90585-32-3Relevant academic research and scientific papers
Synthesis of benzo[b]chalcogenophenes fused to selenophenesviaintramolecular electrophilic cyclization of 1,3-diynes
Hellwig, Paola S.,Guedes, Jonatan S.,Barcellos, Angelita M.,Jacob, Raquel G.,Silveira, Claudio C.,Lenard?o, Eder J.,Perin, Gelson
supporting information, p. 596 - 604 (2021/02/06)
We describe herein an alternative and transition-metal-free procedure for the access of benzo[b]chalcogenophenes fused to selenophenesviaintramolecular cyclization of 1,3-diynes. This efficient protocol involves a double cyclization of 1,3-diynyl chalcogen derivatives promoted by the electrophilic species of organoselenium generatedin situby the oxidative cleavage of the Se-Se bond of dibutyl diselenide using Oxone in acetonitrile as solvent in an open-flask at 80 °C. In this study, 15 selenophenes with broad substrate scope were prepared in moderate to excellent yields (55-98%) with short reaction times (0.5-3.0 h).
Iron-Catalyzed Regioselective Alkenylboration of Olefins
Yu, Xiaolong,Zheng, Hongling,Zhao, Haonan,Lee, Boon Chong,Koh, Ming Joo
supporting information, p. 2104 - 2109 (2020/11/30)
The first examples of an iron-catalyzed three-component synthesis of homoallylic boronates from regioselective union of bis(pinacolato)diboron, an alkenyl halide (bromide, chloride or fluoride), and an olefin are disclosed. Products that bear tertiary or quaternary carbon centers could be generated in up to 87 % yield as single regioisomers with complete retention of the olefin stereochemistry. With cyclopropylidene-containing substrates, ring cleavage leading to trisubstituted E-alkenylboronates were selectively obtained. Mechanistic studies revealed reaction attributes that are distinct from previously reported alkene carboboration pathways.
Nickel-Catalyzed, Regio- and Enantioselective Benzylic Alkenylation of Olefins with Alkenyl Bromide
Liu, Jiandong,Gong, Hegui,Zhu, Shaolin
supporting information, p. 4060 - 4064 (2020/12/25)
A NiH-catalyzed migratory hydroalkenylation reaction of olefins with alkenyl bromides has been developed, affording benzylic alkenylation products with high yields and excellent chemoselectivity. The mild conditions of the reaction preclude olefinic products from undergoing further isomerization or subsequent alkenylation. Catalytic enantioselective hydroalkenylation of styrenes was achieved by using a chiral bisoxazoline ligand.
Design, synthesis and application of triazole ligands in suzuki miyaura cross coupling reaction of aryl chlorides
Jabeen, Sobia,Khera, Rasheed Ahmad,Iqbal, Javed,Asgher, Muhammad
, (2020/01/28)
DFT calculations have been demonstrated to be a valuable tool for the mechanistic study of reaction which is difficult to acquire from pure experimental techniques. Structural, electronic and coordination aspects of synthesized triazole ligands were investigated theoretically by structure optimization on Gaussian 09 package by DFT approach at B3LYP/6-31G (d, p). HOMO-LUMO energy gaps correlated to its chemical reactivity and this information applied to interpret the role of ligand in the formation of ligand-metal complex. Electron rich environment around the triazole core stabilized the HOMO orbital and made these electrons available to form complex with Pd centre. The DFT calculations provide a plausible mechanism for the reaction that is consistent with the available experimental facts. A series of triazole ligands have been synthesized via efficient 1,3-dipolar cycloaddition of readily available azide and alkynes for coordination to Pd centre. Characterization of all the synthesized compounds was done by FTIR, 1H NMR, 13C NMR and HRMS. Their ligand-Pd complexes provided excellent yields in the Suzuki-Miyaura coupling reactions (up to 92% yield) of unactivated aryl chlorides. Ligand 4-(2,6-dimethoxyphenyl)-1-phenyl-1H-1,2,3-triazole (L2) was found to be most effective ligand because of electron donating 2,6 dimethoxy phenyl moiety attached to triazole ring at 4-position that facilitated the formation of electron rich ligand-catalyst complex. The complex favoured the oxidative addition step of Pd across the aryl chloride substrate and thus allowed for the development of highly active ligand-catalyst system for Suzuki reaction. During computational analysis, 4-(2,6-dimethoxyphenyl)-1-phenyl-1H-1,2,3-triazole (L2) also showed lowest band gap due to electron rich distribution pattern on the HOMO that are involve in ligand-Pd complex formation. Conclusively, these triazoles ligands were found to be more competent and attractive for palladium catalyst because of simplistic pathway for the synthesis of triazole motif and the ease of individual tuning of the substituents on triazole core or exocyclic to it.
The hydrodebromination of 1,1-dibromoalkenes via visible light catalysis
Sun, Wencheng,Teng, Qiaoling,Cheng, Dongping,Li, Xiaonian,Xu, Xiaoliang
supporting information, (2019/12/05)
Vinyl bromides are versatile synthetic intermediates and widely applied in organic synthesis and pharmaceuticals. Herein, a hydrodebromination reaction of 1,1-dibromoalkenes was established via visible light catalysis. A variety of structurally different vinyl bromides were obtained in moderate to excellent yields.
Dual nickel- and photoredox-catalyzed reductive cross-coupling of aryl vinyl halides and unactivated tertiary alkyl bromides
Yu, Weijie,Chen, Long,Tao, Jiasi,Wang, Tao,Fu, Junkai
supporting information, p. 5918 - 5921 (2019/05/27)
A novel reductive cross-coupling of aryl vinyl halides and unactivated tertiary alkyl bromides has been realized via photoredox/nickel dual catalysis to produce vinyl arene derivatives bearing all-carbon quaternary centers with excellent E-selectivity. A stoichiometric metal reductant could be avoided by employing commercially available N,N,N′,N′-tetramethylethylenediamine (TMEDA) as the terminal reductant.
Synthesis of Triazole Click Ligands for Suzuki-Miyaura Cross-Coupling of Aryl Chlorides
Jabeen,Khera,Iqbal,Asgher
, p. 1416 - 1422 (2019/11/03)
A series of new triazole ligands has been synthesized via copper-catalyzed cycloaddition reaction of readily available azides and alkynes. The synthesized compounds were characterized by FTIR, 1H and 13C NMR, and high-resolution mass spectra. The ligands provided excellent yields (up to 92%) in the palladium-catalyzed Suzuki-Miyaura cross coupling of unactivated aryl chlorides with phenylboronic acid. 1-Benzyl-4-(2,6-dimethoxyphenyl)-lH-1,2,3-triazole was found to be the most effective ligand due to the presence of electron-donating 2,6-dimethoxyphenyl substituent, which made it possible to develop a highly active ligand-catalyst system for the Suzuki reaction of aryl chlorides.
Construction of Phenanthrenes and Chrysenes from β-Bromovinylarenes via Aryne Diels-Alder Reaction/Aromatization
Singh, Vikram,Verma, Ram Subhawan,Khatana, Anil K.,Tiwari, Bhoopendra
supporting information, p. 14161 - 14167 (2019/10/28)
A highly efficient transition-metal-free general method for the synthesis of polycyclic aromatic hydrocarbons like phenanthrenes and chrysenes (and tetraphene) from β-bromovinylarenes and arynes has been developed. The reactions proceed via an aryne Diels-Alder (ADA) reaction, followed by a facile aromatization. This is the first report on direct construction of chrysenes (and tetraphene) using the ADA approach. Unlike the literature method which is limited to only 9/10-substituted derivatives, this method gives access to a wide variety of functionalized phenanthrenes.
Visible Light-Catalyzed Decarboxylative Alkynylation of Arenediazonium Salts with Alkynyl Carboxylic Acids: Direct Access to Aryl Alkynes by Organic Photoredox Catalysis
Yang, Liangfeng,Li, Haifeng,Du, Yijun,Cheng, Kai,Qi, Chenze
, p. 5030 - 5041 (2019/11/03)
A convenient method mediated by photoredox catalysis is developed for the direct construction of aryl alkynes. Readily available aromatic diazonium salts have been utilized as the aryl radical source to couple alkynyl carboxylic acids to feature the decarboxylative arylation. A wide range of substrates are amenable to this protocol with broad functional group tolerance, and diversely-functionalized aryl alkynes could be synthesized under mild, neutral and transition metal-free reaction conditions using visible light irradiation. Alongside synthetic sustainability associated with the photocatalytic and transition metal-free operation, another key point of this method is that the organic dye catalyst acts as an excited-state reductant, thus establishing the quenching cycle for radical addition and decarboxylative elimination. (Figure presented.).
Rhodium-catalyzed enantioselective decarboxylative alkynylation of allenes with arylpropiolic acids
Grugel, Christian P.,Breit, Bernhard
supporting information, p. 1066 - 1069 (2018/02/23)
A rhodium-catalyzed chemo-, regio-, and enantioselective intermolecular decarboxylative alkynylation of terminal allenes with arylpropiolic acids is reported. Employing a Rh(I)/(R)-Tol-BINAP catalytic system, branched allylic 1,4-enynes were obtained under mild conditions. The overall utility of this protocol is exemplified by a broad functional group compatibility.
