51718-85-5Relevant academic research and scientific papers
Enantioselective Nickel-Catalyzed Alkyne-Azide Cycloaddition by Dynamic Kinetic Resolution
Liu, En-Chih,Topczewski, Joseph J.
supporting information, p. 5308 - 5313 (2021/05/04)
The triazole heterocycle has been widely adopted as an isostere for the amide bond. Many native amides are α-chiral, being derived from amino acids. This makes α-N-chiral triazoles attractive building blocks. This report describes the first enantioselective triazole synthesis that proceeds via nickel-catalyzed alkyne-azide cycloaddition (NiAAC). This dynamic kinetic resolution is enabled by a spontaneous [3,3]-sigmatropic rearrangement of the allylic azide. The 1,4,5-trisubstituted triazole products, derived from internal alkynes, are complementary to those commonly obtained by the related CuAAC reaction. Initial mechanistic experiments indicate that the NiAAC reaction proceeds through a monometallic Ni complex, which is distinct from the CuAAC manifold.
Molecular Solar Thermal Batteries through Combination of Magnetic Nanoparticle Catalysts and Tailored Norbornadiene Photoswitches
Lorenz, Patrick,Luchs, Tobias,Hirsch, Andreas
supporting information, p. 4993 - 5002 (2021/02/26)
Cobalt catalysts are immobilized on the surface of iron oxide nanoparticles for the preparation of highly active quasi-homogeneous catalysts toward an efficient release of photochemically stored energy in norbornadiene-based photoswitches. The facile sepa
Gold-catalyzed partial hydrogenation of activated alkynes mediated by triphenylphosphine
Cocoletzi-Xochitiotzi, Ana Patricia,Hernández-Hernández, Miguel,Medina-Mercado, Ignacio,Jiménez-Martínez, Williams De Jesús,Mastranzo, Virginia Maricela,Porcel, Susana
supporting information, p. 2379 - 2386 (2020/08/19)
Gold(I) can exhibit a cooperative effect with triphenylphosphine, accelerating the triphenylphosphine-mediated partial hydrogenation of activated alkynes. In this protocol, 3-arylpropiolates are selectively reduced to the Z -isomer when the aryl ring bears an electron-donor substituent, whereas 3-arylpropynones are reduced to the E-isomers.
Consecutive Three-Component Coupling-Addition Synthesis of β-Amino Enoates and 3-Hydroxypyrazoles via Ethyl 3-Arylpropiolates
Niedballa, Jonas,Reiss, Guido J.,Müller, Thomas J. J.
supporting information, p. 5019 - 5024 (2020/07/24)
Two consecutive three-component syntheses furnishing β-amino enoates or 3-hydroxypyrazoles based upon the Sonogashira alkynylation of aryl iodides and ethyl propiolate were established in mostly excellent yields. The ethyl 3-arylpropiolate intermediates are Michael systems which are suited for concatenation with conjugate addition or cyclocondensation giving access to libraries of 21 different β-amino enoates and 17 different 3-hydroxypyrazoles. The rotational barrier of β-pyrrolidino enoates was assessed by studying the coalescence of pyrrolidinyl protons in VT-NMR spectra of electronically different substituted derivatives showing that the electronic substituent effect on the aryl group does not affect the height of the rotational barrier. This indicates that the substituents are essentially oriented orthogonally to the plane of the β-pyrrolidino enoates.
Selective synthesis of trisubstituted pyrroles through the reactions of alkynyl Fischer carbene complexes with oxazolones
López, Julio,Velazco-Cabral, Iván,Rodríguez-DeLeón, Eloy,Villegas Gómez, Clarisa,Delgado, Francisco,Tamariz, Joaquín,Arrieta, Ana,Cossío, Fernando P.,Vázquez, Miguel A.
supporting information, p. 538 - 550 (2020/01/30)
An efficient and simple synthesis of novel trisubstituted 1H-pyrroles 4a-qvia 1,3-dipolar cycloaddition of Δ3-trifluoromethyloxazolones 2a-d with both chromium and tungsten alkynyl Fischer carbene complexes (1a-h) is described. An unexpected and unreported -CF3 group elimination process was observed in the pyrrole structure. Our experimental and theoretical data suggested that the metal fragment may be responsible for this phenomenon. The dipolar cycloaddition proceeded efficiently to produce a single regioisomer, which was unambiguously established through NMR and single-crystal X-ray diffraction studies. Nevertheless, the reaction of alkynyl carbenes bearing an α,β,γ,δ-unsaturated moiety with excess oxazolone 2a produced a polycyclic compound 6 speculatively formed through a cascade reaction involving 1,6-, 1,4- and 1,2-nucleophilic addition steps.
Copper-catalyzed enantioselective conjugate reduction of α,β-unsaturated esters with chiral phenol–carbene ligands
Mimura, Shohei,Mizushima, Sho,Sawamura, Masaya,Shimizu, Yohei
, p. 537 - 543 (2020/05/14)
A chiral phenol–NHC ligand enabled the copper-catalyzed enantioselective conjugate reduction of α,β-unsaturated esters. The phenol moiety of the chiral NHC ligand played a critical role in producing the enantiomerically enriched products. The catalyst worked well for various (Z)-isomer substrates. Opposite enantiomers were obtained from (Z)- and (E)-isomers, with a higher enantiomeric excess from the (Z)-isomer.
A Parallel Approach to 7-(Hetero)arylpyrazolo[1,5- a]pyrimidin-5-ones
Schmitt, Daniel C.,Niljianskul, Nootaree,Sach, Neal W.,Trujillo, John I.
supporting information, p. 256 - 260 (2018/05/24)
A modular, two-pot assembly of 7-arylpyrazolo[1,5-a]pyrimidones from aryl/heteroaryl halides and aminopyrazoles in library format was developed. Sonogashira coupling of aryl bromides with triethyl orthopropiolate, followed by in situ orthoester hydrolysis
Rhodium(III)-Catalyzed Redox-Neutral Cascade [3 + 2] Annulation of N-Phenoxyacetamides with Propiolates via C-H Functionalization/Isomerization/Lactonization
Pan, Jin-Long,Chen, Chao,Hao, Yu,Liu, Chang,Bai, He-Yuan,Ding, Jun,Zhang, Shu-Yu,Wang, Li-Ren,Xie, Peipei,Xia, Yuanzhi
supporting information, p. 7131 - 7136 (2018/12/14)
A Rh(III)-catalyzed cascade [3 + 2] annulation of N-phenoxyacetamides with propiolates under mild conditions using the internal oxidative O-N bond as the directing group has been achieved. This catalytic system provides a regio- and stereoselective access to benzofuran-2(3H)-ones bearing exocyclic enamino motifs with exclusive Z configuration selectivity, acceptable to good yields and good functional group compatibility. Mechanistic investigations by experimental and density functional theory studies suggest that a consecutive process of C-H functionalization/isomerization/lactonization is likely to be involved in the reaction.
Understanding the mechanism of transition metal-free: Anti addition to alkynes: The selenoboration case
García-López, Diego,Civit, Marc G.,Vogels, Christopher M.,Ricart, Josep M.,Westcott, Stephen A.,Fernández, Elena,Carbó, Jorge J.
, p. 3617 - 3628 (2018/07/29)
The stereoselective anti-addition of selenoboranes to α,β-acetylenic esters and amides was achieved in a transition metal-free context using catalytic amounts of PCy3. The reaction provides anti-3,4-selenoboration with concomitant delivery of α-vinyl selenides by protodeboronation with MeOH. Interestingly, in the absence of phosphine the selenoboration switches towards the formation of β-vinyl selenides. Theoretical calculations rationalize the regio- and stereoselectivity of the reaction by discovering a new mechanism for the anti-3,4-selenoboration. While the selenoborane is activated via the "push-pull" effect of B, the phosphine interacts with the β position of the alkynoate switching the polarity of the triple bond and favoring 1,3-selenoboration which provides the α-addition of the selenyl group. Then, the autocatalytic action of a second selenoborane reagent, which coordinates to the phosphorus ylide intermediate, determines the stereoselectivity and completes the catalytic process. Finally, the comparison of selenoborane reagents with diboranes and silaboranes, which have exhibited analogous reactivity, shows that the selenium moiety has a larger nucleophilic character favoring the performance of the reaction under mild conditions.
Triazole-imidazole (TA-IM) derivatives as ultrafast fluorescent probes for selective Ag+ detection
Lai, Qi,Liu, Qing,He, Ying,Zhao, Kai,Wei, Chiyu,Wojtas, Lukasz,Shi, Xiaodong,Song, Zhiguang
supporting information, p. 7801 - 7805 (2018/11/21)
1,2,3-Triazole-imidazole derivatives (TA-IM) were prepared as fluorescent probes for silver ion detection. The design principle is the incorporation of an intramolecular H-bond between the imidazole and triazole moiety that enables a co-planar conformation to achieve fluorescence emission in the UV-blue range. Screening of different metal ions revealed excellent binding affinity of this new class of compounds toward silver ions in aqueous solution. The novel probe provided ultrafast detection (30 s) even for a very low concentration of silver ions (in the nM range) with good linear correlation, making it a practical sensor for detection of silver ions.
