Recent Advance in Iminyl-Radical-Triggered C−H and C−C Bond Functionalization of Oxime Esters via 1,5-HAT and β-Carbon Scission

Synthesis ◽  
2021 ◽  
Author(s):  
Le Liu ◽  
Xin-Hua Duan ◽  
Li-Na Guo
Keyword(s):  
High Efficiency ◽  
Short Review ◽  
Hydrogen Atom Transfer ◽  
Chemical Transformations ◽  
Complex Molecules ◽  
Site Specific ◽  
Bond Functionalization ◽  
Similar Chemical ◽  
Direct Functionalization ◽  
High Bond

Direct functionalization of C(sp3)−H and C(sp3)−C(sp3) bonds are considered as one of the most valuable synthetic strategies because of their high efficiency and step-economy for rapid assembly of complex molecules. However, the relatively high bond disassociation energies (BDEs) and similar chemical environment lead to large obstacles in terms of the low reactivity and selectivity. Radical-based strategy was proved to be an efficient approach to overcome these difficulties via hydrogen atom transfer (HAT) process for selective C(sp3)−H functionalization and -carbon scission for C(sp3)−C(sp3) bonds derivatization. Oxime esters have emerged as outstanding precursors of iminyl radicals for versatile chemical transformations. This short review summaries the recent advances in site-specific C(sp3)−H functionalization and C(sp3)−C(sp3) bonds cleavage starting from oxime esters by our group and some others pioneer work, mainly focusing on the reaction design as well as the reaction mechanism.

scholarly journals Recent Advances in Palladium-Catalyzed Bridging C–H Activation by Using Alkenes, Alkynes or Diazo Compounds as Bridging Reagents

Synthesis ◽  
2020 ◽  
Vol 53 (02) ◽  
pp. 238-254
Author(s):  
Fulin Zhang ◽  
Luoting Xin ◽  
Saihu Liao ◽  
Xueliang Huang ◽  
Yinghua Yu
Keyword(s):  
Bond Distance ◽  
Short Review ◽  
Diazo Compounds ◽  
Bond Functionalization ◽  
Migratory Insertion ◽  
Intramolecular Reactions ◽  
Palladium Catalyzed ◽  
Direct Functionalization ◽  
Intermolecular Reactions ◽  
Metal Catalyzed

AbstractTransition-metal-catalyzed direct inert C–H bond functionalization has attracted much attention over the past decades. However, because of the high strain energy of the suspected palladacycle generated via C–H bond palladation, direct functionalization of a C–H bond less than a three-bond distance from a catalyst center is highly challenging. In this short review, we summarize the advances on palladium-catalyzed bridging C–H activation, in which an inert proximal C–H bond palladation is promoted by the elementary step of migratory insertion of an alkene, an alkyne or a metal carbene intermediate.1 Introduction2 Palladium-Catalyzed Alkene Bridging C–H Activation2.1 Intramolecular Reactions2.2 Intermolecular Reactions3 Palladium-Catalyzed Alkyne Bridging C–H Activation3.1 Intermolecular Reactions3.2 Intramolecular Reactions4 Palladium-Catalyzed Carbene Bridging C–H Activation5 Conclusion and Outlook

Advances in C(sp3)–H Bond Functionalization via Radical Processes

Synthesis ◽  
2019 ◽  
Vol 51 (24) ◽  
pp. 4531-4548 ◽  
Author(s):  
Tong Zhang ◽  
Yue-Hua Wu ◽  
Nai-Xing Wang ◽  
Yalan Xing
Keyword(s):  
Free Radicals ◽  
Hydrogen Atom ◽  
Functional Groups ◽  
Organic Molecules ◽  
Functional Group ◽  
Hydrogen Atom Transfer ◽  
Significant Progress ◽  
Bond Functionalization ◽  
Direct Functionalization ◽  
Radical Processes

C(sp3)–H Bonds are the most common structures in organic molecules. In recent years, the direct functionalization of C(sp3)–H bonds has attracted wide attention and made significant progress. This review mainly focuses on C(sp3)–H bond functionalization of alkanes with or without functional groups via radical processes reported since 2017. In particular, three methods of generating free radicals are discussed: the use of a radical initiator such as TBHP or DTBP; photocatalysis, and via 1,5-hydrogen atom transfer (1,5-HAT).1 Introduction2 C(sp3)–H Bond Functionalization of Alkanes3 C(sp3)–H Bond Functionalization of Alkanes with a Functional Group4 Conclusions

Recent Advances in Copper-Catalyzed Radical C–H Bond Activation Using N–F Reagents

Synthesis ◽  
2020 ◽  
Vol 53 (01) ◽  
pp. 51-64
Author(s):  
José María Muñoz-Molina ◽  
Tomás R. Belderrain ◽  
Pedro J. Pérez
Keyword(s):  
Hydrogen Atom ◽  
Bond Activation ◽  
Short Review ◽  
Industrial Applications ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer ◽  
Bond Functionalization ◽  
The Future ◽  
Intramolecular Hydrogen ◽  
Potential Use

This Short Review is aimed at giving an update in the area of copper-catalyzed C–H functionalization involving nitrogen-centered radicals generated from substrates containing N–F bonds. These processes include intermolecular Csp3–H bond functionalization, remote Csp3–H bond functionalization via intramolecular hydrogen atom transfer (HAT), and Csp2–H bond functionalization, which might be of potential use in industrial applications in the future.1 Introduction2 Intermolecular Csp3–H Functionalization3 Remote Csp3–H Functionalization4 Csp2–H Functionalization5 Conclusion

scholarly journals Intermolecular Radical C–H Bond Activation: A Powerful Tool for Late Stage Functionalization

2020 ◽  
Vol 74 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Fabrice Dénès
Keyword(s):  
Bond Activation ◽  
Bond Formation ◽  
Short Review ◽  
Hydrogen Atom Transfer ◽  
Alkyl Halides ◽  
Alternative Methods ◽  
Radical Species ◽  
Complex Molecules ◽  
Recent Developments ◽  
Successful Approach

The synthesis of complex molecules via radical reactions involving carbon–carbon and carbon–heteroatom bonds has become a very successful approach. Radical chemistry has long been dominated by the use of tin-based reagents. Those strongly contributed to the development of the field, allowing one to achieve spectacular transformations, most of which being difficult or impossible to achieve under ionic conditions, and giving access to invaluable kinetics data that paved the way for the development of improved protocols and the design of new synthetic strategies. However, tin reagents and tin byproducts are often toxic and they proved to make purification steps sometimes tedious. In this context, tin-free methods have progressively gained in interest. This short review aims at providing the reader with alternative methods employing C–H bonds in place of the classical alkyl halides to generate, via an intermolecular hydrogen atom transfer (HAT), the radical species. Examples of carbon–carbon and carbon–heteroatom bond formation using this type of C–H bond activation approach will be provided, from early reports to the more recent developments.

The Transient Directing Group Strategy: A New Trend in Transition-Metal-Catalyzed C–H Bond Functionalization

Synthesis ◽  
2017 ◽  
Vol 49 (21) ◽  
pp. 4808-4826 ◽  
Author(s):  
Tatiana Besset ◽  
Qun Zhao ◽  
Thomas Poisson ◽  
Xavier Pannecoucke
Keyword(s):  
Transition Metal ◽  
Bond Activation ◽  
Short Review ◽  
Point Of View ◽  
Bond Functionalization ◽  
Carbonyl Derivatives ◽  
Direct Functionalization ◽  
Directing Group ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

In recent years, the C–H bond activation field has known very fast expansion offering valuable synthetic tools. Consequently, the quest for new approaches to afford atom- and step-economical processes has driven the scientific community to imagine original strategies. In this context, the direct functionalization of substrates by a transition-metal-catalyzed C–H bond activation using a transient directing group has emerged as a promising approach. This short review focuses on the major progress made in this field to provide to the reader an overview of the recent advances.1 Introduction2 From a Historical Point of View3 Functionalization of Carbonyl Derivatives4 Functionalization of Amines Derivatives5 Summary and Outlook

Diversity-Oriented Synthesis of Highly Functionalized Alicycles across Dipolar Cycloaddition/Metathesis Reaction

Synlett ◽  
2021 ◽  
Author(s):  
Loránd Kiss ◽  
Zsanett Benke ◽  
Melinda Nonn ◽  
Attila M. Remete ◽  
Santos Fustero
Keyword(s):  
Amino Acid ◽  
Ring Opening ◽  
Nitrile Oxide ◽  
Amino Acid Derivatives ◽  
Selective Synthesis ◽  
Chemical Transformations ◽  
Bond Functionalization ◽  
Cross Metathesis ◽  
Chlorosulfonyl Isocyanate ◽  
Biological Potential

AbstractThis Account gives an insight into the selective functionalization of some readily available commercial cyclodienes across simple chemical transformations into functionalized small-molecular scaffolds. The syntheses involved selective cycloadditions, followed by ring-opening metathesis (ROM) of the resulting azetidin-2-one derivatives or isoxazoline frameworks and selective cross metathesis (CM) by discrimination of the C=C bonds on the alkenylated heterocycles. The CM protocols have been described when investigated under various conditions with the purpose on exploring chemodifferentiation of the olefin bonds and a study on the access of the corresponding functionalized β-lactam or isoxazoline derivatives is presented. Due to the expanding importance of organofluorine chemistry in drug research as well as of the high biological potential of β-lactam derivatives several illustrative examples to the access of some fluorine-containing molecular entities is also presented in this synopsis.1 Introduction2 Ring C=C Bond Functionalization of Some Cycloalkene β-Amino Acid Derivatives across Chlorosulfonyl Isocyanate Cycloaddition3 Ring C=C Bond Functionalization of Some Cycloalkene β-Amino Acid Derivatives across Nitrile Oxide Cycloaddition4 Ring C=C Bond Functionalization of Some Cycloalkene β-Amino Acid Derivatives across Metathesis5 Functionalization of sSome Cyclodienes across Nitrile Oxide Cycloaddition6 Selective Synthesis of Functionalized Alicycles across Ring-Opening Metathesis7 Selective Synthesis of Functionalized Alicycles through Cross Metathesis8 Summary and Outlook9 List of Abbreviations

Visible-Light Photocatalytic Selective Oxidation of Amine and Sulfide with CsPbBr3 as Photocatalyst

2021 ◽  
Author(s):  
Qiangwen Fan ◽  
Longwei Zhu ◽  
Xuhuai Li ◽  
Huijun Ren ◽  
Haibo Zhu ◽  
...  
Keyword(s):  
Visible Light ◽  
Selective Oxidation ◽  
High Efficiency ◽  
Chemical Transformations ◽  
Inorganic Lead ◽  
Halide Perovskites ◽  
Lead Halide ◽  
Visible Light Photocatalytic

Using readily accessible and high-efficiency photocatalyst for inducing chemical transformations is highly desirable. All inorganic lead halide perovskites (APbX3, X=Cl, Br, I) utilized intensively in photovoltaics on the benefit of...

scholarly journals A Short Review of Lithium-ion Battery Technology

2020 ◽  
pp. 500-507
Author(s):  
Imran Hussain Sardar ◽  
Souren Bhattacharyya
Keyword(s):  
Power Systems ◽  
Lithium Batteries ◽  
Lithium Battery ◽  
High Efficiency ◽  
Lithium Ion ◽  
Short Review ◽  
Consumer Electronics ◽  
Power Sources ◽  
High Specific Energy ◽  
Battery Technology

Lithium batteries are characterized by high specific energy, high efficiency and long life. These unique properties have made lithium batteries the power sources of choice for the consumer electronics market with a production of the order of billions of units per year. These batteries are also expected to find a prominent role as ideal electrochemical storage systems in renewable energy plants, as well as power systems for sustainable vehicles, such as hybrid and electric vehicles. However, scaling up the lithium battery technology for these applications is still problematic since issues such as safety, costs, wide operational temperature and materials availability, are still to be resolved. This review focuses first on the present status of lithium battery technology, then on its near future development and finally it examines important new directions aimed at achieving quantum jumps in energy and power content.

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