36707-27-4Relevant academic research and scientific papers
Well-defined cyclopropenone-masked dibenzocyclooctyne functionalized polymers from atom transfer radical polymerization
Sun, Peng,Yan, Guowei,Tang, Qingquan,Chen, Yongming,Zhang, Ke
, p. 202 - 209 (2015)
Two functional atom transfer radical polymerization (ATRP) initiators (I-2 and I-3) were developed bearing a cyclopropenone-masked dibenzocyclooctyne group. ATRP was then explored on three main kinds of monomers for radical polymerization including acryla
T-shaped and H-shaped polymers constructed from UV-induced strain promoted azide-alkyne cycloaddition reaction
Zhu, Wen,Li, Zi,Sun, Peng,Ren, Lixia,Zhang, Ke
, p. 1 - 7 (2016)
Topological polymers with T-shaped and H-shaped molecular architecture were built on the combination of atom transfer radical polymerization (ATRP) and UV-induced strain promoted azide-alkyne cycloaddition (SPAAC) reaction. In the presence of a cycloprope
Synthesis of Dibenzyls by Nickel-Catalyzed Homocoupling of Benzyl Alcohols
Pan, Feng-Feng,Guo, Peng,Huang, Xiaochuang,Shu, Xing-Zhong
, p. 3094 - 3100 (2021/04/23)
Dibenzyls are essential building blocks that are widely used in organic synthesis, and they are typically prepared by the homocoupling of halides, organometallics, and ethers. Herein, we report an approach to this class of compounds using alcohols, which are more stable and readily available. The reaction proceeds via nickel-catalyzed and dimethyl oxalate assisted dynamic kinetic homocoupling of benzyl alcohols. Both primary and secondary alcohols are tolerated.
Mixed Alkyl/Aryl Diphos Ligands for Iron-Catalyzed Negishi and Kumada Cross Coupling Towards the Synthesis of Diarylmethane
Ma, Xufeng,Wang, Han,Liu, Yao,Zhao, Xing,Zhang, Jun
, p. 5134 - 5140 (2021/11/16)
Mixed alkyl/aryl diphos ligands have been prepared and their application in iron-catalyzed cross coupling of benzylic chlorides with diaryl zinc (Negishi) or aryl Grignard reagents (Kumada) towards the synthesis of diarylmethane has been evaluated. The iron?diphos catalytic system exhibited the enhanced activity and selectivity in the two coupling reactions. The electron-rich mixed PPh2/PCy2 ligands outperformed their symmetrical PPh2 congeners, and led to decreased homocoupling byproduct formation. It indicates that the electronic effect of the ligands plays an important role in the catalytic performance. The Fe catalyst supported by L8 bearing an electron-rich PCy2 substituent and a sterically demanding tert-butyl on ethene backbone exhibited the best catalytic performance and good functional group tolerance in the two cross coupling reactions.
Reactions of benzyltriphenylphosphonium salts under photoredox catalysis
Boldt, Andrew M.,Dickinson, Sidney I.,Ramirez, Jonathan R.,Benz-Weeden, Anna M.,Wilson, David S.,Stevenson, Susan M.
supporting information, p. 7810 - 7815 (2021/09/28)
The development of benzyltriphenylphosphonium salts as alkyl radical precursors using photoredox catalysis is described. Depending on substituents, the benzylic radicals may couple to form C-C bonds or abstract a hydrogen atom to form C-H bonds. A natural product, brittonin A, was also synthesized using this method.
Ni-Catalyzed Iterative Alkyl Transfer from Nitrogen Enabled by the in Situ Methylation of Tertiary Amines
Nwachukwu, Chideraa Iheanyi,McFadden, Timothy Patrick,Roberts, Andrew George
, p. 9979 - 9992 (2020/09/03)
Current methods to achieve transition-metal-catalyzed alkyl carbon-nitrogen (C-N) bond cleavage require the preformation of ammonium, pyridinium, or sulfonamide derivatives from the corresponding alkyl amines. These activated substrates permit C-N bond cleavage, and their resultant intermediates can be intercepted to affect carbon-carbon bond-forming transforms. Here, we report the combination of in situ amine methylation and Ni-catalyzed benzalkyl C-N bond cleavage under reductive conditions. This method permits iterative alkyl group transfer from tertiary amines and demonstrates a deaminative strategy for the construction of Csp3-Csp3 bonds. We demonstrate PO(OMe)3 (trimethylphosphate) to be a Ni-compatible methylation reagent for the in situ conversion of trialkyl amines into tetraalkylammonium salts. Single, double, and triple benzalkyl group transfers can all be achieved from the appropriately substituted tertiary amines. Transformations developed herein proceed via recurring events: The in situ methylation of tertiary amines by PO(OMe)3, Ni-catalyzed C-N bond cleavage, and concurrent Csp3-Csp3 bond formation.
A Bisphenolic Honokiol Analog Outcompetes Oral Antimicrobial Agent Cetylpyridinium Chloride via a Membrane-Associated Mechanism
Ochoa, Cristian,Solinski, Amy E.,Nowlan, Marcus,Dekarske, Madeline M.,Wuest, William M.,Kozlowski, Marisa C.
, p. 74 - 79 (2019/11/20)
Targeting Streptococcus mutans is the primary focus in reducing dental caries, one of the most common maladies in the world. Previously, our groups discovered a potent bactericidal biaryl compound that was inspired by the natural product honokiol. Herein, a structure activity relationship (SAR) study to ascertain structural motifs key to inhibition is outlined. Furthermore, mechanism studies show that bacterial membrane disruption is central to the bacterial growth inhibition. During this process, it was discovered that analog C2 demonstrated a 4-fold better therapeutic index compared to the commercially available antimicrobial cetylpyridinium chloride (CPC) making it a viable alternative for oral care.
Photo-induced and Rapid Labeling of Tetrazine-Bearing Proteins via Cyclopropenone-Caged Bicyclononynes
Mayer, Susanne V.,Murnauer, Anton,von Wrisberg, Marie-Kristin,Jokisch, Marie-Lena,Lang, Kathrin
, p. 15876 - 15882 (2019/10/28)
Inverse electron-demand Diels–Alder cycloadditions (iEDDAC) between tetrazines and strained alkenes/alkynes have emerged as essential tools for studying and manipulating biomolecules. A light-triggered version of iEDDAC (photo-iEDDAC) is presented that confers spatio-temporal control to bioorthogonal labeling in vitro and in cellulo. A cyclopropenone-caged dibenzoannulated bicyclo[6.1.0]nonyne probe (photo-DMBO) was designed that is unreactive towards tetrazines before light-activation, but engages in iEDDAC after irradiation at 365 nm. Aminoacyl tRNA synthetase/tRNA pairs were discovered for efficient site-specific incorporation of tetrazine-containing amino acids into proteins in living cells. In situ light activation of photo-DMBO conjugates allows labeling of tetrazine-modified proteins in living E. coli. This allows proteins in living cells to be modified in a spatio-temporally controlled manner and may be extended to photo-induced and site-specific protein labeling in animals.
Photoredox-Catalysis-Modulated, Nickel-Catalyzed Divergent Difunctionalization of Ethylene
Li, Jiesheng,Luo, Yixin,Cheo, Han Wen,Lan, Yu,Wu, Jie
supporting information, p. 192 - 203 (2019/01/21)
Divergent synthesis that enables a catalytic reaction to selectively produce different products from common substrates will allow the charting of wider chemical space and the unveiling of distinct mechanistic paradigms. A common strategy for it employs different ligands to modulate organometallic catalysts. Dramatic developments in photocatalysis have enabled previously inaccessible transformations. In particular, photoredox catalysis modulates the oxidation state of transition-metal complexes, offering enormous opportunities for methodology development. Herein, we developed a photo-mediated divergent ethylene difunctionalization via modulating oxidation states of the nickel catalyst by using different photoredox catalysts. This work will inspire new perspectives for value-added chemical synthesis using ethylene as a feedstock and shed light on photoredox-catalyst-based divergent synthesis, which fundamentally differs from ligand-controlled transition-metal catalysis.Divergent synthesis represents a powerful strategy for directly accessing different molecular scaffolds originating from the same starting materials. Access to different end products via transition-metal catalysis is conventionally achieved by ligand control. We herein demonstrate the use of ethylene feedstock and commercially available aryl halides to accomplish the divergent synthesis of 1,2-diarylethanes, 1,4-diarylbutanes, or 2,3-diarylbutanes in a highly selective fashion through the synergistic combination of nickel and photoredox catalysis. Mechanistic studies suggest that the observed selectivity was due to different active states of Ni(I) and Ni(0) modulated by Ru- and Ir-based photoredox catalysts, respectively. The ability to access different organometallic oxidation states via photoredox catalysis promises to inspire new perspectives for synergistic transition-metal-catalyzed divergent synthesis.Functionalization of ethylene without polymerization is challenging under photo-irradiation conditions. We have demonstrated that the photo-transformation of ethylene can be controllable by merging photoredox and transition-metal catalysis. In our study, the use of different photoredox catalysts was able to modulate the oxidation state of the nickel catalyst. Through different oxidation states, the nickel-catalyzed couplings proceeded via distinct pathways to generate divergent ethylene difunctionalization products selectively from the same feedstock.
Mechanistic Insights into Concerted C-C Reductive Elimination from Homoleptic Uranium Alkyls
Johnson, Sara A.,Higgins, Robert F.,Abu-Omar, Mahdi M.,Shores, Matthew P.,Bart, Suzanne C.
supporting information, p. 3491 - 3497 (2017/10/03)
A mechanistic study was carried out to probe concerted C-C reductive elimination from homoleptic uranium(IV) alkyls. The para-chloro uranium(IV) tetrabenzyl derivative, U(CH2-p-ClC6H4)4 (2-p-Cl), was synthesized by treating UCl4 with 4 equivalents of KCH2-p-Cl-Ph (1-p-Cl) at 108 °C, adding a new member to the previously reported family of uranium alkyl complexes U(CH2C6H5)4 (2-Bn), U(CH2-p-iPrC6H4)4 (2-p-iPr), U(CH2-ptBu-C6H4)4 (2-p-tBu), U(CH2-o-OMeC6H4)4 (2-o-OMe), and U(CH2-m-OMeC6H4)4 (2-m-OMe). Each member of this family readily reacts with the redox-active α-diimine ligand, MesDABMe (MesDABMe = [MesN = C(Me)C(Me) = NMes]; Mes = 2,4,6-trimethylphenyl), to afford the products from C-C reductive elimination, namely, (MesDABMe)U(CH2Ph′)2 and Ph′CH2CH2Ph′ (Ph′ = p-iPrC6H4, p-tBuC6H4, m-OMeC6H4, p-ClC6H4). Room-temperature magnetic-susceptibility values, obtained via SQUID magnetometry, show a correlation with an increase in the magnetic moment as the electron-withdrawing character of the substituent increases. Kinetic studies were used to assess the effect of the benzyl substituent on the rate of reductive elimination, showing that reaction rate increases as the electron-withdrawing nature of the substitution increases. Eyring data revealed a large and negative entropy value, indicative of a highly ordered transition state, consistent with the previously reported concerted elimination concluded from crossover experiments.
