1022-86-2Relevant academic research and scientific papers
Acid fluorides as acyl electrophiles in suzuki–miyaura coupling
Ogiwara, Yohei,Sakino, Daisuke,Sakurai, Yuka,Sakai, Norio
, p. 4324 - 4327 (2017)
The first palladium-catalyzed construction of ketones through Suzuki–Miyaura reaction by using acid fluorides is described. In contrast to typical acyl electrophiles such as acid chlorides, acid fluorides are uncommon acyl electrophiles to use in boron-based coupling reactions, probably due to a high level of stability toward nucleophiles. This first attempt to use acid fluorides as a coupling partner with boronic acids allowed highly functional group tolerance and a wide substrate scope while affording various ketones in effective yields.
N-(2-Aminobenzylidene)-4-methylanilines - stable and cheap alternate for 2-aminobenzaldehydes: concise synthesis of 3-unsubstituted-2-aroylindoles
Vivekanand, Thavaraj,Sandhya, Thiruvalluvan,Vinoth, Perumal,Nagarajan, Subbiah,Maheswari, C. Uma,Sridharan, Vellaisamy
, p. 5291 - 5294 (2015)
Abstract Synthesis of 3-unsubstituted-2-aroylindoles starting from readily available N-(2-aminobenzylidene)-4-methylanilines, cheap and stable alternative to 2-aminobenzaldehydes, and α-bromoketones was achieved in moderate to good yields under basic cond
Incvestigation of the possible role of arylamine formation in the ortho-substituted nitroarenes reductive cyclization reactions to afford heterocycles
Ragaini, Fabio,Sportiello, Paola,Cenini, Sergio
, p. 283 - 291 (1999)
Reductive carbonylation of nitroarenes with an unsaturated group in the ortho position generally affords high yields of heterocyclic compounds, including indoles, chalcones, quinolines, benzimidazoles, benzotriazoles, and indazoles. There is, however, no direct information on the organic intermediates formed during the reaction. In this paper, we have examined the possible formation of anilines as intermediates in the synthesis of indoles, acylindoles, quinolines, and quinolones with several catalytic systems based on palladium, ruthenium and rhodium. It transpired that, independent of the metal complex used as a catalyst, the formation of aniline as an intermediate is essential in the intra-molecular condensation reactions of nitroarenes involving an aldehydic or a keto group (including Michael addition reactions), but plays at best a very limited role in the addition reactions involving a C=C double bond.
Synthesis of 2-Acylindoles via Ag- and Cu-Catalyzed anti-Michael Hydroamination of β-(2-Aminophenyl)-α,β-ynones: Experimental Results and DFT Calculations
Rode, Navnath D.,Abdalghani, Issam,Arcadi, Antonio,Aschi, Massimiliano,Chiarini, Marco,Marinelli, Fabio
, p. 6354 - 6362 (2018)
β-(2-Aminophenyl)-α,β-ynones afforded 3-unsubstituted 2-acylindoles in good yields in the presence of 20 mol % AgOTf under (microwave) MW heating. The use CuOTf as a catalyst resulted in a similar reaction outcome, generally with a lower efficiency. This transformation represents the first example of 5-endo-dig cyclization of 2-alkynylanilines bearing an acyl group linked to the triple bond. By contrast with the previously reported gold-catalyzed reaction of β-(2-aminophenyl)-α,β-ynones, which resulted in the formation of dibenzo[1,5]diazocines through a sequential process triggered by an intermolecular hydroamination, a selective intramolecular anti-Michael hydroamination was observed in the present study by silver/copper catalysis. Density functional theory calculations on the Ag-catalyzed reaction revealed that the catalyst induces an electrostatic arrangement in the TS coherent with the experimentally observed cyclization.
Reaction of 3-(2-nitrophenyl)-1-arylprop-2-en-1-ones with triethylphosphite in microwave revisited: One-pot synthesis of 2-aroylindoles and 2-arylquinolines
Gupta, Annah,Khajuria, Rajni,Kapoor, Kamal K.
, p. 31 - 38 (2016)
One-pot synthesis of 2-aroylindoles and 2-arylquinolines has been achieved by the reductive cyclization of 3-(2-nitrophenyl)-1-arylprop-2-en-1-ones with triethylphosphite [P(OEt)3] under microwave irradiation. The formation of 2-arylquinolines by this method is unprecedented.
Substrate-Controlled Transformation of Azobenzenes to Indazoles and Indoles via Rh(III)-Catalysis
Cai, Shangjun,Lin, Songyun,Yi, Xiangli,Xi, Chanjuan
, p. 512 - 520 (2017)
Rh(III)-catalyzed substrate-controlled transformation of azobenzenes to indazoles and 2-acyl (NH) indoles is achieved via C-H functionalization. Generally, good functional groups tolerance, satisfying yields, and excellent regio-selectivity are achieved in this reaction. Mechanistically, the reaction with acrylates undergoes β-hydride elimination, while the reaction with vinyl ketones or acrylamides undergoes nucleophilic addition. Copper acetate was supposed to play different roles in the β-hydride elimination to furnish indazoles and nucleophilic addition of C-Rh bond to deliver 2-acyl (NH) indoles.
Diethoxymethyl protected indoles: Synthesis and regioselective transformations
Gmeiner, Peter,Kraxner, Johannes,Bollinger, Bernd
, p. 1196 - 1198 (1996)
Reaction of the indoles 1a-d with triethyl orthoformate gives access to the N-diethoxymethyl derivatives 2a-d. Convenient and mild removal of the diethoxymethyl substituent is possible by subsequent treatment of 2a-d with aqueous HCl and NaOH. Using 2a as an example, it could be shown that deprotonation followed by addition of an electrophile (Me3SiCl or Bu3SnCl) leads to substitution in position 2. Further functionalization was possible by palladium-catalyzed coupling reactions starting from the stannane 4. The diethoxymethyl protected η6-tricarbonylchromium complex 5 facilitated acylation in position 2 after deprotonation.
Novel Synthesis of Indoles via Palladium-Catalyzed Reductive N-Heterocyclization of o-Nitrostyrene Derivatives
Akazome, Motohiro,Kondo, Teruyuki,Watanabe, Yoshihisa
, p. 769 - 772 (1992)
Indole derivatives were readily prepared from the reductive N-heterocyclization of o-nitrostyrene derivatives in the presence of a catalytic amount of PdCl2(PPh3)2 - SnCl2 under carbon monoxide pressure (20 kg/cm2) at 100 deg C for 16 h.With o-nitrostilbene, 2-phenylindole was obtained in 75percent yield.
Synthesis of N-Heterocycles by Reductive Cyclization of Nitro Compounds using Formate Esters as Carbon Monoxide Surrogates
Formenti, Dario,Ferretti, Francesco,Ragaini, Fabio
, p. 148 - 152 (2018)
A series of alkyl and aryl formate esters were evaluated as CO sources in the Pd- and Pd/Ru-catalyzed reductive cyclization of substituted nitro compounds to afford heterocycles, especially indoles. Phenyl formate was found to be the most effective, and it allowed the desired products to be obtained in excellent yields, often higher than those previously reported with pressurized CO. Through detailed experiments and kinetic studies, we were able to discern between metal-catalyzed and base-mediated activation of phenyl formate and confirmed that just the base was effective in catalyzing its decarbonylation.
Selective synthesis of quinolines and indoles: Sulfur-assisted or selenium-catalyzed reaction of β-(2-nitrophenyl)-α, β-unsaturated ketones with carbon monoxide
Umeda, Rui,Kouno, Hiroshi,Kitagawa, Takayuki,Okamoto, Tomohiro,Kawashima, Keisuke,Mashino, Tsukasa,Nishiyama, Yutaka
, p. 698 - 703 (2014)
A simple and selective synthetic method of quinolines and indoles by the reaction of β- (2-nitrophenyl)-α,β-unsaturated ketones with carbon monoxide was developed. When β-(2-nitrophenyl)- α,β-unsaturated ketones were allowed to react with carbon monoxide and water in the presence of a stoichiometric amount of sulfur or a catalytic amount of selenium, the corresponding quinolines were produced in moderate-to-good yields. On the other hand, in the absence of water, the indoles were produced by the selenium-catalyzed reaction of the β-(2-nitrophenyl)- α,β-unsaturated ketones with carbon monoxide.
