5221-67-0Relevant articles and documents
Oxidative Access via Aqua Regia to an Electrophilic, Mesoionic Dicobaltoceniumyltriazolylidene Gold(III) Catalyst
Vanicek, Stefan,Beerhues, Julia,Bens, Tobias,Levchenko, Volodymyr,Wurst, Klaus,Bildstein, Benno,Tilset, Mats,Sarkar, Biprajit
, p. 4383 - 4386 (2019)
A gold(III) complex with the hitherto most electron poor mesoionic carbene ligand is presented. Aqua regia was the oxidizing agent of choice for the synthesis of this unusual organometallic compound. The AuIII complex is redox-rich and also act
Heterogenized gold(I)-carbene as a single-site catalyst in continuous flow
Lothschuetz, Christian,Szlachetko, Jakub,Van Bokhoven, Jeroen A.
, p. 443 - 448 (2014)
Catalytically active gold(I)-carbene complexes on a polystyrene backbone were synthesized by treating metal-coordinated isocyanides with the nitrogen nucleophile of a piperazine group bonded to the polystyrene. The local environment of the metal was readi
Rh(iii)-Catalyzed three-component cascade annulation to produce theN-oxopropyl chain of isoquinolone derivatives
He, Yuan,Liao, Xian-Zhang,Dong, Lin,Chen, Fen-Er
supporting information, p. 561 - 567 (2021/02/06)
Developing powerful methods to introduce versatile functional groups at theN-substituents of isoquinolone scaffolds is still a great challenge. Herein, we report a novel three-component cascade annulation reaction to efficiently construct theN-oxopropyl chain of isoquinolone derivativesviarhodium(iii)-catalyzed C-H activation/cyclization/nucleophilic attack, with oxazoles used both as the directing group and potential functionalized reagents.
Synthesis and Catalytic Activity of Atrane-type Hard and Soft Lewis Superacids with a Silyl, Germyl, or Stannyl Cationic Center
Tanaka, Daiki,Konishi, Akihito,Yasuda, Makoto
supporting information, p. 3118 - 3123 (2021/09/08)
The synthesis and isolation of atrane-type molecules 1E+ (E=Si, Ge, or Sn) having a cationic group 14 elemental center are reported. The cations 1E+ act as hard and soft Lewis superacids, which readily interact with various hard and soft Lewis basic substrates. The rigid atrane framework stabilizes the localized positive charge on the elemental center and assists the formation of the well-defined highly coordinated states of 1E+. The cations were applied to the hydrodefluorination, Friedel-Crafts reaction, alkyne cyclization, and carbonyl reduction as Lewis acid catalysts. Most notably, [1Si][ClO4] exhibits unique chemoselectivity that depends on a solvent in the competitive reaction of silyl enol ether with a mixture of benzaldehyde dimethyl acetal and benzaldehyde. Our findings indicate the potential of hard and soft Lewis superacids in organic synthesis.
Asymmetric Allylation by Chiral Organocatalyst-Promoted Formal Hetero-Ene Reactions of Alkylgold Intermediates
Dong, Guizhi,Bao, Ming,Xie, Xiongda,Jia, Shikun,Hu, Wenhao,Xu, Xinfang
, p. 1992 - 1999 (2020/11/30)
An unprecedented catalytic asymmetric allylation of isatins and isatin-derived ketimines is reported enabled by a gold and chiral organocatalyst cooperative catalysis strategy. This method offers expeditious access to chiral 2,5-disubsituted alkylideneoxazolines containing vicinal stereogenic centers, mainly in optically pure form, and which are otherwise impossible to access. Mechanistic evidence reveals the presence of an alkylgold intermediate, and an X-ray crystal structure of the allylgold species illuminates its unique stability and reactivity. An asymmetric formal hetero-ene reaction of this gold intermediate, involving a dearomatization process, is enabled with assistance of a quinine-derived squaramide catalyst. This novel discovery extends the synthetic applications of gold complexes and the versatility of gold catalysis.
Silver-Free Au(I) Catalysis Enabled by Bifunctional Urea- and Squaramide-Phosphine Ligands via H-Bonding
Echavarren, Antonio M.,Franchino, Allegra,Martí, àlex,Nejrotti, Stefano
, p. 11989 - 11996 (2021/07/06)
A library of gold(I) chloride complexes with phosphine ligands incorporating pendant (thio)urea and squaramide H-bond donors was prepared with the aim of promoting chloride abstraction from Au(I) via H-bonding. In the absence of silver additives, complexes bearing squaramides and trifluoromethylated aromatic ureas displayed good catalytic activity in the cyclization of N-propargyl benzamides, as well as in a 1,6-enyne cycloisomerization, a tandem cyclization-indole addition reaction and the hydrohydrazination of phenylacetylene. Kinetic studies and DFT calculations indicate that the energetic span of the reaction is accounted by both the chloride abstraction step, facilitated by the bidentate H-bond donor via an associative mechanism, and the subsequent cyclization step.
Silica-Supported Phosphine–Gold Complexes as an Efficient Catalytic System for a Dearomative Spirocyclization
Bibal, Brigitte,Buffière, Sonia,Cao, Zhen,Nlate, Sylvain,Oda, Reiko,Pouget, Emilie,Scalabre, Antoine
, p. 427 - 433 (2020/12/03)
The combination of metal catalyst and inorganic silica frameworks provides a greener approach to recyclable catalysis. In this study, three phosphine–gold chloride complexes have been successfully covalently grafted onto chiral silica nanohelices. The resulting 3D ensembles showed chiroptical properties that allowed the monitoring of the supported ligands. The heterogeneous gold chloride catalysts in cooperation with silver triflate exhibited high reactivity in various reactions, especially in the spirocyclization of aryl alkynoate esters, for which a catalytic loading of 0.05 mol % could be employed. The heterogeneous catalysts could be easily recovered and recycled seven or eight times without any loss of efficiency. By adding more silver triflate, 25 cycles with full conversion were achieved owing to a complex catalytic system based on silica and metallic species.
InCl3-catalyzed 5- exo-dig cyclization/1,6-conjugate addition of N -propargylamides with p -QMs to construct oxazole derivatives
Li, Ming,Li, Xue,Nan, Guang-Ming,Wen, Li-Rong,Yan, Ting-Xun,Yao, Tian-Yu
supporting information, p. 1780 - 1784 (2020/03/17)
An InCl3-catalyzed atom-economic intramolecular 5-exo-dig cyclization/1,6-conjugate addition/aromatization of N-propargylamides with p-QMs to produce oxazoles tethering diarylmethane has been successfully developed. InCl3 not only se
Deep eutectic solvent-catalyzed Meyer-Schuster rearrangement of propargylic alcohols under mild and bench reaction conditions
Ríos-Lombardía, Nicolás,Cicco, Luciana,Yamamoto, Kota,Hernández-Fernández, José A.,Morís, Francisco,Capriati, Vito,García-álvarez, Joaquín,González-Sabín, Javier
supporting information, p. 15165 - 15168 (2020/12/21)
The Meyer-Schuster rearrangement of propargylic alcohols into α,β-unsaturated carbonyl compounds has been revisited by setting up an atom-economic process catalyzed by a deep eutectic solvent FeCl3·6H2O/glycerol. Isomerizations take place smoothly, at room temperature, under air and with short reaction times. The unique solubilizing properties of the eutectic mixture enabled the use of a substrate concentration up to 1.0 M with the medium being recycled up to ten runs without any loss of catalytic activity. This journal is
Bi(iii)-catalyzed aminooxygenation of propargyl amidines to synthesize 2-fluoroalkyl imidazole-5-carbaldehydes and their decarbonylations
Li, Shan,Li, Yajun,Feng, Bin,Liang, Jian,You, Geyun,Liu, Xiaofeng,Xian, Liqing
supporting information, p. 6400 - 6403 (2020/06/21)
The first example of main group metal Bi(iii)-catalyzed aminooxygenation of fluorinated propargyl amidines was developed to produce 2-fluoroalkyl imidazole-5-carbaldehydes in moderate to excellent yields, in which phenol played a critical role and could be recovered and recycled. In the presence of KOt-Bu, an unconventional decarbonylation occurred on the 2-fluoroalkyl imidazole-5-carbaldehydes.