Recent Developments in Transition Metal-Free Cross-Dehydrogenative Coupling Reactions for C-C bond formation

2020 ◽  
Author(s):  
Aanchal Batra ◽  
Kamal Nain Singh
Keyword(s):  
Transition Metal ◽  
Bond Formation ◽  
Coupling Reactions ◽  
Metal Free ◽  
Dehydrogenative Coupling ◽  
Recent Developments

Transition-Metal-Free Catalysis for the Reductive ­Functionalization of CO2 with Amines

Synlett ◽  
2018 ◽  
Vol 29 (05) ◽  
pp. 548-555 ◽  
Author(s):  
Liang-Nian He ◽  
Xiao-Fang Liu ◽  
Xiao-Ya Li ◽  
Chang Qiao
Keyword(s):  
Transition Metal ◽  
Energy Content ◽  
Bond Formation ◽  
Energy Storage Materials ◽  
One Pot ◽  
Metal Free ◽  
Recent Developments ◽  
Electron Reduction ◽  
Reduction Of Co2 ◽  
Hierarchical Reduction

Reductive functionalization of CO2 with amines and a reductant, which combines both reduction of CO2 and C–N bond formation in one pot to produce versatile chemicals and energy-storage materials such as formamides, aminals, and methylamines that are usually derived from petroleum feedstock, would be appealing and promising. Herein, we give a brief review on recent developments in the titled CO2 chemistry by employing transition-metal-free catalysis, which can be catalogued as below according to the diversified energy content of the products, that is formamides, aminals, and methylamines being consistent with 2-, 4-, and 6-electron reduction of CO2, respectively. Notably, hierarchical reduction of CO2 with amines to afford at least two products, for example, formamides and methylamines, could be realized with the same catalyst through tuning the hydrosilane type, reaction temperature, or CO2 pressure. Finally, the opportunities and challenges of the reductive functionalization of CO2 with amines are also highlighted.1 Introduction2 2-Electron Reduction of CO2 to Formamide3 6-Electron Reduction of CO2 to Methylamine4 4-Electron Reduction of CO2 to Aminal5 Hierarchical Reduction of CO2 with Amines6 Conclusion

Recent Developments in Transition-Metal-Free Functionalization and Derivatization Reactions of Pyridines

Synlett ◽  
2020 ◽  
Author(s):  
Lei Jiao ◽  
Fei-Yu Zhou
Keyword(s):  
Transition Metal ◽  
Structural Motif ◽  
Metal Exchange ◽  
Coupling Reactions ◽  
Phosphonium Salts ◽  
Metal Free ◽  
Radical Coupling ◽  
In Situ Activation ◽  
Recent Developments

AbstractPyridine is an important structural motif that is prevalent in natural products, drugs, and materials. Methods that functionalize and derivatize pyridines have gained significant attention. Recently, a large number of transition-metal-free reactions have been developed. In this review, we provide a brief summary of recent advances in transition-metal-free functionalization and derivatization reactions of pyridines, categorized according to their reaction modes.1 Introduction2 Metalated Pyridines as Nucleophiles2.1 Deprotonation2.2 Halogen–Metal exchange3 Activated Pyridines as Electrophiles3.1 Asymmetric 2-Allylation by Chiral Phosphite Catalysis3.2 Activation of Pyridines by a Bifunctional Activating Group3.3 Alkylation of Pyridines by 1,2-Migration3.4 Alkylation of Pyridines by [3+2] Addition3.5 Pyridine Derivatization by Catalytic In Situ Activation Strategies3.6 Reactions via Heterocyclic Phosphonium Salts4 Radical Reactions for Pyridine Functionalization4.1 Pyridine Functionalization through Radical Addition Reactions4.2 Pyridine Functionalization through Radical–Radical Coupling Reactions5 Derivatization of Pyridines through the Formation of Meisenheimer-Type Pyridyl Anions6 Conclusion

Transition-Metal-Free Acylation of Quinolines and Isoquinolines with Arylmethanols via Oxidative Cross-Dehydrogenative Coupling Reactions

Synlett ◽  
2016 ◽  
Vol 27 (15) ◽  
pp. 2241-2245 ◽  
Author(s):  
Mehdi Adib ◽  
Rahim Pashazadeh ◽  
Saideh Rajai-Daryasarei ◽  
Roya Kabiri ◽  
Seyed Gohari
Keyword(s):  
Transition Metal ◽  
Coupling Reactions ◽  
Metal Free ◽  
Dehydrogenative Coupling

Iron-Catalyzed Aerobic Oxidative Cross-Dehydrogenative C(sp3)–H/X–H (X = C, N, S) Coupling Reactions

Synlett ◽  
2020 ◽  
Vol 31 (18) ◽  
pp. 1753-1759
Author(s):  
Da-Zhen Xu ◽  
Ren-Ming Hu ◽  
Yi-Huan Lai
Keyword(s):  
Molecular Oxygen ◽  
Bond Formation ◽  
Research Topic ◽  
Synthetic Chemistry ◽  
Coupling Reactions ◽  
Iron Salts ◽  
Dehydrogenative Coupling ◽  
Recent Developments ◽  
Direct Functionalization ◽  
Made In

The direct functionalization of C(sp3)–H bonds is an attractive research topic in organic synthetic chemistry. The cross-dehydrogenative coupling (CDC) reaction provides a simple and powerful tool for the construction of C–C and C–heteroatom bonds. Recently, some progress has been made in the iron-catalyzed aerobic oxidative CDC reactions. Here, we present recent developments in the direct functionalization of C(sp3)–H bonds catalyzed by simple iron salts with molecular oxygen as the terminal oxidant.1 Introduction2 C(sp3)–C Bond Formation3 C(sp3)–N Bond Formation4 C(sp3)–S(Se) Bond Formation5 Conclusion and Outlook

Transition-metal-free direct cross-dehydrogenative coupling reactions of quinolinones with ethers

2020 ◽  
Vol 61 (4) ◽  
pp. 151426
Author(s):  
Gang Wang ◽  
Jun-Tao Wang ◽  
Bing Zhao ◽  
Huan Chen ◽  
Pan-Ke Zhang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Coupling Reactions ◽  
Metal Free ◽  
Dehydrogenative Coupling ◽  
Direct Cross

scholarly journals Recent Advances in Transition-Metal-Catalyzed, Directed Aryl C–H/N–H Cross-Coupling Reactions

Synthesis ◽  
2017 ◽  
Vol 49 (20) ◽  
pp. 4586-4598 ◽  
Author(s):  
Martyn Henry ◽  
Mohamed Mostafa ◽  
Andrew Sutherland
Keyword(s):  
Transition Metal ◽  
Bond Formation ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Short Review ◽  
Coupling Reactions ◽  
Dehydrogenative Coupling ◽  
Transition Metal Catalyzed ◽  
Catalyzed Reactions ◽  
Metal Catalyzed

Amination and amidation of aryl compounds using a transition-metal-catalyzed cross-coupling reaction typically involves prefunctionalization or preoxidation of either partner. In recent years, a new class of transition-metal-catalyzed cross-dehydrogenative coupling reaction has been developed for the direct formation of aryl C–N bonds. This short review highlights the substantial progress made for ortho-C–N bond formation via transition-metal-catalyzed chelation-directed aryl C–H activation and gives an overview of the challenges that remain for directed meta- and para-selective reactions.1 Introduction2 Intramolecular C–N Cross-Dehydrogenative Coupling2.1 Nitrogen Functionality as Both Coupling Partner and Directing Group2.2 Chelating-Group-Directed Intramolecular C–N Bond Formation3 Intermolecular C–N Cross-Dehydrogenative Coupling3.1 ortho-C–N Bond Formation3.1.1 Copper-Catalyzed Reactions3.1.2 Other Transition-Metal-Catalyzed Reactions3.2 meta- and para-C–N Bond Formation4 C–N Cross-Dehydrogenative Coupling of Acidic C–H Bonds5 Conclusions

Developments in Organocatalyzed C(Ar)- C(Ar) Bond formation Reactions via Single Electron Transfer Mechanism: An Overview

2021 ◽  
Vol 08 ◽  
Author(s):  
Lalit Yadav ◽  
Sandeep Chaudhary
Keyword(s):  
Transition Metal ◽  
Organic Synthesis ◽  
Bond Activation ◽  
Bond Formation ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Metal Free ◽  
Cross Coupling Reactions ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

: The formation of new bonds through C-C bond formation is of utmost importance in the synthesis of biologically privileged scaffolds and therapeutic drugs. In recent years, extensive efforts has been done to improve the intermolecular and intramolecular cross-coupling reaction in the simple, mild, efficient, economical, and eco-friendly manner via transition metal-free or organocatalytic direct C-H bond activation methodology. The traditional crosscoupling era continuously shifted to metal-free, organocatalytic, or metal-free cross-dehydrogenative coupling strategies to fast-track the reactions and diminishing the typical purification processes. Therefore, recent advances on the transitionmetal-free, organocatalytic inter- and intra-molecular cross-coupling reactions have been introduced and discussed in the present article. In view of the reaction mechanism, organocatalytic cross-coupling reactions undergo through the radical pathways, radical anionic intermediate which is completely different from traditional transition metal-catalyzed reactions. The exploration of transition metal-free organocatalyzed cross-couplings for direct C-H arylation of arenes has grown significantly, thereby, improving the formation of a wide range of aryl-aryl /aryl-heteroaryl/ heteroaryl-heteroaryl compounds. In the survey, transition metal-free/organocatalytic cross-coupling reactions showed a higher efficiency under simple and mild conditions than the comparative transition metal-catalyzed cross-coupling reactions. However, the higher regioselectivity and chemoselectivity are still far ahead in organocatalytic cross-coupling reactions due to their specific intrinsic mechanistic pathway. The tuning of many parameters such as oxidative states, ligands coordination, and counter anions, etc., which results in the specific direct C-H functionalization with flexible methodology are missing in the transition metal-free cross-coupling reactions. The highly systematic transition metal-catalyzed chemistry is still playing a dominant role over transition metal-free chemistry in organic synthesis. The organocatalyzed transition-metal-free conditions should be more efficient, chemoselective, and regioselective for further potential development and applications in organic synthesis. For the endless pursuit of sustainable chemistry and green chemistry, such transition-metalfree/organocatalytic reactions should be never ceased. Additional curious attention and interest have been developed so far, and chemists are showing their eagerness and talents to uncover the hidden treasure of green chemistry. In this review article, we highlighted the developments of various transition metal-free/organocatalytic C-H bond activation reactions which further encourages the advancement in the development of sustainable C-C coupling reactions and their further applications towards the synthesis of biologically privileged scaffolds and drug molecules.

Transition-Metal-Free Synthetic Strategies for the Cross-Coupling Reactions in Water: A Green Approach

2020 ◽  
Vol 07 ◽  
Author(s):  
Tanmay Chatterjee ◽  
Nilanjana Mukherjee
Keyword(s):  
Transition Metal ◽  
Organic Solvents ◽  
Aqueous Media ◽  
Cross Coupling ◽  
Transition Metal Catalysts ◽  
Synthetic Methods ◽  
Coupling Reactions ◽  
Organic Transformations ◽  
Green Approach ◽  
Dehydrogenative Coupling

Abstract: A natural driving force is always working behind the synthetic organic chemists towards the development of ‘green’ synthetic methodologies for the synthesis of useful classes of organic molecules having potential applications. The majority of the essential classes of organic transformations, including C-C and C-X (X = heteroatom) bond-forming crosscoupling reactions, cross dehydrogenative-coupling (CDC) mostly rely on the requirement of transition-metal catalysts and hazardous organic solvents. Hence, the scope in developing green synthetic strategies by avoiding the use of transitionmetal catalysts and hazardous organic solvents for those important and useful classes of organic transformations is very high. Hence, several attempts are made so far. Water being the most abundant, cheap, and green solvent in the world; numerous synthetic methods have been developed in an aqueous medium. In this review, the development of transitionmetal- free green synthetic strategies for various important classes of organic transformations such as C-C and C-X bondforming cross-coupling, cross dehydrogenative-coupling, and oxidative-coupling in an aqueous media is discussed.

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