38940-36-2Relevant academic research and scientific papers
Highly Enantioselective Construction of Dihydrooxazines via Pd-Catalyzed Asymmetric Carboetherification
Li, Na,Sun, Baozhen,Liu, Shuang,Zhao, Jinbo,Zhang, Qian
supporting information, p. 190 - 193 (2020/01/02)
A straightforward synthesis of highly enantioenriched 5,6-dihydro-4H-1,2-oxazines is realized by Pd-catalyzed asymmetric carboetherification of γ,δ-alkenyl oximes with (hetero)aryl and alkenyl halides in the presence of a commercially available bisphosphine ligand. The enantioenriched products can be facilely converted to functionalized alcohols with high fidelity of chiral transfer.
Copper-Catalyzed Cope-Type Hydroamination of Nonactivated Olefins toward Cyclic Nitrones: Scope, Mechanism, and Enantioselective Process Development
Zhang, Mengru,Liu, Shuang,Li, Hexin,Guo, Yajing,Li, Na,Guan, Meihui,Mehfooz, Haroon,Zhao, Jinbo,Zhang, Qian
supporting information, p. 12620 - 12627 (2019/09/16)
The catalytic synthesis of cyclic nitrones, an important type of functional molecules for both synthetic chemistry and related fields, remains underdeveloped. Herein we report the copper-catalyzed Cope-type hydroamination of oximes with pendant nonactivated olefins, which enables facile access to a series of five- and six-membered cyclic nitrones under mild conditions. In this study, heterocycle-tethered oximes were employed in the Cope-type hydroamination reaction for the first time. High enantioselectivity was achieved for carbon-tethered γ,δ-vinyl oximes to afford enantioenriched five-membered cyclic nitrones. The results of preliminary mechanistic studies indicate a mononuclear catalytic species and a unified catalytic pathway over a large temperature range.
Chiral AuI- and AuIII-Isothiourea Complexes: Synthesis, Characterization and Application
Gasperini, Danila,Greenhalgh, Mark D.,Imad, Rehan,Siddiqui, Shezaib,Malik, Anum,Arshad, Fizza,Choudhary, Muhammad Iqbal,Al-Majid, Abdullah M.,Cordes, David B.,Slawin, Alexandra M. Z.,Nolan, Steven P.,Smith, Andrew D.
supporting information, p. 1064 - 1075 (2019/01/04)
During an investigation into the potential union of Lewis basic isothiourea organocatalysis and gold catalysis, the formation of gold-isothiourea complexes was observed. These novel gold complexes were formed in high yield and were found to be air- and moisture stable. A series of neutral and cationic chiral gold(I) and gold(III) complexes bearing enantiopure isothiourea ligands was therefore synthesized and fully characterized. The steric and electronic properties of the isothiourea ligands was assessed through calculation of their percent buried volume and the synthesis and analysis of novel iridium(I)-isothiourea carbonyl complexes. The novel gold(I)- and gold(III)-isothiourea complexes have been applied in preliminary catalytic and biological studies, and display promising preliminary levels of catalytic activity and potency towards cancerous cell lines and clinically relevant enzymes.
Inner-Sphere versus Outer-Sphere Coordination of BF4- in a NHC-Gold(I) Complex
Veenboer, Richard M. P.,Collado, Alba,Dupuy, Stéphanie,Lebl, Tomas,Falivene, Laura,Cavallo, Luigi,Cordes, David B.,Slawin, Alexandra M. Z.,Cazin, Catherine S. J.,Nolan, Steven P.
supporting information, p. 2861 - 2869 (2017/08/21)
The role of counterions in chemistry mediated by gold complexes stretches much further than merely providing charge balance to cationic gold species. Interplay between their basicities and coordination strengths influences interactions with both the gold center and substrates in catalysis. Actual monogold(I) active species are generally believed to be monocoordinated species, formed from the abstraction or the decoordination of a second ligand from precursor complexes, but only a small amount of experimental evidence exists to underpin the existence of these transient species. The formation of a bench-stable neutral IPrCl-gold(I) tetrafluoroborate complex is reported herein. Experimental studies by X-ray diffraction analysis and NMR spectroscopy and theoretical studies by DFT calculations were conducted to determine the composition, structure, and behavior of this complex. The absence of an auxiliary ligand resulted in inner-sphere coordination of the counterion in the solid state. In solution, an equilibrium between two conformations was found with the counterion occupying inner-sphere and outer-sphere positions, respectively. Stoichiometric and catalytic reactivity studies with the tetrafluoroborate complex have been conducted. These confirmed the lability of the inner-sphere coordinating counterion that gives the IPrCl-gold(I) fragment behavior similar to that of related systems.
Copper-catalyzed cyclization and azidation of γ,δ-unsaturated ketone O-benzoyl oximes
Su, Hailin,Li, Weifei,Xuan, Zhaoli,Yu, Wei
supporting information, p. 64 - 70 (2015/03/04)
An intramolecular imination/azidation sequence has been realized through the tetrakis(acetonitrile)copper(I) hexafluorophophate [Cu(CH3CN)4PF6]-catalyzed reaction of γ,δ-unsaturated ketone O-benzoyl oximes with trimethylsi
Ascorbic Acid Promoted Oxidative Arylation of Vinyl Arenes to 2-Aryl Acetophenones without Irradiation at Room Temperature under Aerobic Conditions
Majhi, Biju,Kundu, Debasish,Ranu, Brindaban C.
, p. 7739 - 7745 (2015/08/18)
A convenient and general protocol for oxidative arylation of vinyl arenes by aryl radicals generated in situ from arene diazonium fluoroborates promoted by ascorbic acid in air at room temperature has been developed in the absence of any additive and visible light irradiation. A series of diversely substituted 2-aryl acetophenones have been obtained in good yields by this procedure.
Influence of bulky yet flexible N-heterocyclic carbene ligands in gold catalysis
Collado, Alba,Patrick, Scott R.,Gasperini, Danila,Meiries, Sebastien,Nolan, Steven P.
supporting information, p. 1809 - 1814 (2016/04/10)
Three new Au(I) complexes of the formula [Au(NHC)(NTf2)] (NHC = N-heterocyclic carbene) bearing bulky and flexible ligands have been synthesised. The ligands studied are IPent, IHept and INon which belong to the 'ITent' ('Tent' for 'tentacular') family of NHC derivatives. The effect of these ligands in gold-promoted transformations has been investigated.
Highly efficient and eco-friendly gold-catalyzed synthesis of homoallylic ketones
Gómez-Suárez, Adrián,Gasperini, Danila,Vummaleti, Sai V.C.,Poater, Albert,Cavallo, Luigi,Nolan, Steven P.
, p. 2701 - 2705 (2014/08/18)
We report a new catalytic protocol for the synthesis of γ,δ-unsaturated carbonyl units from simple starting materials, allylic alcohols and alkynes, via a hydroxalkoxylation/Claisen rearrangement sequence. This new process is more efficient (higher TON an
Reactivity of terminal phenylpentenes in a ruthenium-catalyzed cross-metathesis reaction: Construction of linear bifunctional C-8 alkenes
Stefane, Bogdan,Pozgan, Franc
, p. 633 - 640 (2013/07/26)
In the present study the behavior of 1-functionalized 2-phenylpent-4-enes in the presence of ruthenium-based metathesis catalysts was investigated. The experimental observations revealed that the outcome of the reaction depends very much on the combination of olefinic partners used in the reaction; only certain combinations delivered satisfactory amounts of unsymmetrical cross-metathesis products, i.e., bifunctional C-8 alkenes.
The tandem intermolecular hydroalkoxylation/claisen rearrangement
Ketcham, John M.,Biannic, Berenger,Aponick, Aaron
supporting information, p. 4157 - 4159 (2013/06/04)
The Au(i)-catalyzed intermolecular hydroalkoxylation of alkynes with allylic alcohols to provide allyl vinyl ethers that subsequently undergo Claisen rearrangement is reported. This new cascade reaction strategy facilitates the direct formation of γ,δ-unsaturated ketones from simple starting materials in a single step.
