scholarly journals Copper-catalyzed O-alkenylation of phosphonates

2020 ◽  
Vol 16 ◽  
pp. 611-615 ◽  
Author(s):  
Nuria Vázquez-Galiñanes ◽  
Mariña Andón-Rodríguez ◽  
Patricia Gómez-Roibás ◽  
Martín Fañanás-Mastral
Keyword(s):  
Copper Catalysis ◽  
Selective Transfer ◽  
Iodonium Salts ◽  
Mild Conditions ◽  
Wide Range ◽  
Dialkyl Phosphonates

Copper catalysis allows the direct oxygen alkenylation of dialkyl phosphonates with alkenyl(aryl)iodonium salts with selective transfer of the alkenyl group. This novel methodology proceeds with a wide range of phosphonates under mild conditions and gives straightforward access to valuable enol phosphonates in very good yields.

Double Ring-Closing Approach for the Synthesis of 2,3,6,7-Substituted Anthracene Derivatives

2020 ◽  
Author(s):  
Birgit Meindl ◽  
Katharina Pfennigbauer ◽  
Berthold Stöger ◽  
Martin Heeney ◽  
Florian Glöcklhofer
Keyword(s):  
Wittig Reaction ◽  
Condensation Reaction ◽  
Synthetic Methods ◽  
Anthracene Derivative ◽  
Double Ring ◽  
Mild Conditions ◽  
Wide Range ◽  
Anthracene Derivatives

Anthracene derivatives have been used for a wide range of applications and many different synthetic methods for their preparation have been developed. However, despite continued synthetic efforts, introducing substituents in some positions has remained difficult. Here we present a method for the synthesis of 2,3,6,7-substituted anthracene derivatives, one of the most challenging anthracene substitution patterns to obtain. The method is exemplified by the preparation of 2,3,6,7-anthracenetetracarbonitrile and employs a newly developed, stable protected 1,2,4,5-benzenetetracarbaldehyde as the precursor. The precursor can be obtained in two scalable synthetic steps from 2,5-dibromoterephthalaldehyde and is converted into the anthracene derivative by a double intermolecular Wittig reaction under very mild conditions followed by a deprotection and intramolecular double ring-closing condensation reaction. Further modification of the precursor is expected to enable the introduction of additional substituents in other positions and may even enable the synthesis of fully substituted anthracene derivatives by the presented approach.<br>

scholarly journals Photocatalytic three-component asymmetric sulfonylation via direct C(sp3)-H functionalization

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shi Cao ◽  
Wei Hong ◽  
Ziqi Ye ◽  
Lei Gong
Keyword(s):  
Asymmetric Catalysis ◽  
Organic Synthesis ◽  
Photochemical Reaction ◽  
Low Cost ◽  
Bioactive Molecules ◽  
Atom Economy ◽  
Mild Conditions ◽  
Wide Range ◽  
Unsaturated Carbonyl Compound ◽  
Direct Functionalization

AbstractThe direct and selective C(sp3)-H functionalization of cycloalkanes and alkanes is a highly useful process in organic synthesis owing to the low-cost starting materials, the high step and atom economy. Its application to asymmetric catalysis, however, has been scarcely explored. Herein, we disclose our effort toward this goal by incorporation of dual asymmetric photocatalysis by a chiral nickel catalyst and a commercially available organophotocatalyst with a radical relay strategy through sulfur dioxide insertion. Such design leads to the development of three-component asymmetric sulfonylation involving direct functionalization of cycloalkanes, alkanes, toluene derivatives or ethers. The photochemical reaction of a C(sp3)-H precursor, a SO2 surrogate and a common α,β-unsaturated carbonyl compound proceeds smoothly under mild conditions, delivering a wide range of biologically interesting α-C chiral sulfones with high regio- and enantioselectivity (>50 examples, up to >50:1 rr and 95% ee). This method is applicable to late-stage functionalization of bioactive molecules, and provides an appealing access to enantioenriched compounds starting from the abundant hydrocarbon compounds.

scholarly journals Continuous-Flow Synthesis of Thioureas, Enabled by Aqueous Polysulfide Solution

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 303
Author(s):  
András Gy. Németh ◽  
Renáta Szabó ◽  
György Orsy ◽  
István M. Mándity ◽  
György M. Keserű ◽  
...  
Keyword(s):  
Multicomponent Reaction ◽  
Continuous Flow ◽  
Flow Synthesis ◽  
Mild Conditions ◽  
Wide Range ◽  
Simple Filtration

We have developed the continuous-flow synthesis of thioureas in a multicomponent reaction starting from isocyanides, amidines, or amines and sulfur. The aqueous polysulfide solution enabled the application of sulfur under homogeneous and mild conditions. The crystallized products were isolated by simple filtration after the removal of the co-solvent, and the sulfur retained in the mother liquid. Presenting a wide range of thioureas synthesized by this procedure confirms the utility of the convenient continuous-flow application of sulfur.

Visible light-photocatalysed carbazole synthesis via a formal (4+2) cycloaddition of indole-derived bromides and alkynes

2016 ◽  
Vol 52 (29) ◽  
pp. 5128-5131 ◽  
Author(s):  
Zhi-Guang Yuan ◽  
Qiang Wang ◽  
Ang Zheng ◽  
Kai Zhang ◽  
Liang-Qiu Lu ◽  
...  
Keyword(s):  
Visible Light ◽  
Mild Conditions ◽  
Wide Range

We have developed an unprecedented route to carbazole by a visible light-photocatalysed formal (4+2) cycloaddition of indole-derived bromides and alkynes. Using this method, a wide range of highly functionalised carbazoles were produced in good yields under mild conditions.

Organic–inorganic hybrids having a talc-like structure as suitable hosts to guest a wide range of species

2018 ◽  
Vol 47 (9) ◽  
pp. 2925-2932 ◽  
Author(s):  
J. Brendlé
Keyword(s):  
Hybrid Materials ◽  
Sol Gel ◽  
Step Method ◽  
Mild Conditions ◽  
Condensation Reactions ◽  
Wide Range ◽  
Sol Gel Process ◽  
Hydrolysis And Condensation ◽  
One Step

The sol–gel process involving hydrolysis and condensation reactions is an attractive way to form siloxane based hybrid materials since it is a one-step method performed under mild conditions.

Convenient Synthesis of Fluorescent Chromeno[4,3-d]pyrimidines from Electron-Deficient 3-Vinylchromones

Synthesis ◽  
2019 ◽  
Vol 52 (01) ◽  
pp. 40-50 ◽  
Author(s):  
Nikita M. Chernov ◽  
Roman V. Shutov ◽  
Anastasia E. Potapova ◽  
Igor P. Yakovlev
Keyword(s):  
Stokes Shift ◽  
Mild Conditions ◽  
Convenient Synthesis ◽  
Acid Fragment ◽  
Wide Range ◽  
Powerful Approach ◽  
Reaction Proceeds ◽  
Electron Withdrawing Group ◽  
Blue Range ◽  
Acetic Acids

We report an easy and powerful approach to the synthesis of novel chromeno[4,3-d]pyrimidine-5-acetic acids through ANRORC reaction of electron-deficient 3-vinylchromones and 1,3-N,N-binucleophiles. The reaction proceeds under mild conditions (EtOH, rt) and is applicable to a wide range of substrates. The described compounds show fluorescence in the violet-blue range (390–460 nm) with Stokes shift of 40–80 nm and moderate quantum yield (0.15–0.20). As the electron-withdrawing group is conserved in the form of an acetic acid fragment, these compounds may readily be functionalized or conjugated to a required substrate for (bio)analytical purposes.

Palladium-Catalyzed Cyanation under Mild Conditions: A Case Study to Discover Appropriate Substrates among Halides and Pseudohalides

Synlett ◽  
2020 ◽  
Vol 31 (16) ◽  
pp. 1629-1633
Author(s):  
K. Sunil ◽  
Merla Arjuna Rajendra ◽  
Ayyiliath Meleveetil Sajith ◽  
Muthipeedika Nibin Joy ◽  
Vasiliy A. Bakulev ◽  
...  
Keyword(s):  
Environmentally Benign ◽  
Potassium Hexacyanoferrate ◽  
Mild Conditions ◽  
Suitable Substrate ◽  
Wide Range ◽  
Palladium Catalyzed

A case study has been effectively carried out to identify a suitable substrate among halides and pseudohalides for the palladium-catalyzed cyanation reactions under mild conditions. Among the various substrates considered for evaluation, aryl pentafluorobenzenesulfonates and nonaflates were identified to be the best substrates when compared to corresponding halides and pseudohalides. The substoichiometric use of nontoxic, environmentally benign potassium hexacyanoferrate as a cyanide source and exceptionally milder conditions further highlights the significance of the protocol developed. A wide range of electronically biased and sterically challenging substrates provided the corresponding the nitriles in good to excellent yields.

scholarly journals New simple synthesis of ring-fused 4-alkyl-4H-3,1-benzothiazine-2-thiones: Direct formation from carbon disulfide and (E)-3-(2-aminoaryl)acrylates or (E)-3-(2-aminoaryl)acrylonitriles

2013 ◽  
Vol 9 ◽  
pp. 460-466 ◽  
Author(s):  
Qiuping Ding ◽  
Yuqing Lin ◽  
Guangni Ding ◽  
Fumin Liao ◽  
Xiaoyan Sang ◽  
...  
Keyword(s):  
Carbon Disulfide ◽  
Efficient Method ◽  
Simple Synthesis ◽  
Metal Catalyst ◽  
Mild Conditions ◽  
Wide Range ◽  
Direct Formation

A new simple and efficient method to construct ring-fused 4-alkyl-4H-3,1-benzothiazine-2-thione derivatives has been developed from carbon disulfide and (E)-3-(2-aminoaryl)acrylates or (E)-3-(2-aminoaryl)acrylonitriles under mild conditions, without the need for a metal catalyst. The newly developed method tolerates a wide range of substrates in moderate to excellent yields. Moreover, this method is advantageous over previous ones for the easy synthesis of reactants.

Additive- and Oxidant-Free Expedient Synthesis of Benzimidazoles Catalyzed by Cobalt Nanocomposites on N-Doped Carbon

Synlett ◽  
2019 ◽  
Vol 30 (03) ◽  
pp. 319-324 ◽  
Author(s):  
Zhaozhan Wang ◽  
Tao Song ◽  
Yong Yang
Keyword(s):  
Functional Group ◽  
Direct Synthesis ◽  
Biologically Active ◽  
One Pot ◽  
Mild Conditions ◽  
Wide Range ◽  
High Yields

A one-pot direct synthesis of a wide range of biologically active benzimidazoles through coupling of phenylenediamines and aldehydes catalyzed by a highly recyclable nonnoble cobalt nanocomposite was developed. A broad set of benzimidazoles can be efficiently synthesized in high yields and with good functional-group tolerance under additive- and oxidant-free mild conditions. The catalyst can be easily recycled for successive uses, and the process permits gram-scale syntheses of benzimidazoles.

scholarly journals 2-Aminoquinazolines by Chan–Evans–Lam Coupling of Guanidines with (2-Formylphenyl)boronic Acids

Synlett ◽  
2020 ◽  
Vol 31 (15) ◽  
pp. 1507-1510
Author(s):  
Aigars Jirgensons ◽  
Vitalii V. Solomin ◽  
Alberts Seins
Keyword(s):  
Boronic Acids ◽  
New Method ◽  
Mild Conditions ◽  
Wide Range

A new method is presented for the synthesis of 2-aminoquinazolines, which is based on a Chan–Evans–Lam coupling of (2-formylphenyl)boronic acids with guanidines. Relatively mild conditions involving the use of inexpensive CuI as a catalyst and methanol as a solvent permit the application of the method to a wide range of substrates. Nonsubstituted, N-monosubstituted, and N,N-disubstituted guanidines can be used as reactants to give the corresponding 2-aminoquinazolines in moderate yields from readily available (2-formylphenyl)boronic acids.

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