20432-26-2Relevant articles and documents
The synergistic copper/ppm Pd-catalyzed hydrocarboxylation of alkynes with formic acid as a CO surrogate as well as a hydrogen source: An alternative indirect utilization of CO2
Chen, Kai-Hong,He, Liang-Nian,Qiu, Li-Qi,Xia, Shu-Mei,Yang, Zhi-Wen,Yao, Xiang-Yang
supporting information, p. 8089 - 8095 (2021/11/01)
An unprecedented strategy has been developed involving the earth-abundant Cu-catalyzed hydrocarboxylation of alkynes with HCOOH to (E)-acrylic derivatives with high regio- and stereoselectivity via synergistic effects with ppm levels of a Pd catalyst. Both symmetrical and unsymmetrical alkynes bearing various functional groups were successfully hydrocarboxylated with HCOOH, and the modification of a pharmaceutical molecule exemplified the practicability of this process. This protocol employs HCOOH as both a CO surrogate and hydrogen donor with 100% atom economy and it can be viewed as an alternative approach for indirect CO2 utilization. Mechanistic investigations indicate a Cu/ppm Pd cooperative catalysis mechanism via alkenylcopper species as potential intermediates formed from Cu-hydride active catalytic species with HCOOH as a hydrogen source. This bimetallic system involving inexpensive Cu and trace Pd provides a reliable and efficient hydrocarboxylation method to access industrially useful acrylic derivatives with HCOOH as a hydrogen source, and it provides novel clues for optimizing other Cu-H-related co-catalytic systems.
Method for preparing alpha, beta-unsaturated carboxylic acid compound
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Paragraph 0103-0110; 0511-0518, (2021/05/05)
The invention discloses a method for preparing an alpha, beta-unsaturated carboxylic acid compound, which comprises the following steps: 1) in an atmosphere containing carbon dioxide, heating and reacting a mixture containing hydrosilane and a copper catalyst to obtain a system I; and 2) adding a raw material containing alkyne and a nickel catalyst into the system I in the step 1), and heating to react. The method has the advantages of simple, easily available, cheap and stable raw materials, common, easily available and stable catalyst, mild reaction conditions, simple post-treatment, high yield and the like.
Water-initiated hydrocarboxylation of terminal alkynes with CO2and hydrosilane
Wang, Meng-Meng,Lu, Sheng-Mei,Paridala, Kumaraswamy,Li, Can
supporting information, p. 1230 - 1233 (2021/02/09)
This work discloses a Cu(ii)-Ni(ii) catalyzed tandem hydrocarboxylation of alkynes with polysilylformate formed from CO2and polymethylhydrosiloxane that affords α,β-unsaturated carboxylic acids with up to 93% yield. Mechanistic studies indicate that polysilylformate functions as a source of CO and polysilanol. Besides, a catalytic amount of water is found to be critical to the reaction, which hydrolyzes polysilylformate to formic acid that induces the formation of Ni-H active species, thereby initiating the catalytic cycle.
Electrochemical oxidative: Z -selective C(sp2)-H chlorination of acrylamides
Coles, Simon J.,Hareram, Mishra Deepak,Harnedy, James,Morrill, Louis C.,Tizzard, Graham J.
supporting information, p. 12643 - 12646 (2021/12/07)
An electrochemical method for the oxidative Z-selective C(sp2)-H chlorination of acrylamides has been developed. This catalyst and organic oxidant free method is applicable across various substituted tertiary acrylamides, and provides access to a broad range of synthetically useful Z-β-chloroacrylamides in good yields (22 examples, 73% average yield). The orthogonal derivatization of the products was demonstrated through chemoselective transformations and the electrochemical process was performed on gram scale in flow.
Ligand-controlled divergent dehydrogenative reactions of carboxylic acids via C–H activation
Wang, Zhen,Hu, Liang,Chekshin, Nikita,Zhuang, Zhe,Qian, Shaoqun,Qiao, Jennifer X.,Yu, Jin-Quan
, p. 1281 - 1285 (2021/12/10)
Dehydrogenative transformations of alkyl chains to alkenes through methylene carbon-hydrogen (C–H) activation remain a substantial challenge. We report two classes of pyridine-pyridone ligands that enable divergent dehydrogenation reactions through palladium-catalyzed b-methylene C–H activation of carboxylic acids, leading to the direct syntheses of a,b-unsaturated carboxylic acids or g-alkylidene butenolides. The directed nature of this pair of reactions allows chemoselective dehydrogenation of carboxylic acids in the presence of other enolizable functionalities such as ketones, providing chemoselectivity that is not possible by means of existing carbonyl desaturation protocols. Product inhibition is overcome through ligand-promoted preferential activation of C(sp3)–H bonds rather than C(sp2)–H bonds or a sequence of dehydrogenation and vinyl C–H alkynylation. The dehydrogenation reaction is compatible with molecular oxygen as the terminal oxidant.
Access to α,β-unsaturated carboxylic acids through water-soluble palladium catalyzed hydroxycarbonylation of alkynes using water as the solvent
Gao, Mingjie,Jia, Xiaofei,Lv, Jinhe,Ren, Xinyi,Song, Jiaxin,Xie, Congxia,Zhang, Jinrong,Zhang, Kai,Zhao, Jinyu,Zhou, Ziqin,Zong, Lingbo
, p. 4708 - 4713 (2021/07/26)
A sulfoxantphos modified palladium-catalyzed synthesis of α,β-unsaturated carboxylic acids from alkynes with CO and H2O was described. The atom-economic hydroxycarbonylation of various symmetrical and unsymmetrical alkynes can be achieved with chemo-, stereo-, and regioselectivity, affording the corresponding carboxylic acids in good to excellent yields. Using water as the reaction solvent, the water-soluble palladium catalyst was easily separated from the product and could be reused for 5 cycles.
Palladium-Catalyzed Highly Regioselective Hydrocarboxylation of Alkynes with Carbon Dioxide
Chen, Pengquan,Cheng, Ruixiang,Jiang, Huanfeng,Lei, Ming,Lou, Hongming,Qi, Chaorong,Shi, Fuxing,Wang, Lu,Wu, Wanqing,Xiong, Wenfang,Zhu, Baiyao
, p. 7968 - 7978 (2020/08/21)
A Pd-catalyzed highly regioselective hydrocarboxylation of alkynes with carbon dioxide has been established. By the combination of Pd(PPh3)4 and 2,2′-bis(diphenylphosphino)-1,1′-binaphthalene (binap), a variety of functionalized alkynes, including aryl alkynes, aliphatic alkynes, propargylamines, and propargyl ethers, could be leveraged to provide a wide array of α-acrylic acids in high yields with high regioselectivity under mild reaction conditions. Experimental and DFT mechanistic studies revealed that this reaction proceeded via the cyclopalladation process of alkynes and carbon dioxide in the presence of binap to generate a five-membered palladalactone intermediate and enabled the formation of Markovnikov adducts. Moreover, this strategy provided an effective method for the late-stage functionalization of alkyne-containing complicated molecules, including natural products and pharmaceuticals.
Visible-Light-Mediated Heterocycle Functionalization via Geometrically Interrupted [2+2] Cycloaddition
Alegre-Requena, Juan V.,Mekereeya, Aroonroj,Paton, Robert S.,Popescu, Mihai V.,Smith, Martin D.
supporting information, p. 23020 - 23024 (2020/10/15)
The [2+2] photocycloaddition is the most valuable and intensively investigated photochemical process. Here we demonstrate that irradiation of N-acryloyl heterocycles with blue LED light (440 nm) in the presence of an IrIII complex leads to efficient and high yielding fused γ-lactam formation across a range of substituted heterocycles. Quantum calculations show that the reaction proceeds via cyclization in the triplet excited state to yield a 1,4-diradical; intersystem crossing leads preferentially to the closed shell singlet zwitterion. This is geometrically restricted from undergoing recombination to yield a cyclobutane by the planarity of the amide substituent. A prototropic shift leads to the observed bicyclic products in what can be viewed as an interrupted [2+2] cycloaddition.
Caesium fluoride-mediated hydrocarboxylation of alkenes and allenes: Scope and mechanistic insights
Gevorgyan, Ashot,Obst, Marc F.,Guttormsen, Yngve,Maseras, Feliu,Hopmann, Kathrin H.,Bayer, Annette
, p. 10072 - 10078 (2019/11/14)
A caesium fluoride-mediated hydrocarboxylation of olefins is disclosed that does not rely on precious transition metal catalysts and ligands. The reaction occurs at atmospheric pressures of CO2 in the presence of 9-BBN as a stoichiometric reductant. Stilbenes, β-substituted styrenes and allenes could be carboxylated in good yields. The developed methodology can be used for preparation of commercial drugs as well as for gram scale hydrocarboxylation. Computational studies indicate that the reaction occurs via formation of an organocaesium intermediate.
Visible-Light-Driven alkyne hydro-/carbocarboxylation using CO2 via iridium/cobalt dual catalysis for divergent heterocycle synthesis
Hou, Jing,Ee, Aloysius,Feng, Wei,Xu, Jin-Hui,Zhao, Yu,Wu, Jie
supporting information, p. 5257 - 5263 (2018/04/24)
We present herein the first visible-light-driven hydrocarboxylation as well as carbocarboxylation of alkynes using CO2 via an iridium/cobalt dual catalysis. Such transformations provide access to various pharmaceutically important heterocycles in a one-pot procedure from readily available alkynes. Coumarins, 2-quinolones, and 2-benzoxepinones were directly accessed through a one-pot alkyne hydrocarboxylation/alkene isomerization/cyclization sequence in which the Ir photocatalyst serves a dual role to promote single-electron transfer in alkyne hydrocarboxylation and energy transfer in the subsequent alkene isomerization. Moreover, an unprecedented cobalt carboxylation/acyl migration cascade enables alkyne difunctionalization to introduce γ-hydroxybutenolides with high efficiency. We expect that this cascade strategy will inspire new perspectives for alkyne and alkene difunctionalization.
