scholarly journals Dual-functional cobalt catalyst enables electrocatalytic allylic C–H alkylation

2021 ◽  
Author(s):  
Ming Chen ◽  
Zheng-Jian Wu ◽  
Jinshuai Song ◽  
Hai-Chao Xu
Keyword(s):  
Value Added ◽  
Synthetic Methods ◽  
Radical Mechanism ◽  
Alkylation Reaction ◽  
Coupling Reactions ◽  
Carbon Nucleophiles ◽  
Noble Metal Catalysts ◽  
Cross Coupling Reactions ◽  
Dual Functional ◽  
Chemical Oxidants

Transition metal-catalyzed allylic substitution reactions of pre-activated allylation agents with nucleophiles are extensively studied synthetic methods that have enjoyed widespread applications in organic synthesis. The direct alkylation of allylic C–H bonds with nucleophiles, which minimizes pre-functionalization and converts inexpensive, abundantly available materials to value-added alkenyl-substituted products, remains challenging. Current methods generally involve C–H activation, require the use of noble-metal catalysts and stoichiometric chemical oxidants, and often show limited scope. Here we report an electrocatalytic allylic C–H alkylation reaction with carbon nucleophiles employing an easily available cobalt-salen complex as the molecular catalyst. These C(sp3)–H/C(sp3)–H cross-coupling reactions proceed through H2 evolution and require no external chemical oxidants. Importantly, the mild conditions and radical mechanism ensure excellent functional group tolerance and substrate compatibility with both linear and branched terminal alkenes. The synthetic utility of the electrochemical method is highlighted by its scalability (up to 200 mmol scale) and its successful application in the late-stage functionalization of complex structures.

Palladium-catalyzed C–H activation/C–C cross-coupling reactions via electrochemistry

2017 ◽  
Vol 53 (90) ◽  
pp. 12189-12192 ◽  
Author(s):  
Cong Ma ◽  
Chuan-Qi Zhao ◽  
Yi-Qian Li ◽  
Li-Pu Zhang ◽  
Xue-Tao Xu ◽  
...  
Keyword(s):  
Anodic Oxidation ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Chemical Oxidants ◽  
Palladium Catalyzed

Palladium-catalyzed C(sp2)–H methylation and acylation via anodic oxidation have been developed to avoid the use of stoichiometric chemical oxidants.

New Synthesis of Dibenzofulvenes by Palladium-Catalyzed Double Cross-Coupling Reactions

2012 ◽  
Vol 65 (9) ◽  
pp. 1277 ◽  
Author(s):  
Masaki Shimizu ◽  
Ikuhiro Nagao ◽  
Shin-ichi Kiyomoto ◽  
Tamejiro Hiyama
Keyword(s):  
Cross Coupling ◽  
Synthetic Methods ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
New Synthesis ◽  
Palladium Catalyzed ◽  
Double Cross

Palladium-catalyzed double cross-coupling reactions of 1,1-bis(pinacolato)borylalk-1-enes with 2,2′-dibromobiaryls and of 9-stannafluorenes with 1,1-dibromoalk-1-enes have been demonstrated to serve as new synthetic methods for dibenzofulvenes.

An Old Dog with New Tricks: Enjoin Wolff–Kishner Reduction for Alcohol Deoxygenation and C–C Bond Formations

Synlett ◽  
2019 ◽  
Vol 30 (13) ◽  
pp. 1508-1524 ◽  
Author(s):  
Chao-Jun Li ◽  
Jianlin Huang ◽  
Xi-Jie Dai ◽  
Haining Wang ◽  
Ning Chen ◽  
...  
Keyword(s):  
Classical Method ◽  
Cross Coupling ◽  
Conjugate Addition ◽  
Alkylation Reaction ◽  
Addition Reactions ◽  
Coupling Reactions ◽  
Chemical Transformations ◽  
Strong Base ◽  
Type Reaction ◽  
Cross Coupling Reactions

The Wolff–Kishner reduction, discovered in the early 1910s, is a fundamental and effective tool to convert carbonyls into methylenes via deoxygenation under strongly basic conditions. For over a century, numerous valuable chemical products have been synthesized by this classical method. The reaction proceeds via the reversible formation of hydrazone followed by deprotonation with the strong base to give an N-anionic intermediate, which affords the deoxygenation product upon denitrogenation and protonation. By examining the mechanistic pathway of this century old classical carbonyl deoxygenation, we envisioned and subsequently developed two unprecedented new types of chemical transformations: a) alcohol deoxygenation and b) C–C bond formations with various electrophiles including Grignard-type reaction, conjugate addition, olefination, and diverse cross-coupling reactions.1 Introduction2 Background3 Alcohol Deoxygenation3.1 Ir-Catalyzed Alcohol Deoxygenation3.2 Ru-Catalyzed Alcohol Deoxygenation3.3 Mn-Catalyzed Alcohol Deoxygenation4 Grignard-Type Reactions4.1 Ru-Catalyzed Addition of Hydrazones with Aldehydes and Ketones4.2 Ru-Catalyzed Addition of Hydrazone with Imines4.3 Ru-Catalyzed Addition of Hydrazone with CO2 4.4 Fe-Catalyzed Addition of Hydrazones5 Conjugate Addition Reactions5.1 Ru-Catalyzed Conjugate Addition Reactions5.2 Fe-Catalyzed Conjugate Addition Reactions6 Cross-Coupling Reactions6.1 Ni-Catalyzed Negishi-type Coupling6.2 Pd-Catalyzed Tsuji–Trost Alkylation Reaction7 Other Reactions7.1 Olefination7.2 Heck-Type Reaction7.3 Ullmann-Type Reaction8 Conclusion and Outlook

scholarly journals Tailored cobalt-salen complexes enable electrocatalytic intramolecular allylic C–H functionalizations

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chen-Yan Cai ◽  
Zheng-Jian Wu ◽  
Ji-Ying Liu ◽  
Ming Chen ◽  
Jinshuai Song ◽  
...  
Keyword(s):  
Functional Groups ◽  
Organic Synthesis ◽  
Functional Group ◽  
Radical Mechanism ◽  
Chemical Modifications ◽  
Noble Metal Catalysts ◽  
Salen Complexes ◽  
Chemical Oxidants ◽  
Ring Structures ◽  
Efficient Coupling

AbstractOxidative allylic C–H functionalization is a powerful tool to streamline organic synthesis as it minimizes the need for functional group activation and generates alkenyl-substituted products amenable to further chemical modifications. The intramolecular variants can be used to construct functionalized ring structures but remain limited in scope and by their frequent requirement for noble metal catalysts and stoichiometric chemical oxidants. Here we report an oxidant-free, electrocatalytic approach to achieve intramolecular oxidative allylic C–H amination and alkylation by employing tailored cobalt-salen complexes as catalysts. These reactions proceed through a radical mechanism and display broad tolerance of functional groups and alkene substitution patterns, allowing efficient coupling of di-, tri- and even tetrasubstituted alkenes with N- and C-nucleophiles to furnish high-value heterocyclic and carbocyclic structures.

scholarly journals Mechanochemical synthesis of magnesium-based carbon nucleophiles in air and their use in organic synthesis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Rina Takahashi ◽  
Anqi Hu ◽  
Pan Gao ◽  
Yunpeng Gao ◽  
Yadong Pang ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Mechanochemical Synthesis ◽  
Nucleophilic Addition ◽  
Reaction Times ◽  
Grignard Reagents ◽  
Coupling Reactions ◽  
One Pot ◽  
Carbon Nucleophiles ◽  
Cross Coupling Reactions ◽  
Solvent Free Conditions

AbstractSince the discovery of Grignard reagents in 1900, the nucleophilic addition of magnesium-based carbon nucleophiles to various electrophiles has become one of the most powerful, versatile, and well-established methods for the formation of carbon−carbon bonds in organic synthesis. Grignard reagents are typically prepared via reactions between organic halides and magnesium metal in a solvent. However, this method usually requires the use of dry organic solvents, long reaction times, strict control of the reaction temperature, and inert-gas-line techniques. Despite the utility of Grignard reagents, these requirements still represent major drawbacks from both an environmental and an economic perspective, and often cause reproducibility problems. Here, we report the general mechanochemical synthesis of magnesium-based carbon nucleophiles (Grignard reagents in paste form) in air using a ball milling technique. These nucleophiles can be used directly for one-pot nucleophilic addition reactions with various electrophiles and nickel-catalyzed cross-coupling reactions under solvent-free conditions.

scholarly journals Synthesis of Conjugated Dienes in Natural Compounds

Catalysts ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 86
Author(s):  
Geoffrey Dumonteil ◽  
Sabine Berteina-Raboin
Keyword(s):  
Total Synthesis ◽  
Cross Coupling ◽  
Natural Compounds ◽  
Conjugated Dienes ◽  
Synthetic Methods ◽  
Coupling Reactions ◽  
Conjugated Diene ◽  
Cross Coupling Reactions

This review describes the various synthetic methods commonly used to obtain molecules possessing conjugated dienes. We focus on methods involving cross-coupling reactions using various metals such as nickel, palladium, ruthenium, cobalt, cobalt/zinc, manganese, zirconium, or iron, mainly through examples that aimed to access natural molecules or their analogues. Among the natural molecules covered in this review, we discuss the total synthesis of a phytohormone, Acid Abscisic (ABA), carried out by our team involving the development of a conjugated diene chain.

scholarly journals Green Synthesis of Pd Nanoparticles for Sustainable and Environmentally Benign Processes

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1258
Author(s):  
Oriana Piermatti
Keyword(s):  
Green Synthesis ◽  
Low Cost ◽  
Pd Nanoparticles ◽  
Synthetic Methods ◽  
High Catalytic Activity ◽  
Coupling Reactions ◽  
Stabilizing Agents ◽  
Cross Coupling Reactions ◽  
Green Approach ◽  
Wide Range

Among transition metal nanoparticles, palladium nanoparticles (PdNPs) are recognized for their high catalytic activity in a wide range of organic transformations that are of academic and industrial importance. The increased interest in environmental issues has led to the development of various green approaches for the preparation of efficient, low-cost and environmentally sustainable Pd-nanocatalysts. Environmentally friendly solvents, non-toxic reducing reagents, biodegradable capping and stabilizing agents and energy-efficient synthetic methods are the main aspects that have been taken into account for the production of Pd nanoparticles in a green approach. This review provides an overview of the fundamental approaches used for the green synthesis of PdNPs and their catalytic application in sustainable processes as cross-coupling reactions and reductions with particular attention afforded to the recovery and reuse of the palladium nanocatalyst, from 2015 to the present.

An Overview of the Chemistry and Pharmacological Potentials of Furanones Skeletons

2019 ◽  
Vol 23 (14) ◽  
pp. 1581-1599 ◽  
Author(s):  
Zahra Hosseinzadeh ◽  
Ali Ramazani
Keyword(s):  
Solid Phase ◽  
Wide Spectrum ◽  
Biological Effects ◽  
Review Article ◽  
New Drugs ◽  
Synthetic Methods ◽  
Phase Method ◽  
Coupling Reactions ◽  
Significant Group ◽  
Cross Coupling Reactions

The furanone structure, a significant group of heterocyclic compounds, is frequently found in natural products that are exhibiting striking pharmacological effects and a growing field of research. They have a wide spectrum of pharmaceutical activity: anticataract, anticancer, antibacterial, anti-inflammatory, anticonvulsant. This review article presents a summary of natural furanones, synthetic methods, and the biological effects of these important compounds. Solid-phase method, cross-coupling reactions, Maillard-type reaction, the cycloaddition of alcohol and phenyl nitrile oxide, and side-chain modifications are some types of reactions for the preparation of furanone derivatives. Methods of preparation and pharmacological activities of furanone skeletons that are discussed in this review article will help the medicinal chemists to design and execute novel procedures towards finding new drugs.

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