55577-25-8Relevant academic research and scientific papers
2-(Methoxycarbonyl)ethyl as a removable N-protecting group: Synthesis of indoloisoquinolinones by pd(II)-catalyzed intramolecular diamination of alkynes
Ha, Tu M.,Yao, Bo,Wang, Qian,Zhu, Jieping
, p. 1750 - 1753 (2015)
Pd(II)-catalyzed double cyclization of 1,2-diarylethynes bearing an N-methyl-N-[2-(methoxycarbonyl)ethyl]amino and an aminocarbonyl group at the ortho positions of the two aromatic rings afforded the tetracyclic N-[2-(methoxycarbonyl)ethyl]indoloisoquinolinones in good to excellent yields. The N-[2-(methoxycarbonyl)ethyl] group is readily removed under basic conditions (DBU, DMF, 120 °C) to afford the corresponding tetracycles with a free indolyl nitrogen in excellent yields. The 2-(methoxycarbonyl)ethyl as a removable N-protecting group is illustrated in other Pd(II)- and Pd(0)-catalyzed and selenium-mediated transformations.
Catellani type N-H activation of indole derivatives and resolution of palladium complexes containing norbornene or dicyclopentadiene moieties
Chen, Ya-Qian,Hong, Fung-E.
, p. 7016 - 7025 (2015)
The reactions of indole (1) with iodotoluene in the presence of norbornene or dicyclopentadiene led to the formation of indole derivative (2a). It is through the C-H activation at ortho-position of indole by Catellani-type reactions. Besides, several palladium complexes (4a, 4b, 5a, 5b, 6a, and 6b), containing either single or double norbornene or dicyclopentadiene fragments via insertion into the Pd-C(aryl) bond of the formerly formed palladium-containing intermediate, were obtained and characterized by spectroscopic means as well as by X-ray diffraction methods. The ratios of 2a to 5a could be altered by employing different palladium sources. Triple insertion of norbornene or dicyclopentadiene into the Pd-C(aryl) bond was not observed.
One-Pot Asymmetric Oxidative Dearomatization of 2-Substituted Indoles by Merging Transition Metal Catalysis with Organocatalysis to Access C2-Tetrasubstituted Indolin-3-Ones
Zhao, Yong-Long,An, Jian-Xiong,Yang, Fen-Fen,Guan, Xiang,Fu, Xiao-Zhong,Li, Zong-Qin,Wang, Da-Peng,Zhou, Meng,Yang, Yuan-Yong,He, Bin
, p. 1277 - 1285 (2022/03/14)
A one-pot approach for the asymmetric synthesis of C2-tetrasubstituted indolin-3-ones from 2-substituted indoles was developed via merging transition metal catalysis with organocatalysis. This strategy involves two processes, including CuI catalyzed oxidative dearomatization of 2-substituted indoles using O2 as green oxidant, and followed by an proline-promoted asymmetric Mannich reaction with ketones or aldehydes. A series of C2-tetrasubstituted indolin-3-ones were obtained in 35–86% yields, 2:1->20:1 dr and 48–99% ee. Moreover, the synthetic 2-tetrasubstituted indolin-3-ones could be easily transformed into 1H-[1,3] oxazino [3,4-a]indol-5(3H)-ones via a [4+1] cyclization process. In addition, the synthetic compound 3 s show certain antibacterial activity against S. aureus ATCC25923 and multi-drug resistance bacterial strain of S. aureus (20151027077) and its MIC values up to 8 μg/mL and 16 μg/mL, respectively. (Figure presented.).
Palladium-Catalyzed Aminocyclization-Coupling Cascades: Preparation of Dehydrotryptophan Derivatives and Computational Study
Vaz, Belén,Martínez, Claudio,Cruz, Francisco,Denis, J. Gabriel,De Lera, ángel R.,Aurrecoechea, José M.,álvarez, Rosana
, p. 8766 - 8785 (2021/06/30)
Dehydrotryptophan derivatives have been prepared by palladium-catalyzed aminocyclization-Heck-type coupling cascades starting from o-alkynylaniline derivatives and methyl α-aminoacrylate. Aryl, alkyl (primary, secondary, and tertiary), and alkenyl substituents have been introduced at the indole C-2 position. Further variations at the indole benzene ring, as well as the C-2-unsubstituted case, have all been demonstrated. In the case of C-2 aryl substitution, the preparation of the o-alkynylaniline substrate by Sonogashira coupling and the subsequent cyclization-coupling cascade have been performed in a one-pot protocol with a single catalyst. DFT calculations have revealed significant differences in the reaction profiles of these reactions relative to those involving methyl acrylate or methacrylate, and between the reactions of the free anilines and their corresponding carbamates. Those calculations suggest that the nature of the alkene and of the acid HX released in the HX/alkene exchange step that precedes C-C bond formation could be responsible for the experimentally observed differences in reaction efficiencies.
Aniline-initiated and Br?nsted acid-catalyzed one-pot reaction toward 2-aryl-3-sulfenylindoles by using α-aminocarbonyl compounds and primary amines with RSSR
Chen, De,Cheng, Chaozhihui,Deng, Wei,Guan, Wenjian,Liu, Yuxuan,Luo, Yongyue,Xiang, Jiannan,Zhang, Jiajia
, (2020/12/01)
A highly novel method of direct synthesis of 2-aryl-3-sulfenylindoles in moderate to good yields was developed via one-pot tandem reaction of readily available α-aminocarbonyl compounds and catalytic amount of benzenamines with RSSR.
Iron-catalysed radical cyclization to synthesize germanium-substituted indolo[2,1-a]isoquinolin-6(5H)-ones and indolin-2-ones
Luo, Yani,Tian, Tian,Nishihara, Yasushi,Lv, Leiyang,Li, Zhiping
supporting information, p. 9276 - 9279 (2021/09/20)
A simple and efficient strategy for iron-catalysed cascade radical cyclization was developed, by which an array of germanium-substituted indolo[2,1-a]isoquinolin-6(5H)-ones and indolin-2-ones were obtained in one pot with germanium hydrides as radical precursors. A rapid intramolecular radical trapping mode enabled the selective arylgermylation of alkenes over the prevalent hydrogermylation reaction.
Regioselective Direct C2 Arylation of Indole, Benzothiophene and Benzofuran: Utilization of Reusable Pd NPs and NHC-Pd@MNPs Catalyst for C–H Activation Reaction
Hegde, Rajeev V.,Ong, Tiow-Gan,Ambre, Ram,Jadhav, Arvind H.,Patil, Siddappa A.,Dateer, Ramesh B.
, p. 1397 - 1405 (2020/10/02)
Abstract: A regioselective C2 arylation of indoles, benzothiophene and benzofuran without directing group has been accomplished using economically cheap Pd NPs and NHC-Pd@MNPs catalyst. The reusable catalyst is efficiently employed to access C2 arylated heterocycles in good to excellent yield. The reusability of the catalyst is studied up to five cycles and a gram-scale synthesis has been achieved. The reaction mechanism is well supported by control experiments and literature precedents. Grapic Abstract: [Figure not available: see fulltext.]
Synthesis and Catalytic Use of Polar Phosphinoferrocene Amidosulfonates Bearing Bulky Substituents at the Ferrocene Backbone
Vosáhlo, Petr,Radal, Leá,Labonde, Marine,Císa?ová, Ivana,Roger, Julien,Pirio, Nadine,Hierso, Jean-Cyrille,?těpni?ka, Petr
, p. 1934 - 1944 (2021/06/28)
Anionic phosphinoferrocene amidosulfonates bearing sterically demanding tert-butyl substituents in positions 3 and 3′ of the ferrocene scaffold, viz. rac-(Et3NH)[Fe(η5-tBuC5H3PR2)(η5-tBuC5H3C(O)NHCH2SO3)] (R = phenyl, cyclohexyl), were synthesized by amidation of the corresponding phosphinocarboxylic acids, [Fe(η5-tBuC5H3PR2)(η5-tBuC5H3CO2H)]. These ditopic polar phosphinoferrocenes and their non-tert-butylated analogues have been used as ligands to prepare zwitterionic (η3-allyl)palladium(II) complexes [Pd(η3-C3H5){Fe(η5-R′C5H3PR2)(η5-R′C5H3C(O)NHCH2SO3)}] (R′ = H, tBu; R = Ph, Cy). Depending on the isolation procedure and crystallization conditions, some complexes were isolated in two isomeric forms which differed in the coordination of the amidosulfonate pendant group, where either amide or sulfonated oxygen ligated the Pd(II) center. The preference for coordination of the amide or sulfonate oxygen atoms has been explained by the interplay of electrostatic and solvation effects and further supported by DFT calculations. The (η3-allyl)PdII complexes have been applied as defined precatalysts for Pd-catalyzed C-H arylation of an unprotected indole with aryl iodides in polar solvents. Under the optimized reaction conditions at 100 °C in water, C2-arylation proceeded selectively with various aryl iodides to produce the respective 2-arylindoles in acceptable yields at a low catalyst loading (1 mol % Pd) and in the absence of any phase transfer agent. The catalyst possessing tert-butyl groups at the ferrocene core and an electron-rich dicyclohexylphosphino group exhibited the best catalytic performance.
B(C6F5)3-Catalyzed Electron Donor-Acceptor Complex-Mediated Aerobic Sulfenylation of Indoles under Visible-Light Conditions
Yuan, Wenkai,Huang, Jie,Xu, Xin,Wang, Long,Tang, Xiang-Ying
supporting information, p. 7139 - 7143 (2021/09/14)
An efficient B(C6F5)3-catalyzed aerobic oxidative C-S cross-coupling reaction of thiophenol with indoles was developed, affording a wide range of diaryl sulfides in good yields. An electron donor-acceptor complex between B(C6F5)3 and indoles was formed, facilitating the photoinduced single-electron transfer (SET) from indole substrates to the B(C6F5)3 catalyst. This protocol demonstrates a new reaction model using B(C6F5)3 as a single-electron oxidant.
Acid-catalyzed cleavage of C-C bonds enables atropaldehyde acetals as masked C2 electrophiles for organic synthesis
Chen, Shaomin,Gu, Yanlong,Li, Minghao
supporting information, p. 10431 - 10434 (2021/10/12)
Acid-catalyzed tandem reactions of atropaldehyde acetals were established for the synthesis of three important molecules, 2,2-disubstituted indolin-3-ones, naphthofurans and stilbenes. The synthesis was realized using novel reaction cascades, which involved the same two initial steps: (i) SN2′ substitution, in which the atropaldehyde acted as an electrophile; and (ii) oxidative cleavage of the carbon-carbon bond of the generated phenylacetaldehyde-type products. Compared with literature methods, the present protocol not only avoided the use of expensive noble metal catalysts, but also enabled a simple operation.
