019/06/27)
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- One-pot Construction of Difluorinated Pyrrolizidine and Indolizidine Scaffolds via Copper-Catalyzed Radical Cascade Annulation
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A convenient approach to the synthesis of diverse difluorinated nitrogen-containing polycycles via a copper-catalyzed radical cascade annulation of amine-containing olefins and ethyl bromodifluoroacetate was developed. Three new bonds, including a Csp3 ?CF2 and two C?N bonds, are forged simultaneously in this strategy. Through this strategy, a series of difluorinated pyrrolizidine and indolizidine derivatives have been conveniently synthesized in good yields. (Figure presented.).
- Wang, Xiaoyang,Li, Miao,Yang, Yanyan,Guo, Minjie,Tang, Xiangyang,Wang, Guangwei
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p. 2151 - 2156
(2018/04/26)
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- Green Organocatalytic Synthesis of Indolines and Pyrrolidines from Alkenes
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Employing a green and efficient 2,2,2-trifluoroacetophenone-catalyzed oxidation of alkenes, which utilizes H2O2 as the green oxidant, a novel and sustainable synthesis of indolines and pyrrolidines was developed. This constitutes a cheap, general and environmentally-friendly protocol for the synthesis of substituted nitrogen-containing heterocycles. A variety of substitution patterns, both aromatic and aliphatic moieties, are well tolerated leading to the desired nitrogen heterocycles in good to excellent yields. (Figure presented.).
- Theodorou, Alexis,Kokotos, Christoforos G.
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p. 1577 - 1581
(2017/05/05)
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- Palladium-Catalyzed Aerobic Intramolecular Aminoacetoxylation of Alkenes Enabled by Catalytic Nitrate
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A mild aerobic intramolecular aminoacetoxylation method for the synthesis of pyrrolidine and indoline derivatives was achieved using molecular oxygen as the oxidant. A catalytic NOx species acts as an electron transfer mediator to access a high-valent palladium intermediate as the presumed active oxidant.
- Li, Jiaming,Grubbs, Robert H.,Stoltz, Brian M.
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p. 5449 - 5451
(2016/11/17)
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- Copper-catalyzed radical cascade cyclization for the synthesis of phosphorated indolines
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A novel and convenient approach to the synthesis of various phosphorated indolines via a copper-catalyzed radical cascade cyclization reaction has been developed. The reaction employs cheap copper as the catalyst and K2S2O8 as the oxidant under mild conditions. Various alkenes and P-radical precursors are compatible with this transformation. Preliminary mechanistic studies reveal that the addition of the P-radical may initiate the reaction, and then oxidative cyclization may be achieved to afford the desired product. This journal is
- Zhang, Hong-Yu,Mao, Liu-Liang,Yang, Bin,Yang, Shang-Dong
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p. 4101 - 4104
(2015/03/30)
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- M-CPBA-Mediated Intramolecular Aminohydroxylation of N-Sulfonyl Aminoalkenes to Synthesize β-Hydroxyl Cyclic Amines
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A variety of structurally diverse N-sulfonyl-protected aminoalkenes readily reacted with m-CPBA to produce a series of β-hydroxyl cyclic amines in high yields through intramolecular aminohydroxylation. This metal-free and easy-to-handle synthetic methodol
- Yin, Yan,Zhou, Hong,Sun, Guofeng,Liu, Xichen
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p. 1337 - 1345
(2015/10/06)
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- Efficient copper-catalyzed direct intramolecular aminotrifluoromethylation of unactivated alkenes with diverse nitrogen-based nucleophiles
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A mild, convenient, and step-economical intramolecular aminotrifluoromethylation of unactivated alkenes with a variety of electronically distinct, nitrogen-based nucleophiles in the presence of a simple copper salt catalyst, in the absence of extra ligand
- Lin, Jin-Shun,Xiong, Ya-Ping,Ma, Can-Liang,Zhao, Li-Jiao,Tan, Bin,Liu, Xin-Yuan
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p. 1332 - 1340
(2014/04/03)
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- Palladium-catalyzed selective aminoamidation and aminocyanation of alkenes using isonitrile as amide and cyanide sources
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A mild and efficient palladium-catalyzed intermolecular aminoamidation and aminocyanation reaction of alkenes with a broad substrate scope has been developed. This cyclization process provides a valuable synthetic tool for obtaining substituted indolines, tetrahydroisoquinolines and pyrrolidines in good to excellent yields. This journal is
- Jiang, Huanfeng,Gao, Hanling,Liu, Bifu,Wu, Wanqing
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p. 15348 - 15351
(2015/01/08)
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- Catalytic enantioselective alkene aminohalogenation/cyclization involving atom transfer
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Problem solved: The title reaction was used for the synthesis of chiral 2-bromo, chloro, and iodomethyl indolines and 2-iodomethyl pyrrolidines (see scheme). Stereocenter formation is believed to occur by enantioselective cis aminocupration and C-X bond formation is believed to occur by atom transfer. The ultility of the products as versatile synthetic intermediates was demonstrated, as was a radical cascade cyclization sequence. Copyright
- Bovino, Michael T.,Chemler, Sherry R.
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p. 3923 - 3927
(2012/05/20)
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- A new entry to the phenanthridine ring system
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A new synthesis of phenanthridine derivatives having three-point diversity has been developed based on the sequential application of three-atom economic processes viz. aza-Claisen rearrangement, ring-closing enyne metathesis and Diels-Alder reaction as key steps. An unexpected isomerisation was observed during aza-Claisen rearrangement of N-allylanilines which may open up new opportunities in heterocyclic synthesis.
- Mondal, Poulomi,Thander, Latibuddin,Chattopadhyay, Shital K.
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p. 1328 - 1331
(2012/04/04)
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- Synthesis of nitrogen-containing heterocycles via ring-closing ene-ene and ene-yne metathesis reactions: An easy access to 1- and 2-benzazepine scaffolds and five- and six-membered lactams
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Novel regioselective ring closing ene-yne metathesis provided an efficient access to different substituted 1-benzazepine scaffolds. The reported synthetic approach could also be used as a powerful tool for the selective formation of a highly functionaliza
- Benedetti, Erica,Lomazzi, Michela,Tibiletti, Francesco,Palmisano, Giovanni,Penoni, Andrea,Goddard, Jean-Philippe,Fensterbank, Louis,Malacria, Max
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supporting information
p. 3523 - 3533,11
(2012/12/12)
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- Palladium(II)-catalyzed oxidative cascade cyclization reactions of anilides and anilines: Scope and mechanistic investigations
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With Pd(OAc)2/pyridine as the catalyst system and molecular oxygen as a green oxidant, acrylanilides and N-allylanilines undergo oxidative cascade cyclization to form heterocyclic rings in high yields. This methodology is applicable to acrylani
- Yip, Kai-Tai,Yang, Dan
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supporting information; scheme or table
p. 2166 - 2175
(2011/10/12)
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- Synthesis, structural elucidation and in vitro antiparasitic activity against Trypanosoma cruzi and Leishmania chagasi parasites of novel tetrahydro-1-benzazepine derivatives
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Forty six new 1,4-epoxy-2-exo-aryl- and cis-2-aryl-4-hydroxytetrahydro-1- benzazepine derivatives were synthesized and fully characterized. All compounds were tested in vitro against both Trypanosoma cruzi and Leishmania chagasi parasites and also for cyt
- Gomez-Ayala, Sandra,Castrillon, Julian A.,Palma, Alirio,Leal, Sandra M.,Escobar, Patricia,Bahsas, Ali
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scheme or table
p. 4721 - 4739
(2010/08/22)
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- Highly stereoselective 7-endo-trig /ring contraction cascade to construct pyrrolo[1,2- a ]quinoline derivatives
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With the cooperation of Cram's phenonium ion, a novel cascade reaction was illustrated to construct pyrrolo[1,2-a]quinolines as a sole diastereoisomer in good to excellent yields. Preliminary mechanistic studies revealed that the γ-lactam ring and electron-rich arene are important driving forces for ring contraction.
- Li, Xinyu,Li, Cheng,Zhang, Wenjing,Lu, Xiang,Han, Shiqing,Hong, Ran
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supporting information; experimental part
p. 1696 - 1699
(2010/09/05)
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- Synthesis of highly substituted dibenzoazocine derivatives by the aza-Claisen rearrangement and intramolecular Heck reaction via 8-exo-trig mode of cyclization
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The synthesis of highly substituted dibenzo-azocine systems is still lacking. An efficient synthetic protocol utilizing the sequential aromatic aza-Claisen rearrangement followed by the implementation of the intramolecular Heck reaction as a key step has been developed for the synthesis of various dibenzo-azocine derivatives of biological relevance.
- Majumdar,Chattopadhyay, Buddhadeb,Samanta, Srikanta
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scheme or table
p. 3178 - 3181
(2009/08/07)
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- Pd(II)-catalyzed enantioselective oxidative tandem cyclization reactions. Synthesis of indolines through C-N and C-C bond formation
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We have developed an efficient Pd(II)-catalyzed enantioselective oxidative tandem cyclization strategy using molecular oxygen as a green oxidant for the double 5-exo-trig cyclizations of N-(2-allylaryl) amides to afford a variety of indolines in good yiel
- Yip, Kai-Tai,Yang, Min,Law, Ka-Lun,Zhu, Nian-Yong,Yang, Dan
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p. 3130 - 3131
(2007/10/03)
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- Novel strategies for the solid phase synthesis of substituted indolines and indoles
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Using a polymer-bound selenenyl bromide resin, o-allyl and o-prenyl anilines were cycloaded to afford a series of solid-supported indoline and indole scaffolds. These scaffolds were then functionalized and cleaved via four distinct methods, namely traceless reduction, radical cyclization, radical rearrangement, and oxidative elimination, to afford 2-methyl indolines, polycyclic indolines, 2-methyl indoles, and 2-propenyl indolines, respectively. A number of small combinatorial libraries of compounds reminiscent of certain designed ligands of biological interest were constructed demonstrating the potential utility of the developed methodology to chemical biology studies and the drug discovery process.
- Nicolaou,Roecker,Hughes, Robert,Van Summeren, Ruben,Pfefferkorn, Jeffrey A.,Winssinger, Nicolas
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p. 465 - 476
(2007/10/03)
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