40133-23-1Relevant academic research and scientific papers
Pyrazole-Mediated C-H Functionalization of Arene and Heteroarenes for Aryl-(Hetero)aryl Cross-Coupling Reactions
Kundu, Abhishek,Dey, Dhananjay,Pal, Subhankar,Adhikari, Debashis
, p. 15665 - 15673 (2021/11/16)
Herein we introduce a transition-metal-free protocol that involves a commercially available, inexpensive pyrazole molecule to conduct C-C cross-coupling reactions at room temperature via a radical pathway. Using this method, an aryldiazonium salt has been coupled to a wide range of arenes and heteroarenes including benzene, mesitylene, thiophene, furan, benzoxazole to result the corresponding biaryl products. The full reaction mechanism is elucidated along with the crystallographic probation of an active initiator species. A potassium-stabilized deprotonated pyrazole steers single-electron transfer to the substrate and behaves as an initiator for the reaction.
Synthesis of a Cellulosic Pd(salen)-Type Catalytic Complex as a Green and Recyclable Catalyst for Cross-Coupling Reactions
Sun, Peng,Yang, Jiaojiao,Chen, Chunxia,Xie, Kaijun,Peng, Jinsong
, p. 2900 - 2910 (2020/03/31)
Abstract: A green recyclable cellulose-supported Pd(salen)-type catalyst was synthesized through sequential three steps: chlorination with thionyl chloride, modification by ethylenediamine, and the formation of Schiff base with salicylaldehyde to immobilize palladium chloride through multiple binding sites. This novel heterogeneous cellulosic Pd(salen)-type catalytic complex was fully characterized by FT-IR, SEM, TEM, XPS, ICP-AES and TG. The traditional cross-coupling chemistry, such as Suzuki, Heck, Sonogashira, Buchwald–Hartwig amination and etherification, was then investigated in the presence of the above cellulose-palladium nanoparticle. Studies have shown that the synthesized catalyst shows high activity and efficiency for all types of transformations, providing the corresponding carbon–carbon or carbon–heteroatom coupling products in a general and mild manner. Furthermore, the catalyst demonstrates high to excellent yields and is easily recycled by simple filtration for up to twelve cycles without any significant loss of catalytic activity. Graphic Abstract: [Figure not available: see fulltext.]
Transition-Metal-Free Synthesis of Heterobiaryls through 1,2-Migration of Boronate Complex
Paul, Swagata,Das, Kanak Kanti,Manna, Samir,Panda, Santanu
supporting information, p. 1922 - 1927 (2020/02/04)
The synthesis of a diverse range of heterobiaryls has been achieved by a transition-metal-free sp2–sp2 cross-coupling strategy using lithiated heterocycle, aryl or heteroaryl boronic ester and an electrophilic halogen source. The construction of heterobiaryls was carried out through electrophilic activation of the aryl–heteroaryl boronate complex, which triggered 1,2-migration from boron to the carbon atom. Subsequent oxidation of the intermediate boronic ester afforded heterobiaryls in good yield. A comprehensive 11B NMR study has been conducted to support the mechanism. The cross coupling between two nucleophilic cross coupling partners without transition metals reveals a reliable manifold to procure heterobiaryls in good yields. Various heterocycles like furan, thiophene, benzofuran, benzothiophene, and indole are well tolerated. Finally, we have successfully demonstrated the gram scale synthesis of the intermediates for an anticancer drug and OLED material using our methodology.
1-Aryltriazenes in the Suzuki, Heck, and Sonogashira Reactions in Imidazolium-ILs, with [BMIM(SO3H)][OTf] or Sc(OTf)3 as Promoter, and Pd(OAc)2 or NiCl2·glyme as Catalyst
Sutar, Suraj M.,Savanur, Hemantkumar M.,Malunavar, Shruti S.,Prabhala, Pavankumar,Kalkhambkar, Rajesh G.,Laali, Kenneth K.
supporting information, p. 6088 - 6093 (2019/09/17)
1-Aryltriazenes, the protected and more stable form of aryl-diazonium species, can be conveniently unmasked with Br?nsted acidic-IL or Sc(OTf)3 and coupled with a host of aryl/heteroaryl boronic acids, styrenes, and aryl/alkyl acetylenes in the Suzuki, Heck and Sonogashira reactions in one-pot and in respectable isolated yields, by using palladium or nickel catalyst in readily available imidazolium ILs as solvent, under mild conditions. The scope of these reactions are explored, and the potential for recovery/reuse of the IL solvent is also addressed.
Phenalenyl Based Aluminum Compound for Catalytic C-H Arylation of Arene and Heteroarenes at Room Temperature
Vardhanapu, Pavan K.,Ahmed, Jasimuddin,Jose, Anex,Shaw, Bikash Kumar,Sen, Tamal K.,Mathews, Amita A.,Mandal, Swadhin K.
, p. 289 - 299 (2019/01/10)
Main group metal based catalysis has been considered to be a cost-effective alternative way to the transition metal based catalysis, due to the high abundance of main group metals in the Earth's crust. Among the main group metals, aluminum is the most abundant (7-8%) in the Earth's crust, making the development of aluminum based catalysts very attractive. So far, aluminum based compounds have been popularly used as Lewis acids in a variety of organic reactions, but chemical transformation demanding a redox based process has never utilized an Al(III) complex as a catalyst. Herein, we tuned the redox noninnocence behavior of a phenalenyl ligand by coupling with Al(III) ion, which subsequently can store the electron upon reduction with K to carry out direct C-H arylation of heteroarenes/mesitylene at ambient temperature. A mechanistic investigation revealed that a three-electron reduced phenalenyl based triradical aluminum(III) complex plays the key role in such catalysis. The electronic structure of the catalytically active triradical species has been probed using EPR spectroscopy, magnetic susceptibility measurements, and electronic structure calculations using a DFT method.
Perylenequinonoid-catalyzed photoredox activation for the direct arylation of (het)arenes with sunlight
Zhang, Shiwei,Tang, Zhaocheng,Bao, Wenhao,Li, Jia,Guo, Baodang,Huang, Shuping,Zhang, Yan,Rao, Yijian
supporting information, p. 4364 - 4369 (2019/05/10)
Naturally occurring perylenequinonoid pigments (PQPs) have attracted considerable attention owing to their excellent properties of photosensitization. They have been widely investigated as an aspect of photophysics and photobiology. However, their applications in photocatalysis are yet to be explored. We report here that sunlight along with 1 mol% cercosporin, which is one of the perylenequinonoid pigments, catalyzes the direct C-H bond arylation of (het)arenes by a photoredox process with good regioselectivity and broad functional group compatibility. Furthermore, a gram-scale reaction with great conversions of substrates was achieved even by a cercosporin-containing supernatant without organic solvent extraction and purification after liquid fermentation. Thus we set up a bridge between microbial fermentation and organic photocatalysis for chemical reactions in a sustainable, environmentally friendly manner.
Metal-Free Aerobic Oxidative Selective C-C Bond Cleavage in Heteroaryl-Containing Primary and Secondary Alcohols
Xia, Anjie,Qi, Xueyu,Mao, Xin,Wu, Xiaoai,Yang, Xin,Zhang, Rong,Xiang, Zhiyu,Lian, Zhong,Chen, Yingchun,Yang, Shengyong
supporting information, (2019/05/07)
A transition-metal-free aerobic oxidative selective C-C bond-cleavage reaction in primary and secondary heteroaryl alcohols is reported. This reaction was highly efficient and tolerated various heteroaryl alcohols, generating a carboxylic acid derivative and a neutral heteroaromatic compound. Experimental studies combined with density functional theory calculations revealed the mechanism underlying the selective C-C bond cleavage. This strategy also provides an alternative simple approach to carboxylation reaction.
A highly efficient and recyclable NiCl2(dppp)/PEG-400 system for Suzuki-Miyaura reaction of aryl chlorides with arylboronic acids
Liao, Yang,Yang, Weisen,Wei, Ting,Cai, Mingzhong
supporting information, p. 1134 - 1142 (2019/04/10)
NiCl2(dppp) in PEG-400 is shown to be a highly efficient catalyst for Suzuki-Miyaura coupling of aryl chlorides with arylboronic acids. The reaction could be conducted at 100 °C using K3PO4 as base, yielding a variety of biaryls in good to excellent yields. The isolation of the products was readily performed by extraction with petroleum ether and NiCl2(dppp)/PEG-400 system could be easily recycled and reused up to five times without significant loss of activity. Our system not only avoids the use of easily volatile and toxic dioxane or toluene as a solvent but also solves the basic problem of nickel catalyst reuse.
Palladium nanoparticles immobilized on the magnetic few layer graphene support as a highly efficient catalyst for ligand free Suzuki cross coupling and homo coupling reactions
Rafiee, Fatemeh,Khavari, Parvaneh,Payami, Zahra,Ansari, Narges
, p. 78 - 85 (2019/01/30)
In this study, we prepared a magnetic metal–graphene nanocomposite for the synthesis of substituted biaryls via Suzuki cross coupling and homo coupling reaction of aryl halides. The magnetic few layer graphene composite was synthesized by using one-step electrochemical exfoliation of graphite foil in aqueous iron (II) ammonium sulfate as electrolyte without using of any additive or corrosive media. Then, Fe2O3@FLG composite was used an efficient support for the immobilization and suitable dispersing of palladium nanoparticles. The obtained Fe2O3@FLG@Pd0 nanocomposite was characterized using FT-IR, SEM, TEM, EDS, XRD, VSM and ICP-AES analysis. Very low loading of this catalyst was displayed high activity in the producing substituted biaryls. It simply recovered from the reaction mixture and reused without any pre-activation in six consecutive runs with no loss of its catalytic activity or the observation of any detectable palladium leaching process.
N,S-chelating triazole-thioether ligand for highly efficient palladium-catalyzed Suzuki reaction
Yan, Qiong,Zheng, Lei,Li, Miaomiao,Chen, Yunfeng
, p. 101 - 105 (2019/07/19)
1,2,3-Triazole-thioether compounds could serve as efficient ligands for Pd-catalyzed Suzuki reactions of various aryl iodides, bromides and chlorides. The reactions feature wide substrate scope and mild reaction conditions. Besides, shorter reaction time, lower catalyst loadings and quantitative yields with a turnover-frequency (TOF) value of up to 11,880 h?1 are other advantageous of this attractive protocol. The crystal structure analyses and computational studies revealed that the higher catalytic activity of the corresponding chelated palladium complex ascribed to the lower energy gap and the lower redox potential.
