4903-36-0Relevant academic research and scientific papers
Novel Conjugated s-Tetrazine Derivatives Bearing a 4H-1,2,4-Triazole Scaffold: Synthesis and Luminescent Properties
?wiatkowski, Marcin,Kudelko, Agnieszka,Maj, Anna
, (2022/01/20)
A series of new symmetrical s-tetrazine derivatives, coupled via a 1,4-phenylene linkage with a 4H-1,2,4-triazole ring, were obtained. The combination of these two rings in an extensively coupled system has significant potential applications, mainly in op
Br?nsted Base-Catalyzed Formal Reductive [3+2] Annulation of 4,4,4-Trifluorocrotonate and α-Iminoketones
Kondoh, Azusa,Terada, Masahiro
supporting information, p. 585 - 588 (2020/12/07)
A formal reductive [3+2] annulation of 4,4,4-trifluorocrotonate and α-iminoketones was developed under Br?nsted base catalysis. A single phosphazene base efficiently catalyzes the one-pot tandem reaction involving two mechanistically different elementary processes, namely the chemoselective reduction of an imine moiety of α-iminoketones with thiols as the reductant and the subsequent intermolecular Michael addition of an enolate of α-aminoketones concomitant with lactam formation. This operationally simple method provides β-trifluoromethyl-substituted γ-lactams with a tetrasubstituted carbon as a single diastereomer.
Synthesis of Imidoyl Chlorides Using Phosphorus Trichloride
Nguyen, T. L.,Popov, Yu. V.,Shishkin, E. V.,Shishkin, V. E.,Vo, T. L. Q.,Zotov, Yu. L.
, p. 849 - 851 (2021/06/12)
Abstract: The reaction of carboxamides with phosphorus trichloride under heating at 75–80°C for 1 h in the presence of a 4-dimethylaminopyridine catalyst was used to synthesize imidoyl chlorides in yields of 63–99%.
Regioselective Synthesis of Trisubstituted Quinoxalines Mediated by Hypervalent Iodine Reagents
Ito, Ryota,Miura, Kasumi,Suzuki, Noriyuki,Suzuki, Yumiko,Takehara, Ren
, p. 16892 - 16900 (2021/12/06)
A facile and regioselective synthesis of quinoxalines, an important motif in medicinal chemistry and materials sciences, was developed. Despite their prospective utility, the regioselective preparation of trisubstituted quinoxalines has not been previously established. In the reported system, hypervalent iodine reagents catalyzed the annulation between α-iminoethanones ando-phenylenediamines in a chemo/regioselective manner to afford trisubstituted quinoxalines. Excellent regioselectivities (6:1 to 1:0) were achieved using [bis(trifluoroacetoxy)iodo]benzene and [bis(trifluoroacetoxy)iodo]pentafluorobenzene as annulation catalysts.
Hydrogenation of Secondary Amides using Phosphane Oxide and Frustrated Lewis Pair Catalysis
K?ring, Laura,Sitte, Nikolai A.,Bursch, Markus,Grimme, Stefan,Paradies, Jan
supporting information, p. 14179 - 14183 (2021/09/03)
The metal-free catalytic hydrogenation of secondary carboxylic acid amides is developed. The reduction is realized by two new catalytic reactions. First, the amide is converted into the imidoyl chloride by triphosgene (CO(OCCl3)2) using novel phosphorus(V) catalysts. Second, the in situ generated imidoyl chlorides are hydrogenated in high yields by an FLP-catalyst. Mechanistic and quantum mechanical calculations support an autoinduced catalytic cycle for the hydrogenation with chloride acting as unusual Lewis base for FLP-mediated H2-activation.
Synthesis of Nitrogen-Containing Polyaromatics by Aza-Annulative π-Extension of Unfunctionalized Aromatics
Itami, Kenichiro,Ito, Hideto,Kawahara, Kou P.,Matsuoka, Wataru
supporting information, p. 6383 - 6388 (2020/03/13)
Nitrogen-containing polycyclic aromatic compounds (N-PACs) are an important class of compounds in materials science. Reported here is a new aza-annulative π-extension (aza-APEX) reaction that allows rapid access to a range of N-PACs in 11–84 % yields from readily available unfunctionalized aromatics and imidoyl chlorides. In the presence of silver hexafluorophosphate, arenes and imidoyl chlorides couple in a regioselective fashion. The follow-up oxidative treatment with p-chloranil affords structurally diverse N-PACs, which are very difficult to synthesize. DFT calculations reveal that the aza-APEX reaction proceeds through the formal [4+2] cycloaddition of an arene and an in situ generated diarylnitrilium salt, with sequential aromatizations having relatively low activation energies. Transformation of N-PACs into nitrogen-doped nanographenes and their photophysical properties are also described.
α-Imino Iridium Carbenes from Imidoyl Sulfoxonium Ylides: Application in the One-Step Synthesis of Indoles
Burtoloso, Antonio C. B.,Caiuby, Clarice A. D.,De Jesus, Matheus P.
, p. 7433 - 7445 (2020/06/27)
Imidoyl sulfoxonium ylides are presented for the first time as potential precursors to generate α-imino metal-carbene intermediates and applied in direct C-H functionalization reactions catalyzed by [Ir(cod)Cl]2 (4 mol %) to provide 2-substituted indoles (up to 70% yield) in just one step. This class of sulfur ylide is successfully obtained from imidoyl chloride and dimethylsulfoxonium methylide (23 new examples in 45-85% yield) or by imino group formation from the corresponding β-keto sulfoxonium ylides and anilines in the presence of TiCl4 as a Lewis acid (9 examples in 33-94% yield).
Silver-Catalyzed Cascade Cyclization Reaction of Isocyanides with Sulfoxonium Ylides: Synthesis of 3-Aminofurans and 4-Aminoquinolines
Liang, Yong-Xin,Yang, Ming,He, Bo-Wen,Zhao, Yu-Long
supporting information, p. 7640 - 7644 (2020/10/09)
A silver-catalyzed cascade cyclization reaction of isocyanides with sulfoxonium ylides has been developed for the first time. This reaction provides a new and efficient method for the construction of highly functionalized 3-aminofurans and 4-aminoquinolines from readily available starting materials in a single step.
The impact of cation structure upon the acidity of triazolium salts in dimethyl sulfoxide
Konstandaras, Nicholas,Dunn, Michelle H.,Guerry, Max S.,Barnett, Christopher D.,Cole, Marcus L.,Harper, Jason B.
, p. 66 - 75 (2019/12/26)
A series of triazolium salts, selected for their varying electronic and steric properties, were prepared and their pKa values were determined in DMSO at 25 °C using the bracketing indicator method. The effect of each systematic structural variation upon the acidity of the triazolium cation has been considered, in particular examining the effects of systematically altering electronic properties, quantified through the use of Hammett σ parameters. The first pKa value for an azolium salt that generates a mesionic carbene is also reported. These new data allow for the selection of appropriate bases for the deprotonation of such triazolium salts and the potential to correlate the pKa values determined herein with the nucleophilicity of the corresponding carbenes.
1,1-Diphosphines and divinylphosphines via base catalyzed hydrophosphination
Coles,Mahon,Webster
supporting information, p. 10443 - 10446 (2018/09/21)
A catalytic hydrophosphination route to 1,1-diphosphines is yet to be reported: these narrow bite angle pro-ligands have been used to great effect as ligands in homogeneous catalysis. We herein demonstrate that terminal alkynes readily undergo double hydrophosphination with HPPh2 and catalytic potassium hexamethyldisilazane (KHMDS) to generate 1,1-diphosphines. A change to H2PPh leads to the formation of P,P-divinyl phosphines.
