728-86-9Relevant academic research and scientific papers
Synthesis, coordination and catalytic use of phosphinoferrocene ligands bearing 6-phospha-2,4,6-trioxaadamantane P-donor moieties
?těpni?ka, Petr,Císa?ová, Ivana,Horky, Filip
, (2021/11/11)
1,1’-Bis(diphenylphosphino)ferrocene (dppf) and structurally related ferrocene bis-phosphines are indispensable ligands for coordination chemistry and catalysis. This contribution focuses on the coordination behaviour and catalytic properties of two dppf congeners bearing 1,3,5,7-tetramethyl-2,4,6-trioxa-8-phosphatricyclo[3.3.1.13,7]decane-8-yl groups (CgP) as the P-donor moieties, viz. Ph2PfcCgP (1) and its semi-homologous counterpart Ph2PfcCH2CgP (2; fc = ferrocene-1,1’-diyl). In reactions with a PdCl2 source, compound 1 produced exclusively the cis-chelate complex [PdCl2(1-κ2P,P’)], while the homologated ligand 2 afforded a complex mixture of compounds which equilibrated upon heating in methanol in favour of the symmetrical dimeric complex trans-[(μ-2)PdCl2]2 as a mixture of racemic and meso isomers. Notably, in aqueous Pd-catalysed cyanation of aryl bromides and Suzuki-Miyaura-type cross-coupling of benzoyl chlorides with boronic acids producing benzophenones, catalysts generated in situ from bis-phosphine 1 and Pd(II) sources were often more active than their counterparts resulting from dppf and 2.
C(acyl)-C(sp2) and C(sp2)-C(sp2) Suzuki-Miyaura cross-coupling reactions using nitrile-functionalized NHC palladium complexes
?akir, Sinem,Karabiyik, Hande,Kavukcu, Serdar Batikan,Rethinam, Senthil,Türkmen, Hayati
, p. 37684 - 37699 (2021/12/09)
Application of N-heterocyclic carbene (NHC) palladium complexes has been successful for the modulation of C-C coupling reactions. For this purpose, a series of azolium salts (1a-f) including benzothiazolium, benzimidazolium, and imidazolium, bearing a CN-substituted benzyl moiety, and their (NHC)2PdBr2 (2a-c) and PEPPSI-type palladium (3b-f) complexes have been systematically prepared to catalyse acylative Suzuki-Miyaura coupling reaction of acyl chlorides with arylboronic acids to form benzophenone derivatives in the presence of potassium carbonate as a base and to catalyse the traditional Suzuki-Miyaura coupling reaction of bromobenzene with arylboronic acids to form biaryls. All the synthesized compounds were fully characterized by Fourier Transform Infrared (FTIR), and 1H and 13C NMR spectroscopies. X-ray diffraction studies on single crystals of 3c, 3e and 3f prove the square planar geometry. Scanning Electron Microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), metal mapping analyses and thermal gravimetric analysis (TGA) were performed to get further insights into the mechanism of the Suzuki-Miyaura cross coupling reactions. Mechanistic studies have revealed that the stability and coordination of the complexes by the CN group are achieved by the removal of pyridine from the complex in catalytic cycles. The presence of the CN group in the (NHC)Pd complexes significantly increased the catalytic activities for both reactions.
Aromatization as an Impetus to Harness Ketones for Metallaphotoredox-Catalyzed Benzoylation/Benzylation of (Hetero)arenes
Chen, Ting-Wei,Cheng, Cheng-Ku,Chiu, Cheng-Chau,Huang, Pin-Gong,Lee, Shao-Chi,Lee, Yi-Hsin,Li, Li-Yun,Liao, Hsuan-Hung,Lin, Heng-Bo,Tsai, Zong-Nan,Tsao, Yong-Ting,Yang, Chung-Hsin
, (2022/01/04)
Herein we report ketones as feedstock materials in radical cross-coupling reactions under Ni/photoredox dual catalysis. In this approach, simple condensation first converts ketones into prearomatic intermediates that then act as activated radical sources for cross-coupling with aryl halides. Our strategy enables the direct benzylation/benzoylation of (hetero)arenes under mild reaction conditions with high functional group tolerance.
Palladium-Catalyzed Aminocarbonylation of Aryl Halides with N,N-Dialkylformamide Acetals
Hirata, Shuichi,Osako, Takao,Uozumi, Yasuhiro
, (2021/10/05)
We developed a protocol for the palladium-catalyzed aminocarbonylation of aryl halides using less-toxic formamide acetals as bench-stable aminocarbonyl sources under neutral conditions. Various aryl (including heteroaryl) halides reacted with N,N-dialkylformamide acetals in the presence of a catalytic amount of tris(dibenzylideneacetone)dipalladium(0)-chloroform adduct and xantphos to give the corresponding aromatic carboxamides at 90–140 °C without any activating agents or bases in up to quantitative chemical yield. This protocol was applied to aryl bromides, aryl iodides, and trifluoromethanesulfonic acid, as well as to relatively less-reactive aryl chlorides. A wide range of functionalities on the aromatic ring of the substrates were tolerated under the aminocarbonylation conditions. The catalytic aminocarbonylation was used to prepare the insect repellent N,N-diethyl-3-methylbenzamide as well as a synthetic intermediate of the dihydrofolate reductase inhibitor triazinate.
Evaluation of Cyclic Amides as Activating Groups in N-C Bond Cross-Coupling: Discovery of N-Acyl-δ-valerolactams as Effective Twisted Amide Precursors for Cross-Coupling Reactions
Bisz, Elwira,Chen, Hao,Dziuk, B?a?ej,Ejsmont, Krzysztof,Lalancette, Roger,Pyle, Daniel J.,Rahman, Md. Mahbubur,Szostak, Michal,Szostak, Roman,Wang, Qi
, p. 10455 - 10466 (2021/07/31)
The development of efficient methods for facilitating N-C(O) bond activation in amides is an important objective in organic synthesis that permits the manipulation of the traditionally unreactive amide bonds. Herein, we report a comparative evaluation of a series of cyclic amides as activating groups in amide N-C(O) bond cross-coupling. Evaluation of N-acyl-imides, N-acyl-lactams, and N-acyl-oxazolidinones bearing five- and six-membered rings using Pd(II)-NHC and Pd-phosphine systems reveals the relative reactivity order of N-activating groups in Suzuki-Miyaura cross-coupling. The reactivity of activated phenolic esters and thioesters is evaluated for comparison in O-C(O) and S-C(O) cross-coupling under the same reaction conditions. Most notably, the study reveals N-acyl-δ-valerolactams as a highly effective class of mono-N-acyl-activated amide precursors in cross-coupling. The X-ray structure of the model N-acyl-δ-valerolactam is characterized by an additive Winkler-Dunitz distortion parameter ?(τ+χN) of 54.0°, placing this amide in a medium distortion range of twisted amides. Computational studies provide insight into the structural and energetic parameters of the amide bond, including amidic resonance, N/O-protonation aptitude, and the rotational barrier around the N-C(O) axis. This class of N-acyl-lactams will be a valuable addition to the growing portfolio of amide electrophiles for cross-coupling reactions by acyl-metal intermediates.
Acylboronates in polarity-reversed generation of acyl palladium(II) intermediates
Trofimova, Alina,Holownia, Aleksandra,Tien, Chieh-Hung,?irvinskas, Martynas J.,Yudin, Andrei K.
supporting information, p. 3294 - 3299 (2021/05/07)
We report a catalytic cross-coupling process between aryl (pseudo)halides and boron-based acyl anion equivalents. This mode of acylboronate reactivity represents polarity reversal, which is supported by the observation of tetracoordinated boronate and acyl palladium(II) species by 11B, 31P NMR, and mass spectrometry. A broad scope of aliphatic and aromatic acylboronates has been examined, as well as a variety of aryl (pseudo)halides.
Pd-Catalysed carbonylative Suzuki-Miyaura cross-couplings using Fe(CO)5under mild conditions: generation of a highly active, recyclable and scalable ‘Pd-Fe’ nanocatalyst
Zhu, Zhuangli,Wang, Zhenhua,Jian, Yajun,Sun, Huaming,Zhang, Guofang,Lynam, Jason M.,McElroy, C. Robert,Burden, Thomas J.,Inight, Rebecca L.,Fairlamb, Ian J. S.,Zhang, Weiqiang,Gao, Ziwei
supporting information, p. 920 - 926 (2021/02/09)
The dual function and role of iron(0) pentacarbonyl [Fe(CO)5] has been identified in gaseous CO-free carbonylative Suzuki-Miyaura cross-couplings, in which Fe(CO)5supplied COin situ, leading to the propagation of catalytically active Pd-Fe nanoparticles. Compared with typical carbonylative reaction conditions, CO gas (at high pressures), specialised exogenous ligands and inert reaction conditions were avoided. Our developed reaction conditions are mild, do not require specialised CO high pressure equipment, and exhibit wide functional group tolerance, giving a library of biaryl ketones in good yields.
AIBN initiated functionalization of the benzylic sp3 C[sbnd]H and C[sbnd]C bonds in the presence of dioxygen
Hu, Yingying,Shao, Yu,Zhang, Shuwei,Yuan, Yuan,Sun, Zheng,Yuan, Yu,Jia, Xiaodong
supporting information, (2021/02/01)
A sp3 C[sbnd]H bond functionalization and C[sbnd]C bond cleavage were realized by AIBN/O2 catalyst system, providing a series of benzophenones under mild reaction conditions. The mechanistic study shows that a peroxide intermediate is involved in this transformation, and in the case of diphenylmethanes, the sp3 C[sbnd]C bond is cleaved through the peroxide rearrangement, which might provides a new way to cleave relatively strong C[sbnd]C bond and be applied to more general C[sbnd]C bond activation.
Synthesis of biaryl ketones and biaryl diketones via carbonylative Suzuki-Miyaura coupling reactions catalyzed by bridged bis(N-heterocyclic carbene)palladium(II) catalysts
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Page/Page column 20; 25-26; 29-30, (2021/12/23)
This disclosure relates to bridged bis(N-heterocyclic carbene)palladium(II) complexes, methods of preparing the complexes, and methods of using the complexes in Suzuki-Miyaura coupling reactions.
Complexes: Easily Synthesized, Highly Active Pd(II)-NHC Precatalysts for Cross-Coupling Reactions
Xia, Qinqin,Shi, Shicheng,Gao, Pengcheng,Lalancette, Roger,Szostak, Roman,Szostak, Michal
, p. 15648 - 15657 (2021/10/25)
We report the synthesis, characterization, and reactivity of [(NHC)PdCl2(aniline)] complexes. These well-defined, air- and moisture-stable catalysts are highly active in the Suzuki-Miyaura cross-coupling of amides by N-C(O) activation as well as in the Suzuki-Miyaura cross-coupling of esters, aryl chlorides, and Buchwald-Hartwig amination. Most crucially, this study introduces broadly available anilines as stabilizing ligands for well-defined Pd(II)-NHC catalysts. The availability of various aniline scaffolds, including structural and electronic diversity, has a significant potential in fine-tuning of challenging cross-couplings by Pd-NHCs. The parent catalyst in this class, [Pd(IPr)(AN)Cl2], has been commercialized in collaboration with Millipore Sigma, offering broad access for reaction screening and optimization.
