1826-11-5Relevant articles and documents
Ferrocenyl (P,N)-diphosphines incorporating pyrrolyl, imidazolyl or benzazaphospholyl moieties: Synthesis, coordination to group 10 metals and performances in palladium-catalyzed arylation reactions
Allouch, Fatima,Vologdin, Nikolay V.,Cattey, Hélène,Pirio, Nadine,Naoufal, Daoud,Kanj, Ali,Smaliy, Radomyr V.,Savateev, Aleksandr,Marchenko, Anatoly,Hurieva, Anastasia,Koidan, Heorgii,Kostyuk, Aleksandr N.,Hierso, Jean-Cyrille
, p. 38 - 46 (2013)
Three novel symmetrical ferrocenyl diphosphines with tertiary phosphorus atoms holding respectively nitrogen-containing heterocyclic derivatives of pyrrole, imidazole and benzazaphosphole were synthesized and characterized. Up to now, integration of heteroaromatic fragments, or more generally hetero-cycles, as substituents on the tertiary phosphines of symmetrical ferrocenyl diphosphines has been limited to the furyl motif. Their coordination to palladium and platinum group 10 transition metals was exemplified, and analyzed using single crystal X-ray diffraction. The performances obtained in palladium-catalyzed copper-free Sonogashira and Suzuki cross-coupling reactions using bromoarenes and chloroarenes are reported for the most efficient system. The unprecedented combination of a tert-butyl group and of an imidazolyl motif on the phosphorus atoms led to an air-stable ferrocenyl diphosphine, which allowed in combination with 0.1-0.2 mol% of palladium to generate catalytic systems able to couple some activated chloroarenes and most of the bromoarenes examined.
Photoswitching of an intramolecular chiral stack in a helical tetrathiazole
Hashimoto, Yuichiro,Nakashima, Takuya,Shimizu, Daiya,Kawai, Tsuyoshi
, p. 5171 - 5174 (2016)
On-off photoswitching of circularly polarized luminescence was achieved using a pyrene-bearing helical tetrathiazole, in which two pyrene fluorophores stack in a chiral fashion (folded state). The pyrene-excimer based CPL was reversibly controlled by a ge
Boosting free radical type photocatalysis over Pd/Fe-MOFs by coordination structure engineering
Bian, Fengxia,Cheng, Hongmei,Dong, Fan,Jiang, Heyan,Jiang, Yanke,Yang, Lin,Zang, Cuicui
, p. 5543 - 5552 (2021/08/25)
The development of novel heterogeneous photocatalytic systems, along with a deep understanding of the relationship between the catalytic center chemical environment and the catalytic performance, is of great significance. Herein, the surface microenvironment of Pd nanoparticles was modulated with engineered Fe-MOF coordination structures (octahedron MIL-100(Fe), concave octahedron MIL-101(Fe) and irregular lumpy MIL-53(Fe)). Two heterogeneous free radical photocatalytic organic transformations have been developed over Pd nanoparticle loaded Fe-MOFs (Pd/Fe-MOFs). The photocatalytic C-H arylation of thiazole and decarboxylation cross-coupling with cinnamic acid were investigated. Thiazole C-H arylation with halobenzenes was brought about through C-halogen bond activation with the photogenerated electron-rich Pd NPs, the aryl radical generation and the follow-up radical addition. The cinnamic acid decarboxylation cross-coupling was also achieved by means of C-halogen bond activation with photogenerated electron-rich Pd NPs. The base regulated the product stereoselectivity by affecting the balance between cinnamic acid and carboxylate anions, as well as the balance between aryl radicals and the coordination complex intermediates. The improvement of the heterogeneous photocatalytic performance for thiazole C-H arylation and cinnamic acid decarboxylation cross-coupling should be ascribed to the difference in the electron transfer efficiency to Pd NPs over various engineered Fe-O cluster coordination structures. This work highlights the importance of exploiting structure engineering for heterogeneous photocatalytic systems.
Switching between mono and doubly reduced odd alternant hydrocarbon: designing a redox catalyst
Ahmed, Jasimuddin,Datta, Paramita,Das, Arpan,Jomy, Stephy,Mandal, Swadhin K.
, p. 3039 - 3049 (2021/03/14)
Since the early Hückel molecular orbital (HMO) calculations in 1950, it has been well known that the odd alternant hydrocarbon (OAH), the phenalenyl (PLY) system, can exist in three redox states: closed shell cation (12π e?), mono-reduced open shell neutral radical (13π e?) and doubly reduced closed shell anion (14π e?). Switching from one redox state of PLY to another leads to a slight structural change owing to its low energy of disproportionation making the electron addition or removal process facile. To date, mono-reduced PLY based radicals have been extensively studied. However, the reactivity and application of doubly reduced PLY species have not been explored so far. In this work, we report the synthesis of the doubly reduced PLY species (14π e?) and its application towards the development of redox catalysisviaswitching with the mono-reduced form (13π e?) for aryl halide activation and functionalization under transition metal free conditions without any external stimuli such as heat, light or cathodic current supply.
Bimetallic Cooperative Catalysis for Decarbonylative Heteroarylation of Carboxylic Acids via C-O/C-H Coupling
Liu, Chengwei,Ji, Chong-Lei,Zhou, Tongliang,Hong, Xin,Szostak, Michal
supporting information, p. 10690 - 10699 (2021/04/09)
Cooperative bimetallic catalysis is a fundamental approach in modern synthetic chemistry. We report bimetallic cooperative catalysis for the direct decarbonylative heteroarylation of ubiquitous carboxylic acids via acyl C-O/C-H coupling. This novel catalytic system exploits the cooperative action of a copper catalyst and a palladium catalyst in decarbonylation, which enables highly chemoselective synthesis of important heterobiaryl motifs through the coupling of carboxylic acids with heteroarenes in the absence of prefunctionalization or directing groups. This cooperative decarbonylative method uses common carboxylic acids and shows a remarkably broad substrate scope (>70 examples), including late-stage modification of pharmaceuticals and streamlined synthesis of bioactive agents. Extensive mechanistic and computational studies were conducted to gain insight into the mechanism of the reaction. The key step involves intersection of the two catalytic cycles via transmetallation of the copper–aryl species with the palladium(II) intermediate generated by oxidative addition/decarbonylation.
Development of Red-Shifted and Fluorogenic Nucleoside and Oligonucleotide Diarylethene Photoswitches
Kolmar, Theresa,Becker, Antonia,Pfretzschner, Ronja A.,Lelke, Alina,J?schke, Andres
supporting information, p. 17386 - 17394 (2021/10/20)
The reversible modulation of fluorescence signals by light is of high interest for applications in super-resolution microscopy, especially on the DNA level. In this article we describe the systematic variation of the core structure in nucleoside-based diarylethenes (DAEs), in order to generate intrinsically fluorescent photochromes. The introduction of aromatic bridging units resulted in a bathochromic shift of the visible absorption maximum of the closed-ring form, but caused reduced thermal stability and switching efficiency. The replacement of the thiophene aryl unit by thiazol improved the thermal stability, whereas the introduction of a benzothiophene unit led to inherent and modulatable turn-off fluorescence. This feature was further optimized by introducing a fluorescent indole nucleobase into the DAE core, resulting in an effective photoswitch with a fluorescence quantum yield of 0.0166 and a fluorescence turn-off factor of 3.2. The site-specific incorporation into an oligonucleotide resulted in fluorescence-switchable DNA with high cyclization quantum yields and switching efficiency, which may facilitate future applications.
Liebeskind-Srogl-type cross-coupling reaction of azole-2-thiones with triarylbismuthines: Synthesis of 2-arylazoles
Murata, Yuki,Terazoe, Aki,Kiba, Misato,Kitamura, Yuki,Matsumura, Mio,Yasuike, Shuji
supporting information, (2020/07/03)
Liebeskind-Srogl-type C(HetAr)–C(Ar) bond formation using trivalent organobismuth compounds as a new class of arylating reagents is described. The reaction of benzazole-2-thiones with triarylbismuthines in the presence of 10 mol% Pd(dba)2 and 2.0 equiv. Cu(OAc)2 at 80 °C affords 2-arylbenzothiazoles, benzoxazoles, and N-methyl benzimidazole in moderate-to-high yield. The reaction is sensitive to the electronic nature of triarylbismuthines: compounds bearing an electron-withdrawing group on the phenyl ring showed higher reactivity than those having an electron-donating group.
Palladium (II)–Salan Complexes as Catalysts for Suzuki–Miyaura C–C Cross-Coupling in Water and Air. Effect of the Various Bridging Units within the Diamine Moieties on the Catalytic Performance
Bunda, Szilvia,Joó, Ferenc,Kathó, ágnes,Udvardy, Antal,Voronova, Krisztina
supporting information, (2020/09/18)
Water-soluble salan ligands were synthesized by hydrogenation and subsequent sulfonation of salens (N,N’-bis(slicylidene)ethylenediamine and analogues) with various bridging units (linkers) connecting the nitrogen atoms. Pd (II) complexes were obtained in reactions of sulfosalans and [PdCl4]2?. Characterization of the ligands and complexes included extensive X-ray diffraction studies, too. The Pd (II) complexes proved highly active catalysts of the Suzuki–Miyaura reaction of aryl halides and arylboronic acid derivatives at 80 ?C in water and air. A comparative study of the Pd (II)–sulfosalan catalysts showed that the catalytic activity largely increased with increasing linker length and with increasing steric congestion around the N donor atoms of the ligands; the highest specific activity was 40,000 (mol substrate) (mol catalyst × h)?1. The substrate scope was explored with the use of the two most active catalysts, containing 1,4-butylene and 1,2-diphenylethylene linkers, respectively.
miRNA biosynthesis inhibitor
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Paragraph 0061; 0072; 0073; 0174; 0175, (2019/06/12)
The invention provides a compound shown as a formula I, or a conformational isomer thereof, or an optical isomer thereof, or a pharmaceutically acceptable salt thereof. The compound can be tightly combined with related binding proteins in an miRNA biosynthesis process and can effectively inhibit the synthesis of miRNA-21. The prepared active compound provided by the invention can be used as an miRNA-21 inhibitor, and further as a potential drug for treating malignant tumors. The formula I is shown in the description.
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
, (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.
