2216-92-4Relevant academic research and scientific papers
Synthesis, isolation and characterization of cationic gold(I) N-heterocyclic carbene (NHC) complexes
De Fremont, Pierre,Stevens, Edwin D.,Fructos, Manuel R.,Mar Diaz-Requejo,Perez, Pedro J.,Nolan, Steven P.
, p. 2045 - 2047 (2006)
A number of cationic gold(I) complexes have been synthesized and found to be stabilized by the use of N-heterocyclic carbene ligands. These species are often employed as in situ-generated reactive intermediates in gold catalyzed organic transformations. An isolated, well-defined species was tested in gold-mediated carbene transfer reactions from ethyl diazoacetate. The Royal Society of Chemistry 2006.
Noncanonical Heme Ligands Steer Carbene Transfer Reactivity in an Artificial Metalloenzyme**
Dunkelmann, Daniel,Hayashi, Takahiro,Hilvert, Donald,Mittl, Peer R. E.,Ota, Yusuke,Pott, Moritz,Tinzl, Matthias
, p. 15063 - 15068 (2021)
Changing the primary metal coordination sphere is a powerful strategy for tuning metalloprotein properties. Here we used amber stop codon suppression with engineered pyrrolysyl-tRNA synthetases, including two newly evolved enzymes, to replace the proximal histidine in myoglobin with Nδ-methylhistidine, 5-thiazoylalanine, 4-thiazoylalanine and 3-(3-thienyl)alanine. In addition to tuning the heme redox potential over a >200 mV range, these noncanonical ligands modulate the protein's carbene transfer activity with ethyl diazoacetate. Variants with increased reduction potential proved superior for cyclopropanation and N–H insertion, whereas variants with reduced Eo values gave higher S–H insertion activity. Given the functional importance of histidine in many enzymes, these genetically encoded analogues could be valuable tools for probing mechanism and enabling new chemistries.
Silver-prompted carbonitration of acrylamides for the synthesis of nitrating oxindoles
Wei, Xiao-Hong,Wu, Quan-Xiang,Yang, Shang-Dong
, p. 1417 - 1421 (2015)
A silver-prompted carbonitration of alkenes involving concomitant direct C-H functionalization and C-N bond formation to synthesize nitrating oxindoles has been developed. The CR TH2 receptor antagonist skeleton can be obtained from one of the products with further modification.
Catalyst design based on agostic interactions: Synthesis, characterization, and catalytic activity of bis(pyrazolyl)borate copper complexes
Cao, Hou-Ji,Zhao, Qianyi,Zhang, Qian-Fan,Li, Jiaxuan,Hamilton, Ewan J. M.,Zhang, Jie,Wang, Lai-Sheng,Chen, Xuenian
, p. 10194 - 10199 (2016)
Agostic interactions are often used to activate inert C-H bonds, and thus facilitate new reactions. We report the first example of designed catalysts based on the agostic interaction. Novel copper(i) complexes [BBN(pzx)2]Cu(PPh3)n (BBN = 9-borabicyclo[3.3.1]nonane; pzx = 3-substituted pyrazole; x = H, n = 2; x = Me, n = 1) and {[BBN(pziPr)2]Cu}2 have been synthesized and characterized. Single crystal studies of the three compounds show weak intramolecular C-H?Cu interactions which can be assigned as agostic or anagostic interactions. Catalytic studies of these complexes toward carbenoid insertion into N-H bonds indicate these weak interactions act as a "switch" which will be turned "on" if interacting with the substrate and "off" if eliminating the product and regenerating the weak interaction. The process of the "switch" turning "on" or "off", which is related to the catalytic effect, is found to be influenced by both steric effects and the solvent: a less sterically hindered catalyst in non-coordinating benzene results in high yield, while a more sterically hindered catalyst in coordinating THF results in relatively low yield.
Metal Substitution Modulates the Reactivity and Extends the Reaction Scope of Myoglobin Carbene Transfer Catalysts
Sreenilayam, Gopeekrishnan,Moore, Eric J.,Steck, Viktoria,Fasan, Rudi
, p. 2076 - 2089 (2017)
Engineered myoglobins have recently emerged as promising scaffolds for catalyzing carbene-mediated transformations. In this work, we investigated the effect of altering the metal center and first-sphere coordination residue on the carbene transfer reactivity of myoglobin. To this end, we first established an efficient protocol for the recombinant expression of myoglobin variants incorporating metalloporphyrins with non-native metals, including second- and third-row transition metals (ruthenium, rhodium, iridium). Characterization of the cofactor-substituted myoglobin variants across three different carbene transfer reactions (cyclopropanation, N–H insertion, S–H insertion) revealed a major influence of the nature of the metal center, its oxidation state and first-sphere coordination environment on the catalytic activity, stereoselectivity, and/or oxygen tolerance of these artificial metalloenzymes. In addition, myoglobin variants incorporating manganese- or cobalt-porphyrins were found capable of catalyzing an intermolecular carbene C–H insertion reaction involving phthalan and ethyl α-diazoacetate, a reaction not supported by iron-based myoglobins and previously accessed only using iridium-based (bio)catalysts. These studies demonstrate how modification of the metalloporphyrin cofactor environment provides a viable and promising strategy to enhance the catalytic properties and extend the reaction scope of myoglobin-based carbene transfer catalysts. (Figure presented.).
Selective carbene transfer to amines and olefins catalyzed by ruthenium phthalocyanine complexes with donor substituents
Cailler, Lucie P.,Kroitor, Andrey P.,Martynov, Alexander G.,Gorbunova, Yulia G.,Sorokin, Alexander B.
supporting information, p. 2023 - 2031 (2021/02/26)
Electron-rich ruthenium phthalocyanine complexes were evaluated in carbene transfer reactions from ethyl diazoacetate (EDA) to aromatic and aliphatic olefins as well as to a wide range of aromatic, heterocyclic and aliphatic amines for the first time. It was revealed that the ruthenium octabutoxyphthalocyanine carbonyl complex [(BuO)8Pc]Ru(CO) is the most efficient catalyst converting electron-rich and electron-poor aromatic olefins to cyclopropane derivatives with high yields (typically 80-100%) and high TON (up to 1000) under low catalyst loading and nearly equimolar substrate/EDA ratio. This catalyst shows a rare efficiency in the carbene insertion into amine N-H bonds. Using a 0.05 mol% catalyst loading, a high amine concentration (1 M) and 1.1 eq. of EDA, a number of structurally divergent amines were selectively converted to mono-substituted glycine derivatives with up to quantitative yields and turnover numbers reaching 2000. High selectivity, large substrate scope, low catalyst loading and practical reaction conditions place [(BuO)8Pc]Ru(CO) among the most efficient catalysts for the carbene insertion into amines.
Photoredox-Catalyzed α-Aminomethyl Carboxylation of Styrenes with Sodium Glycinates: Synthesis of γ-Amino Acids and γ-Lactams
Zhou, Cong,Li, Miao,Sun, Jianwei,Cheng, Jiang,Sun, Song
supporting information, p. 2895 - 2899 (2021/05/05)
A visible-light photoredox-catalyzed reductive α-aminomethyl carboxylation of styrenes with sodium glycinates and CO2 has been developed to synthesize a series of α,α-disubstituted γ-amino acids and γ-lactams with high efficiency and regioselectivity. Notably, CO2 released from the decarboxylation step can be reused for the subsequent carboxylation. Distinct from the previous reactions with the same type of substrates leading to simple decarboxylation and olefin hydroalkylation, this process involves additional CO2 sequestration, thus leading to olefin α-aminomethyl carboxylation. These findings not only provide new access to α,α-disubstituted γ-amino acids and γ-lactams but also serve as a proof of concept for CO2 reutilization in decarboxylation reactions.
Discovery and evolution of 12N-substituted aloperine derivatives as anti-SARS-CoV-2 agents through targeting late entry stage
Wang, Kun,Wu, Jia-Jing,Xin–Zhang,Zeng, Qing-Xuan,Zhang, Na,Huang, Wei-Jin,Tang, Sheng,Wang, Yan-Xiang,Kong, Wei-Jia,Wang, You-Chun,Li, Ying-Hong,Song, Dan-Qing
, (2021/08/03)
So far, there is still no specific drug against COVID-19. Taking compound 1 with anti-EBOV activity as the lead, fifty-four 12N-substituted aloperine derivatives were synthesized and evaluated for the anti-SARS-CoV-2 activities using pseudotyped virus model. Among them, 8a exhibited the most potential effects against both pseudotyped and authentic SARS-CoV-2, as well as SARS-CoV and MERS-CoV, indicating a broad-spectrum anti-coronavirus profile. The mechanism study disclosed that 8a might block a late stage of viral entry, mainly via inhibiting host cathepsin B activity rather than directly targeting cathepsin B protein. Also, 8a could significantly reduce the release of multiple inflammatory cytokines in a time- and dose-dependent manner, such as IL-6, IL-1β, IL-8 and MCP-1, the major contributors to cytokine storm. Therefore, 8a is a promising agent with the advantages of broad-spectrum anti-coronavirus and anti-cytokine effects, thus worthy of further investigation.
Direct, Site-Selective and Redox-Neutral α-C?H Bond Functionalization of Tetrahydrofurans via Quantum Dots Photocatalysis
Chen, Bin,Ci, Rui-Nan,Huang, Cheng,Liu, Zan,Qiao, Jia,Song, Zi-Qi,Tung, Chen-Ho,Wu, Li-Zhu
supporting information, p. 27201 - 27205 (2021/11/16)
As one of the most ubiquitous bulk reagents available, the intrinsic chemical inertness of tetrahydrofuran (THF) makes direct and site-selective C(sp3)?H bond activation difficult, especially under redox neutral condition. Here, we demonstrate that semiconductor quantum dots (QDs) can activate α-C?H bond of THF via forming QDs/THF conjugates. Under visible light irradiation, the resultant alkoxyalkyl radical directly engages in radical cross-coupling with α-amino radical from amino C?H bonds or radical addition with alkene or phenylacetylene, respectively. In contrast to stoichiometric oxidant or hydrogen atom transfer reagents required in previous studies, the scalable benchtop approach can execute α-C?H bond activation of THF only by a QD photocatalyst under redox-neutral condition, thus providing a broad of value added chemicals starting from bulk THFs reagent.
Perovskite as Recyclable Photocatalyst for Annulation Reaction of N-Sulfonyl Ketimines
Chen, Xiaolan,Qu, Lingbo,Shi, Anzai,Sun, Kai,Yu, Bing,Zhao, Yufen
supporting information, (2022/01/04)
A sustainable and cost-effective manner for the photocatalytic annulation reaction of N-sulfonyl ketimines with N-arylglycines to synthesize imidazolidine-fused sulfamidates (31 examples) by employing CsPbBr3 as a heterogeneous photocatalyst has been developed. The catalyst CsPbBr3 can be simply recovered from the reaction mixture and reused at least five times without an obvious reduction in its photocatalytic reactivity, exhibiting a high catalyst economic feature.
