575433-43-1Relevant academic research and scientific papers
Reversible Structural Transformations of Metal–Organic Frameworks as Artificial Switchable Catalysts for Dynamic Control of Selectively Cyanation Reaction
Huang, Chao,Li, Gaoxiang,Zhang, Lin,Zhang, Yingying,Mi, Liwei,Hou, Hongwei
, p. 10366 - 10374 (2019)
The synthesis of molecular-level artificial switchable catalysts, of which activity in different chemical processes can be switched by controlling different stimuli, has provided a new paradigm to perform mechanical tasks and measurable work. In this work, to obtain highly effective and regioselective artificial switchable catalysts, a hierarchical anion-pillared framework {(H3O)[Cu(CPCDC)(4,4′-bpy)]}n (1; H3CPCDC=9-(4-carboxyphenyl)-9H-carbazole-3,6-dicarboxylic acid, 4,4′-bpy=4,4′-bipyridine), including free [H3O]+ ions as guest molecules, was constructed. Upon dissolve–exchange–crystallization behavior, fascinating reversible structural transformations proceeded between anion framework 1 and neutral 2D stair-stepping framework {[Cu(CPCDC)(4,4′-bpe)]}n (2; 4,4′-bpe=4,4′-vinylenedipyridine). Moreover, frameworks 1 and 2 can act as heterogeneous artificial switchable catalysts to selectively promote the direct cyanation reaction of terminal alkynes and azobisisobutyronitrile. The results indicated that 1 and 2 exhibited excellent selectivity to generate vinyl isobutyronitrile skeletons or propiolonitrile frameworks, respectively, as unique products. Furthermore, indicating paper, GC-MS, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy analysis demonstrated that the reversible structural transformations endowed 1 and 2 with well-defined platforms to stabilize the isobutyronitrile and CN sources through the different catalytic pathways.
Selective α-Deuteration of Cinnamonitriles using D2O as Deuterium Source
Guo, Beibei,de Vries, Johannes G.,Otten, Edwin
, p. 179 - 186 (2021/10/12)
The selective α-deuteration of α,β-unsaturated nitriles using the strong base tBuOK or a metal-ligand cooperative Ru pincer catalyst is described. With D2O as deuterium source and glyme as solvent at 70 °C, tBuOK is an efficient catalyst for deuteration at the α-C(sp2) position of cinnamonitriles, providing access to a broad range of deuterated derivatives in good to excellent yields and with very high levels of deuterium incorporation. While the tBuOK-catalysed protocol does not tolerate base-sensitive functional groups, cinnamonitrile derivatives containing a benzylic bromide or ester moiety were deuterated in excellent yields using Milstein's ruthenium PNN pincer catalyst. Moreover, the activity for H/D exchange of the metal-ligand cooperative Ru catalyst is found to be significantly higher than that of tBuOK, allowing reactions to proceed well even at room temperature. A mechanistic proposal is put forward that involves deprotonation of the cinnamonitrile α-CH position when using tBuOK as catalyst, whereas H/D exchange catalysis with the Ru PNN pincer likely proceeds via (reversible) oxa-Michael addition of D2O. (Figure presented.).
Enantioselective Nickel-Catalyzed Alkyne-Azide Cycloaddition by Dynamic Kinetic Resolution
Liu, En-Chih,Topczewski, Joseph J.
, 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.
An aerobic and green C-H cyanation of terminal alkynes
Si, Yi-Xin,Zhang, Song-Lin,Zhu, Peng-Fei
supporting information, p. 9216 - 9220 (2020/12/03)
This study describes a benign C-H cyanation of terminal alkynes with α-cyanoesters serving as a nontoxic cyanide source. In situ generation of the key copper cyanide intermediate is proposed by a sequence of α-C-H oxidation and copper-mediated β-carbon elimination of α-cyanoesters, releasing the α-ketoester byproduct observed experimentally. The ensuing reaction of copper cyanide with terminal alkynes delivers preferentially cyanoalkynes and surpasses the possible Glaser type dimerization of terminal alkynes or the undesired accumulation of HCN under protic conditions. The presence of the co-oxidant K2S2O8 is crucial to this selectivity, probably by promoting oxidative transmetalation and the resulting formation of the Cu(iii)(acetylide)(CN) intermediate. All the reagents and salts used are commercially available, cheap and nontoxic, avoiding the use of highly toxic cyanide salts typically required in cyanation studies. The scope of this reaction is demonstrated with a set of alkynes and α-cyanoesters. The application of this method to late-stage functionalization of the terminal alkyne group in an estrone derivative is also feasible, showing its practical value for drug design.
Palladium-Catalyzed Nitrile-Assisted C(sp3)-Cl Bond Formation for Synthesis of Dichlorides
He, Dandan,Huang, Liangbin,Li, Jianxiao,Wu, Wanqing,Jiang, Huanfeng
, p. 8308 - 8311 (2019/10/16)
A palladium-catalyzed coupling procedure of alkenes with alkynylnitriles has been demonstrated for the synthesis of dichlorides. The reaction is the first example of nitrile-assisted C(sp3)-Cl formation promoted by coordination of a cyano group with an alkylpalladium(II) complex. The construction of a five-membered cycle intermediate successfully inhibits the β-hydride abstraction, resulting in direct C-Cl bond reductive elimination of alkylpalladium(II) chloride.
Copper metal organic framework (Cu-MOF) catalytic material, and preparation method and application thereof
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Paragraph 0032, (2019/03/06)
The invention provides a copper metal organic framework (Cu-MOF) catalytic material. The catalytic material adopts two organic ligands, namely 9-(4-carboxyphenyl)-9H-carbazole-3,6-dicarboxylic acid (H3CPCDC) and 4,4'-bipyridine (BPY). The catalytic materi
Copper-catalyzed direct cyanation of terminal alkynes with benzoyl cyanide
Du, Yan,Li, Zheng
supporting information, p. 4622 - 4625 (2018/11/27)
Copper-catalyzed direct cyanation of terminal alkynes is achieved using less toxic, stable and easy to handle benzoyl cyanide as a cyanide source and air as an oxidant. This protocol provides a good alternative to the preparation of 3-arylpropiolonitriles
Synthesis of 1-Cyanoalkynes and Their Ruthenium(II)-Catalyzed Cycloaddition with Organic Azides to Afford 4-Cyano-1,2,3-triazoles
Liu, Peiye,Clark, Ronald J.,Zhu, Lei
, p. 5092 - 5103 (2018/05/15)
A new method to convert terminal alkynes under relatively mild conditions to 1-cyanoalkynes using in situ formed cyanogen is described. 1-Cyanoalkynes have a higher reactivity than terminal alkynes in the ruthenium(II)-catalyzed regiospecific azide-alkyne cycloaddition to afford 4-cyano-1,2,3-triazoles. A mechanistic proposal different from the one that terminal alkynes adopt under the same reaction conditions is proposed. This work provides a new and convenient two-step sequence to prepare 4-cyano-1,2,3-triazoles from terminal alkynes and organic azides.
Additive-Controlled Switchable Selectivity from Cyanobenzenes to 2-Alkynylpyridines: Ruthenium(II)-Catalyzed [2+2+2] Cycloadditions of Diynes and Alkynylnitriles
Bhatt, Divya,Patel, Neha,Chowdhury, Hrishikesh,Bharatam, Prasad V.,Goswami, Avijit
supporting information, p. 1876 - 1882 (2018/04/11)
A highly efficient additive-dependent chemoselective protocol for the synthesis of fused cyanoarenes and 2-alkynylpyridines has been developed by the reaction of 1,6-diynes with alkynylnitriles using chloro(pentamethylcyclopentadienyl) (cyclooctadiyne)ruthenium(II) as catalyst in dimethoxyethane (DME). The course of the reaction can be drastically altered simply by adding a catalytic amount of AgOTf as an additive resulting in a comprehensive shift in product formation from cyanoarenes to 2-alkynylpyridines. Theoretical studies clearly indicate that the neutral Ru-complex is responsible for the formation of cyanobenzenes, whereas the in situ generated cationic Ru-complex plays a crucial role in the 2-alkynylpyridines formation. (Figure presented.).
Silver-Mediated Direct C-H Cyanation of Terminal Alkynes with N-Isocyanoiminotriphenylphosphorane
Wang, Hannan,Mi, Pengbing,Zhao, Wanjun,Kumar, Ravi,Bi, Xihe
supporting information, p. 5613 - 5616 (2017/10/25)
A direct cyanation of terminal alkynes for the synthesis of propionitrile derivatives, with the aid of silver salt using water additive, has been achieved. The cyano source used is N-isocyanoiminotriphenylphosphorane, which is nontoxic, safe, and easy to handle. This protocol is characterized by its operational simplicity, high efficiency with excellent yields, broad substrate scope, and greater functional group tolerance.
