scholarly journals Synthesis of fused heterocyclic systems via the Mallory photoreaction of arylthienylethenes

2019 ◽  
Vol 18 (12) ◽  
pp. 2901-2911 ◽  
Author(s):  
Natalia V. Dyachenko ◽  
Andrey V. Khoroshutin ◽  
Yulia A. Sotnikova ◽  
Valentina A. Karnoukhova ◽  
Sergey D. Tokarev ◽  
...  
Keyword(s):  
Functional Group ◽  
Conjugated Systems ◽  
Electrocyclic Reaction

A facile and functional group tolerant electrocyclic reaction of styrylthiophenes which allows the synthesis of a series of new tricyclic π-conjugated systems with 39%–74% overall yields is reported.

scholarly journals Addition of alkynes and osmium carbynes towards functionalized dπ–pπ conjugated systems

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Shiyan Chen ◽  
Longzhu Liu ◽  
Xiang Gao ◽  
Yuhui Hua ◽  
Lixia Peng ◽  
...  
Keyword(s):  
Organic Solar Cells ◽  
Room Temperature ◽  
Functional Group ◽  
Isotope Labeling ◽  
Theoretical Calculations ◽  
Functional Materials ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Conjugated Systems ◽  
Triple Bonds

Abstract The metal-carbon triple bonds and carbon-carbon triple bonds are both highly unsaturated bonds. As a result, their reactions tend to afford cycloaddition intermediates or products. Herein, we report a reaction of M≡C and C≡C bonds that affords acyclic addition products. These newly discovered reactions are highly efficient, regio- and stereospecific, with good functional group tolerance, and are robust under air at room temperature. The isotope labeling NMR experiments and theoretical calculations reveal the reaction mechanism. Employing these reactions, functionalized dπ-pπ conjugated systems can be easily constructed and modified. The resulting dπ-pπ conjugated systems were found to be good electron transport layer materials in organic solar cells, with power conversion efficiency up to 16.28% based on the PM6: Y6 non-fullerene system. This work provides a facile, efficient methodology for the preparation of dπ-pπ conjugated systems for use in functional materials.

Equilibrium reactions of n-butanethiol with some conjugated heteroenoid compounds

1968 ◽  
Vol 46 (5) ◽  
pp. 775-781 ◽  
Author(s):  
R. B. Pritchard ◽  
C. E. Lough ◽  
D. J. Currie ◽  
H. L. Holmes
Keyword(s):  
Functional Group ◽  
Equilibrium Constants ◽  
Phenyl Group ◽  
Reverse Reaction ◽  
Experimental Conditions ◽  
Standard Methods ◽  
Conjugated Systems ◽  
Equilibrium Reactions ◽  
Measurable Rate

The reactions of 2-benzal-1,3-indanediones and the cyano-containing benzalmalononitriles, ethyl benzalcyanoacetates, benzalcyanoacetamides, and benzalcyanoacetanilides with n-butanethiol at 25 °C in 20% ethanol – 80% pH 7 buffer attain equlibrium at a rate too fast to measure by standard methods. The equilibrium constants have been calculated and these in turn related to Hammett σ and Taft σ* constants. The differences in the reactions of these and other gem difunctional systems which react virtually completely with n-butanethiol under the same experimental conditions and at a measurable rate, are attributed to participation of the functional group cis to the phenyl group in the reverse reaction. It is shown that n-butanethiol adds to cinnamalacetophenone by a 1,4-mechanism and the reactions of this nucleophile with similar compounds having extended conjugated systems are discussed.

Metal-Free Photoinduced Hydroalkylation Cascade Enabled by an Electron-Donor-Acceptor Complex

2020 ◽  
Author(s):  
José Tiago Menezes Correia ◽  
Gustavo Piva da Silva ◽  
Camila Menezes Kisukuri ◽  
Elias André ◽  
Bruno Pires ◽  
...  
Keyword(s):  
Electron Donor ◽  
Functional Group ◽  
Photoexcited Electron ◽  
One Pot ◽  
Quaternary Centers ◽  
Metal Free ◽  
Acceptor Complex ◽  
Catalyst Free ◽  
Donor Acceptor ◽  
Radical Cascade

A metal- and catalyst-free photoinduced radical cascade hydroalkylation of 1,7-enynes has been disclosed. The process is triggered by a SET event involving a photoexcited electron-donor-aceptor complex between NHPI ester and Hantzsch ester, which decomposes to afford a tertiary radical that is readily trapped by the enyne. <a>The method provides an operationally simple, robust and step-economical approach to the construction of diversely functionalized dihydroquinolinones bearing quaternary-centers. A sequential one-pot hydroalkylation-isomerization approach is also allowed giving access to a family of quinolinones. A wide substrate scope and high functional group tolerance was observed in both approaches</a>.

Dual Nickel/Palladium-Catalyzed Reductive Cross-Coupling Reactions Between Two Phenol Derivatives

2020 ◽  
Author(s):  
Baojian Xiong ◽  
Yue Li ◽  
Yin Wei ◽  
Søren Kramer ◽  
Zhong Lian
Keyword(s):  
Functional Group ◽  
Low Cost ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Phenol Derivatives ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed ◽  
One Step ◽  
Aryl Tosylates ◽  
Low Sensitivity

Cross-coupling between substrates that can be easily derived from phenols is highly attractive due to the abundance and low cost of phenols. Here, we report a dual nickel/palladium-catalyzed reductive cross-coupling between aryl tosylates and aryl triflates; both substrates can be accessed in just one step from readily available phenols. The reaction has a broad functional group tolerance and substrate scope (>60 examples). Furthermore, it displays low sensitivity to steric effects demonstrated by the synthesis of a 2,2’disubstituted biaryl and a fully substituted aryl product. The widespread presence of phenols in natural products and pharmaceuticals allow for straightforward late-stage functionalization, illustrated with examples such as Ezetimibe and tyrosine. NMR spectroscopy and DFT calculations indicate that the nickel catalyst is responsible for activating the aryl triflate, while the palladium catalyst preferentially reacts with the aryl tosylate.

Effects of Wet Chemical Oxidation on Surface Functionalization and Morphology of Highly Oriented Pyrolytic Graphite

2020 ◽  
Author(s):  
Mikhail Trought ◽  
Isobel Wentworth ◽  
Timothy Leftwich ◽  
Kathryn Perrine
Keyword(s):  
Surface Functionalization ◽  
Functional Group ◽  
Pyrolytic Graphite ◽  
Surface Oxidation ◽  
Chemical Oxidation ◽  
Synthesis Methods ◽  
Acid Solutions ◽  
Highly Oriented Pyrolytic Graphite ◽  
Wet Chemical ◽  
Surface Morphologies

The knowledge of chemical functionalization for area selective deposition (ASD) is crucial for designing the next generation heterogeneous catalysis. Surface functionalization by oxidation was studied on the surface of highly oriented pyrolytic graphite (HOPG). The HOPG surface was exposed to with various concentrations of two different acids (HCl and HNO3). We show that exposure of the HOPG surface to the acid solutions produce primarily the same -OH functional group and also significant differences the surface topography. Mechanisms are suggested to explain these strikingly different surface morphologies after surface oxidation. This knowledge can be used to for ASD synthesis methods for future graphene-based technologies.

Catalytic Synthesis of Cyclic Guanidines via Hydrogen Atom Transfer and Radical-Polar Crossover

2020 ◽  
Author(s):  
Shunya Ohuchi ◽  
Hiroki Koyama ◽  
Hiroki Shigehisa
Keyword(s):  
Hydrogen Atom ◽  
Functional Group ◽  
Hydrogen Atom Transfer ◽  
Catalytic Synthesis ◽  
Membered Ring ◽  
Biologically Active ◽  
Atom Transfer ◽  
Powerful Method ◽  
Protective Groups ◽  
The Common

A catalytic synthesis of cyclic guanidines, which are found in many biologically active compounds and natu-ral products, was developed, wherein transition-metal hydrogen atom transfer and radical-polar crossover were employed. This mild and functional-group tolerant process enabled the cyclization of alkenyl guanidines bearing common protective groups, such as Cbz and Boc. This powerful method not only provided the common 5- and 6-membered rings but also an unusual 7-membered ring. The derivatization of the products afforded various heterocycles. We also investigated the se-lective cyclization of mono-protected or hetero-protected (TFA and Boc) alkenyl guanidines and their further derivatiza-tions.

Design, 22-step synthesis, and evaluation of highly potent D-ring modified and linker-equipped analogs of spongistatin 1

2018 ◽  
Author(s):  
James Leighton ◽  
Linda M. Suen ◽  
Makeda A. Tekle-Smith ◽  
Kevin S. Williamson ◽  
Joshua R. Infantine ◽  
...  
Keyword(s):  
Targeted Delivery ◽  
Functional Group ◽  
Human Cancer ◽  
Natural Sources ◽  
Spongistatin 1 ◽  
Human Cancer Cell Lines ◽  
Drug Conjugates ◽  
Attractive Candidate ◽  
Complex Fragment ◽  
Antibody Drug

With an average GI50 value against the NCI panel of 60 human cancer cell lines of 0.12 nM, spongistatin 1 is among the most potent anti-proliferative agents ever discovered rendering it an attractive candidate for development as a payload for antibody-drug conjugates and other targeted delivery approaches. It is unavailable from natural sources and its size and complex stereostructure render chemical synthesis highly time- and resource-intensive, however, and its development requires more efficient and step-economical synthetic access. Using novel and uniquely enabling direct complex fragment coupling alkallyl- and crotylsilylation reactions, we have developed a 22-step synthesis of a rationally designed D-ring modified analog of spongistatin 1 that is equipotent with the natural product, and have used that synthesis to establish that the C(15) acetate may be replaced with a linker functional group-bearing ester with only minimal reductions in potency.<br><div><br></div>

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