935-02-4Relevant articles and documents
Cyanide-Free Cyanation of sp2 and sp-Carbon Atoms by an Oxazole-Based Masked CN Source Using Flow Microreactors
Sharma, Brijesh M.,Nikam, Arun V.,Lahore, Santosh,Ahn, Gwang-Noh,Kim, Dong-Pyo
supporting information, (2022/02/25)
This work reports a cyanide-free continuous-flow process for cyanation of sp2 and sp carbons to synthesize aryl, vinyl and acetylenic nitriles from (5-methyl-2-phenyloxazol-4-yl) boronic acid [OxBA] reagent as a sole source of carbon-bound mask
AlBr3-Promoted stereoselective anti-hydroarylation of the acetylene bond in 3-arylpropynenitriles by electron-rich arenes: Synthesis of 3,3-diarylpropenenitriles
Gorbunova, Yelizaveta,Ryabukhin, Dmitry S.,Vasilyev, Aleksander V.
, p. 2663 - 2667 (2021/11/30)
Reactions of 3-arylpropynenitriles (ArC≡CCN) with electron-rich arenes (Ar'H, benzene and its polymethylated derivatives) under the action of aluminum bromide (AlBr3, 6 equiv) at room temperature for 0.5-2 h result in the stereoselective formation of 3,3-
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.
Chemo- And regioselective click reactions through nickel-catalyzed azide-alkyne cycloaddition
Baek, Seung-Yeol,Baik, Mu-Hyun,Choe, Wonyoung,Hong, Sung You,Jeon, Ji Hwan,Jeong, Seo Yeong,Kim, Woo Gyum,Nam, Dongsik
supporting information, p. 3374 - 3381 (2020/05/14)
Metal-catalyzed cycloaddition is an expeditious synthetic route to functionalized heterocyclic frameworks. However, achieving reactivity-controlled metal-catalyzed azide-alkyne cycloadditions from competing internal alkynes has been challenging. Herein, we report a nickel-catalyzed [3 + 2] cycloaddition of unsymmetrical alkynes with organic azides to afford functionalized 1,2,3-triazoles with excellent regio- and chemoselectivity control. Terminal alkynes and cyanoalkynes afford 1,5-disubstituted triazoles and 1,4,5-trisubstituted triazoles bearing a 4-cyano substituent, respectively. Thioalkynes and ynamides exhibit inverse regioselectivity compared with terminal alkynes and cyanoalkynes, affording 1,4,5-trisubstituted triazoles with 5-thiol and 5-amide substituents, respectively. Density functional theory calculations are performed for the elucidation of the reaction mechanism. The computed mechanism suggests that a nickellacyclopropene intermediate is generated by the oxidative addition of the alkyne substrate to the Ni(0)-Xantphos catalyst, and the subsequent C-N coupling of this intermediate with an azide is responsible for the chemo- and regioselectivity.
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.
SO2F2-Mediated one-pot cascade process for transformation of aldehydes (RCHO) to cyanamides (RNHCN)
Ding, Chengrong,Ge, Shuting,Wei, Junjie,Zhang, Guofu,Zhao, Yiyong
, p. 17288 - 17292 (2020/05/18)
A simple, mild and practical cascade process for the direct conversion of aldehydes to cyanamides was developed featuring a wide substrate scope and great functional group tolerability. This method allows for transformations of readily available, inexpensive, and abundant aldehydes to highly valuable cyanamides in a pot, atom, and step-economical manner with a green nitrogen source. This protocol will serve as a robust tool for the installation of the cyanamide moiety in various complicated molecules.
Palladium-Catalyzed Nitrile-Assisted C(sp3)-Cl Bond Formation for Synthesis of Dichlorides
He, Dandan,Huang, Liangbin,Li, Jianxiao,Wu, Wanqing,Jiang, Huanfeng
supporting information, 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.
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
supporting information, p. 10366 - 10374 (2019/07/18)
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.
Copper metal organic framework (Cu-MOF) catalytic material, and preparation method and application thereof
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Paragraph 0031, (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
Water as a Hydrogenating Agent: Stereodivergent Pd-Catalyzed Semihydrogenation of Alkynes
Zhao, Chuan-Qi,Chen, Yue-Gang,Qiu, Hui,Wei, Lei,Fang, Ping,Mei, Tian-Sheng
supporting information, p. 1412 - 1416 (2019/03/07)
Palladium-catalyzed transfer semihydrogenation of alkynes using H2O as the hydrogen source and Mn as the reducing reagent is developed, affording cis- and trans-alkenes selectively under mild conditions. In addition, this method provides an efficient way to access various cis-1,2-dideuterioalkenes and trans-1,2-dideuterioalkenes by using D2O instead of H2O.
