10273-90-2Relevant academic research and scientific papers
Orthogonal cross-coupling through intermolecular metathesis of unstrained C(aryl)–C(aryl) single bonds
Zhu, Jun,Zhang, Rui,Dong, Guangbin
, p. 836 - 842 (2021)
While metathesis reactions involving carbon–carbon double bonds, namely olefin metathesis, have been well established with broad utility in organic synthesis and materials science, direct metathesis of kinetically less accessible C–C single bonds is extremely rare. Here we report a ruthenium-catalysed reversible C–C single-bond metathesis reaction that allows redox- and pH-neutral biaryl synthesis. Assisted by directing groups, unstrained homo-biaryl compounds undergo aryl exchanges to generate cross-biaryl products, catalysed by a well-defined air-stable ruthenium(II) complex. Functional groups reactive under typical cross-coupling reactions, such as halogen, silyl and boronate moieties, are compatible under the metathesis conditions. Mechanistic studies disclose an intriguing ‘olefin-metathesis-like’ pathway that involves an unexpected heptacoordinated, 18-electron closed-shell intermediate. The distinct reaction mode discovered here is expected to inspire the development of more general C–C single-bond metathesis and orthogonal cross-coupling reactions. [Figure not available: see fulltext.].
Meta-dehydrogenative alkylation of arenes with ethers, ketones, and esters catalyzed by ruthenium
Li, Gang,Gao, Yuan,Jia, Chunqi,Wang, Shichong,Yan, Bingxu,Fang, Yu,Yang, Suling
, p. 8758 - 8763 (2020)
A meta-dehydrogenative alkylation of arenes with cyclic ethers, ketones, and esters catalyzed by ruthenium is achieved in the presence of a di-tert-butyl peroxide (DTBP) oxidant. Interestingly, when quinoline and isoquinoline are employed as the directing group, or a chain ether as alkylation reagent, the system produces Minisci reaction products. Mechanistic study indicates that meta-dehydrogenative alkylation is a radical process initiated by DTBP with the assistance of a CAr-Ru bond ortho/para-directing effect.
Multicomponent [5 + 2] cycloaddition reaction for the synthesis of 1,4-diazepines: Isolation and reactivity of azomethine ylides
Lee, Dong Jin,Han, Hong Sik,Shin, Jinhwan,Yoo, Eun Jeong
, p. 11606 - 11609 (2014)
Air-stable azomethine ylides with an unusual pattern of charge distribution were efficiently prepared via the rhodium-catalyzed reaction between pyridines and 1-sulfonyl-1,2,3-triazoles. This reaction allowed for the first example of the catalytic multicomponent [5 + 2] cycloaddition reactions, thus resulting in the formation of biologically active 1,4-diazepine compounds.
Bis[ N, N ′-(2-indanolyl)]-1,5-diazacyclooctane as Unique Metal Ligand: Self-Assembly of Palladium Nanoparticles and Catalytic Reactivity on C-C Bond Formation
Fujiki, Katsumasa,Tanaka, Katsunori
, p. 1097 - 1104 (2018)
A previously unreported 1,5-diazacyclooctane-palladium(II) complex was synthesized using bis[ N, N ′-(2-indanolyl)]-1,5-diazacyclooctane, which was readily prepared via a novel [4+4] homocyclization of the unsaturated imine intermediate generated from acrolein and 1-amino-2-indanol. Interestingly, the 1,5-diazacyclooctane-palladium(II) complex self-assembled to form palladium nanoparticles. This approach readily provided palladium nanoparticles simply by heating a mixture of palladium(II) acetate and bis[ N, N ′-(2-indanolyl)]-1,4-diazacyclooctane in dichloroethane at mild temperatures. The 1,5-diazacyclooctane-derivative-palladium nanoparticles were successfully deployed in synthetic applications as a heterogeneous catalyst, facilitating Suzuki coupling and a challenging C-C bond formation via C(sp 3)-H activation under low catalyst loading conditions.
Cp2Fe(PR2)2PdCl2 (R = i-Pr, t-Bu) complexes as air-stable catalysts for challenging Suzuki coupling reactions
Colacot, Thomas J.,Shea, Helene A.
, p. 3731 - 3734 (2004)
(Chemical Equation Presented) The use of Cp2Fe(PR 2)2PdCl2 (R = i-Pr and t-Bu) in Suzuki coupling reactions were illustrated using a high throughput screening approach. The di-tbpfPdCl2 catalyst was shown to be the more active catalyst for unactivated and sterically challenging aryl chlorides. Comparison studies using the commercial catalysts dppfPdCl2, (Ph3P) 2PdCl2, (Cy3P)2PdCl2, DPEPhosPdCl2, dppbPdCl2, dppePdCl2, Pd(t-Bu3P)2, and [Pd-(μ-Br)(t-Bu3P)] 2 were also done for selected cases to demonstrate the superior activities of di-tbpfPdCl2 and di-isoppfPdCl2.
Enabling Catalytic Arene C-H Amidomethylation via Bis(tosylamido)methane as a Sustainable Formaldimine Releaser
Li, Zhong-Yuan,Chaminda Lakmal, Hetti Handi,Cui, Xin
, p. 3735 - 3740 (2019)
Addition of catalytic arene C-H to formaldimines has been enabled by Ru(II)-catalyzed amidomethylation with bis(tosylamido)methane as a catalytic formaldimine releaser. The new process provides an atom-efficient and sustainable solution to address the challenges of formaldimines in this type of transformation. Furthermore, new synthetic routes based on this catalytic system have been developed for step-efficient access to N-heterotricyclic core structures that are pharmaceutically relevant.
A Graphene Oxide Nanosheet Supported NHC-Palladium Complex as a Highly Efficient and Recyclable Suzuki Coupling Catalyst
Qian, Yingjie,So, Jaeil,Jung, Sang-Yung,Hwang, Sosan,Jin, Myung-Jong,Shim, Sang Eun
, p. 2287 - 2292 (2019)
A practical heterogeneous catalyst was prepared by anchoring a triazine-tethered N-heterocyclic carbene (NHC)-palladium complex on the surface of graphene oxide (GO) nanosheets. The immobilized complex was characterized by X-ray photoelectron spectroscopy, field-emission transmission electron microscopy, energy-dispersive X-ray spectroscopy, and surface area analysis. It proved to be a highly active and durable heterogeneous catalyst for Suzuki coupling reactions. At room temperature, the use of this catalyst enabled the preparation of various biaryls and heterobiaryls in short reaction times. The catalytic system could be recycled at least 10 times with almost consistent activity. The results reveal that the stable palladium complex is strongly anchored on the surface of GO nanosheets. Interestingly, an open planar network of the GO nanosheet support plays a role during the catalytic process in enhancing the catalytic activity.
Palladium-Catalyzed Electrochemical C-H Alkylation of Arenes
Yang, Qi-Liang,Li, Chuan-Zeng,Zhang, Liang-Wei,Li, Yu-Yan,Tong, Xiaofeng,Wu, Xin-Yan,Mei, Tian-Sheng
supporting information, p. 1208 - 1212 (2018/10/20)
Palladium-catalyzed electrochemical C-H functionalization reactions have emerged as attractive tools for organic synthesis. This process offers an alternative to conventional methods that require harsh chemical oxidants. However, this electrolysis requires divided cells to avoid catalyst deactivation by cathodic reduction. Herein, we report the first example of palladium-catalyzed electrochemical C-H alkylation of arenes using undivided electrochemical cells in water, thereby providing a practical solution for the introduction of alkyl groups into arenes.
A palladium complex confined in a thiadiazole-functionalized porous conjugated polymer for the Suzuki-Miyaura coupling reaction
Qian, Yingjie,Jeong, Sang Yung,Baeck, Sung-Hyeon,Jin, Myung-Jong,Shim, Sang Eun
, p. 33563 - 33571 (2019/11/13)
Porous organic polymers (POPs) with well-distributed and tunable functional groups acting as ligands for specific reactions are promising supports for confining useful novel metals such as Pd, Au, and Pd. Herein, a thiadiazole-containing POP has been successfully synthesized and used for immobilizing Pd species. Pd immobilized inside the micropores (2.3 nm) of the POP material is easily prepared owing to a large amount of the strong anchoring group, thiadiazole, which is intrinsically distributed in the as-prepared POP. The rigid thiadiazole-containing polymer can stabilize the central metal rather than poisoning it. The as-prepared catalyst shows excellent catalytic activity in Suzuki-Miyaura coupling reactions under mild reaction conditions and low catalyst loading. Importantly, the intrinsically distributed thiadiazole ligands can stabilize the Pd moiety, preventing aggregation and leaching, and afford excellent catalytic lifetimes. Consequently, the catalyst can be reused 10 times without a significant loss of its catalytic activity.
Ruthenium-Catalyzed Reductive Cleavage of Unstrained Aryl-Aryl Bonds: Reaction Development and Mechanistic Study
Zhu, Jun,Chen, Peng-hao,Lu, Gang,Liu, Peng,Dong, Guangbin
supporting information, p. 18630 - 18640 (2019/11/21)
Cleavage of carbon-carbon bonds has been found in some important industrial processes, for example, petroleum cracking, and has inspired development of numerous synthetic methods. However, nonpolar unstrained C(aryl)-C(aryl) bonds remain one of the toughest bonds to be activated. As a detailed study of a fundamental reaction mode, here a full story is described about our development of a Ru-catalyzed reductive cleavage of unstrained C(aryl)-C(aryl) bonds. A wide range of biaryl compounds that contain directing groups (DGs) at 2,2′ positions can serve as effective substrates. Various heterocycles, such as pyridine, quinoline, pyrimidine, and pyrazole, can be employed as DGs. Besides hydrogen gas, other reagents, such as Hantzsch ester, silanes, and alcohols, can be employed as terminal reductants. The reaction is pH neutral and free of oxidants; thus a number of functional groups are tolerated. Notably, a one-pot C-C activation/C-C coupling has been realized. Computational and experimental mechanistic studies indicate that the reaction involves a ruthenium(II) monohydride-mediated C(aryl)-C(aryl) activation and the resting state of the catalyst is a η4-coordinated ruthenium(II) dichloride complex, which could inspire development of other transformations based on this reaction mode.
