bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regio‐Selective CH Functionalization of 7‐Azaindoles
Authors: Kannaboina Prakash , Das Parthasarathi 
Published: October 2022

Abstract
The 7‐azaindole is an important building block in several pharmaceutically important compounds. To develop synthetic, elegant techniques for the functionalization of 7‐azaindole core continues to be an active area of research due to its powerful medicinal properties. There have been significant advances in metal‐catalyzed functionalization of the 7‐azaindole moiety. A collective account of these reactions is presented in this article to showcase the existing landscape of CH functionalization of 7‐azaindoles, to create interest in this field for further development and propagate this strategy for ring substitution reactions of 7‐azaindole systems.
Manganese‐Catalyzed CH Functionalization of Heterocycles
Authors: Liu Zheyuan , Dang Yanfeng 
Published: October 2022

Abstract
Manganese is one of the most prominent candidates for catalysis in looking for novel reactivity, owing to its less toxic, inexpensive, and earth‐abundant nature. In recent decade, manganese‐catalyzed CH functionalization of heterocycles has emerged as a powerful and efficient method in chemical synthesis. These strategies mainly involve CH addition to unsaturated substrates, cascade CH activation/cyclization, and CH alkylation/arylation, which have found great applications in the biochemistry and natural product synthesis. This section summarizes the main advancements of manganese‐catalyzed CH functionalization of heterocycles in homogeneous catalysis.
Iridium‐Catalyzed Asymmetric CH Functionalization
Authors: Shibata Takanori , Pan Shiguang 
Published: October 2022

AbstractIridium catalysis is one of the major synthetic protocols in CH functionalization. In particular, it has been used to realize significant achievements in enantioselective transformations. This article describes Ir‐catalyzed enantioselective reactions initiated by CH bond cleavage. Various CH alkylations using alkenes are mainly discussed as an atom‐economical strategy. As a recent advancement, the introduction of heteroatom functionality by CH activation, such as CH borylation, silylation, and amidation, is also mentioned.
Ruthenium‐Catalyzed Asymmetric CH Functionalization
Authors: Xu Xue , Cui Xin 
Published: October 2022

Abstract
Owing to their cost‐effectiveness among precious metals and easy preparation, ruthenium catalysts have been developed as one class of the major tools for catalytic CH functionalization with a diversified scope of pathways. During the recent decades, asymmetric catalytic systems by chiral ruthenium catalysts have been actively explored for the production of enantiomerically enriched products from inert CH bonds. Through the atom/group transfer pathways, asymmetric hydroxylation, amination, and alkylation reactions of CH bonds have been developed based on the design of various new ligands and catalysts. On the other hand, ruthenium catalysis via metal‐assisted CH cleavage and ruthenacycle intermediates has recently been shown successfully in their asymmetric versions with different strategies. In this article, the development of ruthenium‐catalyzed asymmetric CH bond functionalization reactions will be reviewed. Atom/group transfer pathways are summarized according to the reaction types, including hydroxylation, amination, and alkylation. Subsequently, ruthenium(0)‐catalyzed asymmetric CH functionalization and the more recent ruthenium(II)‐catalyzed asymmetric CH activation reactions are discussed. The structure and properties of the ligands or the ruthenium‐catalysts, which play a decisive role in the control of stereoselectivity, are classified and discussed in each type of reactions.
Asymmetric CH Functionalization of Ferrocene
Authors: Jin Zhong 
Published: October 2022

Abstract
Since the milestone discovery of its sandwich‐type scaffold in the early 1950s, ferrocene and its related organometallic compounds have received enormous interest from chemistry, biology, and material communities. The rigid molecular architecture and aromaticity make them relatively stable and applicable as catalysts or ligands for the diverse organic transformations. To date, a wide range of synthetic methodologies for this unique family of organometallic compounds have been developed, given their widespread application in organic synthesis. Among them, the recent direct CH functionalization catalyzed by transition metals provided an atom‐ and step‐economical approach to the structurally diverse ferrocene derivatives. In particular, transition metal‐catalyzed asymmetric CH functionalization of ferrocene has proven an efficient, enantioselective strategy for the synthesis of planar‐chiral ferrocenes. In this article, the recent progress on direct asymmetric CH functionalization of ferrocene derivatives is summarized.
Synthesis of Heteroatom Stereocenters by Enantioselective CH Functionalization
Authors: Cao Zhen , Tang Wenjun 
Published: October 2022

Abstract
Enantioselective CH functionalization is one of the most straightforward and efficient approaches to access synthetically valuable chiral molecules. Only recently, transition metal‐catalyzed enantioselective CH functionalization has been explored to construct heteroatom stereocenters, providing molecules with heteroatom stereocenters that cannot be accessed otherwise. This article aims to provide a recent update toward the construction of heteroatom stereocenters through enantioselective CH functionalization including desymmetrization approach and resolution approach. The content is categorized according to the formed stereogenic atoms including P, Si, S‐stereocenters.
Iron‐Catalyzed Benzylic CH Functionalization
Authors: Zhou Lulu , Gao Yanqun , Huang Qiping , Wu Hao , Han Wei 
Published: October 2022

Abstract
Among diverse CH bonds, direct functionalization of the benzylic position is particularly fascinating but a challenging process for synthetic chemists because alkyl arenes are abundant, cheap, and stable and at the same time suffer from issues of selectivity, functional group compatibility, and inclination toward over oxidation in benzylic CH functionalization. Among various transition metals, iron ideally conforms to the spirit of element strategy initiative. Hence, iron‐catalyzed benzylic CH functionalization has emerged as an area of significant interest to researchers. We will endeavor to highlight the recent advances in iron‐catalyzed benzylic CH functionalization for constructing CC, CN, and CO bonds. We hope that this review will be useful for synthetic organic chemists and inspire further discoveries in the interesting iron‐catalyzed CH functionalization area.
Ruthenium‐Catalyzed Benzylic CH Functionalization
Authors: Sreedharan Ramdas , Muthuvel Karthick , Gandhi Thirumanavelan 
Published: October 2022

Abstract

The activation and functionalization of the benzylic CH bond by transition metal catalysts have gathered much attraction owing to their occurrence in agrochemicals, pharmaceuticals, and fine chemicals. Among the various active metal catalysts, ruthenium gained upper hand, as they are comparatively economic as well as show versatile catalytic activity. Ruthenium efficiently activates the benzylic C(sp
3
)H bond and effects alkylation, arylation, allylation, vinylation, cyanation, silylation, amination, amidation, and oxidation reactions.
Pd‐Catalyzed Benzylic CH Functionalization
Authors: Thorat Raviraj A. , Jain Saket , Parganiha Devendra , Kumar Sangit 
Published: October 2022

Abstract
Palladium‐catalyzed benzylic CH functionalization has enormous application in industry and academia. Conventional methods have limited scope and selectivity toward functionalization attributed to the very high reactivity of benzylic position particularly benzylic anion. This article discusses the current development of palladium‐catalyzed benzylic CH functionalization involving CC, CO, CN, and CF bond formation which not only tame the reactivity of benzylic anion but also enables its reaction with a large variety of substrates. Some of the applications such as construction of biologically, pharmaceutically, and agrochemical relevant organic molecules have been discussed. This article summarizes palladium‐catalyzed benzylic CH functionalization in a comprehensive way.
Selective Functionalization of BH Bond of
o
‐Carboranes
Authors: Cao Ke , Zhang Cai‐Yan , Wu Ji , Yang Junxiao 
Published: October 2022

Abstract

Icosahedral carboranes are a class of carbon–boron molecular clusters with three‐dimensional aromaticity, which have growing applications in functional materials, boron neutron capture therapy agents, organometallic, and coordination chemistry. To further expand the application of
o
‐carboranes, the functionalization of
o
‐carboranes with diverse groups and controllable regioselectivity has been a challenging subject as the 10 BH bonds are not fully equal and have a slight difference in reactivity. In the past six years, transition metal‐catalyzed BH activation has been proved to be a powerful tool to accomplish the regioselective functionalization of
o
‐carboranes and achieved much advancement in this field. This article summarizes recent advances around BH activation.
Photocatalytic Continuous‐Flow Methods for CH Functionalization
Authors: Pieber Bartholomäus 
Published: October 2022

Abstract
Photocatalysis provides many strategies for the direct functionalization of CH bonds through various mechanisms. All of these reactions require efficient irradiation of the reaction mixture, which limits the use of traditional batch techniques. Continuous flow chemistry, on the contrary, is ideally suited for such transformations due to the small reactor dimensions, which ensure efficient irradiation of the entire reaction mixture. This leads to reduced reaction times, higher selectivities, and provides a straightforward opportunity to scale such transformations to synthetically useful quantities. The enabling technology also offers precise control of the reaction time and temperature to ensure high reproducibility. Moreover, flow setups enable the straightforward and efficient use of gaseous reagents due to the high interfacial area of biphasic reaction mixtures in flow reactors. The stoichiometry of gases can be precisely controlled using mass flow controllers and their solubility in the liquid phase can be increased using higher system pressures, thereby accessing reactions that are otherwise difficult or impossible to realize. This article summarizes and discusses the applications of flow chemistry for photocatalytic CH functionalization.
Direct Functionalization of Unactivated C(sp
3
)H Bonds via Photocatalyzed Hydrogen Atom Transfer
Authors: Gong Lei , Lin Yu‐Mei 
Published: October 2022

Abstract

The direct and selective functionalization of unactivated C(sp
3
)H bonds is one of the most attractive goals in synthetic chemistry. While the radical‐mediated hydrogen atom transfer (HAT) process has shown considerable potential in such reactions, it faces fundamental problems associated with reactivity and selectivity. This chapter describes the strategies of indirect HAT (
i
‐HAT) and direct HAT (
d
‐HAT) photocatalysis developed for C(sp
3
)H functionalization in unactivated aliphatic hydrocarbons and remote C(sp
3
)H feedstocks. A number of examples demonstrate the advantages of HAT photocatalysis for the initiation of radical processes in a mild and controllable manner, which can help to achieve useful chemo‐, site‐, and stereoselectivity. Combination of such reactions with asymmetric catalysis, offering appealing opportunities to furnish chiral products from the most abundant starting materials, is discussed. Such advances in this methodology will stimulate further progress in diversity‐oriented synthesis, catalysis, pharmaceutics, and material science.
Mechanistic Insights into Nickel‐Catalyzed CH Functionalization Reactions
Authors: Shu Xing‐Zhong , Pang Xiaobo , Wei Xiao‐Xue 
Published: October 2022

Abstract
In this article, we summarize the four mechanisms according to the experimental and theoretical basis in chronological order. These include the oxidative addition process, base‐assisted nickelation of CH bonds, the ligand‐to‐ligand hydrogen transfer (LLHT) process, and σ‐bond metathesis. Meanwhile, the representative efforts in nickel‐catalyzed CH functionalization in the past two decades are also summarized. These reactions typically involve (i) the hydrocarbonation of unsaturated CC bonds; (ii) the coupling reactions of CH with carbon electrophiles and nucleophiles; (iii) the oxidative CH and CH coupling reactions; and (iv) the construction of carbon–hetero bonds.
Transition‐Metal‐Catalyzed Stereo‐ and Chemo‐Selective Alkenyl CH Functionalizations
Authors: Zhang Jian , Zhong Guofu 
Published: October 2022

Abstract
Alkenyl CH bond functionalization represents one step‐/atom economic access to alkene derivatives; however, regio‐ and stereoselectivity controlling remains a challenging goal. Although many attentions have been made on the site‐selective aromatic CH functionalizations, there have been much less examples on selective alkenyl CH functionalizations presumably due to the reaction lability and conformation flexibility. Group‐directed CH functionalizations lead to site‐ and stereo‐selective formations of CC and CX bonds. This article focuses on transition‐metal‐catalyzed vicinal‐ and geminal‐group‐directed alkenyl CH functionalizations, such as alkenylation, alkylation, allylation, arylation, halogenation, alkynylation, silylation, and cyanation to be proceeded by the formation of exo‐/endo‐metallocycles.
Innate Directing Group‐Guided Transition Metal‐Catalyzed C(sp
2
)H Activation: Functionalization of Biosignificant Heterocyclic Scaffolds
Authors: Seth Kapileswar 
Published: October 2022

Abstract

The transition metal‐catalyzed CH activation is a fundamentally important organic transformation. The Lewis basic coordinating atoms, which typically function as directing control, have set the stage for efficient transition metal‐catalyzed CH functionalizations in a site‐ and regioselective fashion. Frequently, the directing atom(s) is a preexisting intrinsic part of the molecular entity naturally and remains unperturbed to the skeleton at the end of the desired CH functionalizations. This has been the case with several heterocycles and can be classified as innate directing group (DG). Different types of CC bond formation via innate DG‐assisted CH activation of selected biosignificant heterocyclic scaffolds have been presented; in particular, the functionalizations of C(sp
2
)H bond have been covered.
Gold‐Catalyzed CH Activation/Functionalization Reactions
Authors: Hu Chao , Hashmi A. Stephen K. 
Published: October 2022

Abstract
Gold catalysis has exhibited significant potential in CH activation/functionalization; a broad array of versatile synthetic methods have been developed; and various new reactions have been established. This article discusses a selection of recent seminal advances and conceptual breakthroughs of gold‐catalyzed CH bond functionalization of alkynes, arenes, and alkanes, aiming to provide the reader with an overview of the progress and potential in this rapidly growing research field.
Visible‐Light‐Promoted Fluorine‐Containing Functionalization of C(sp
3
)H Bonds
Authors: Zhao Chuan‐Gang , Wang Chenkun , Li Weipeng , Zhu Chengjian , Xie Jin 
Published: October 2022

Abstract

image

This article provides a general overview of the visible‐light‐mediated conversion of C(sp
3
)H bonds to fluorine‐containing functional groups. We summarized different types of CH fluorine‐containing functionalization reactions, including the reactive C(sp
3
)H bond of carbonyl compounds, relatively weak C(sp
3
)H bonds such as α‐C(sp
3
)H adjacent to heteroatoms and benzylic CH bonds as well as the nonactivated C(sp
3
)H bonds of aliphatic alkanes. A wide range of fluorine‐containing functionalization of C(sp
3
)H bonds are discussed, such as trifluoromethylation, fluoroalkenylation, perfluoralkylation, trifluoromethylthiolation, and fluorination.
Recent Advances in Boron‐Mediated CH Functionalization
Authors: Zhang Zhenguo , Ji Liang , Liu Xiaoxiao , Jia Zhenhua 
Published: October 2022

Abstract
The CH functionalization of organic molecules has become an efficient approach to access diverse bioactive compounds and functional materials. In recent years, transition metal catalysts dominated the field of CH functionalization, such as Rh, Pd, Ir, and Ru. The main group‐centered complexes, especially organoboron reagents, emerged as an alternative option to mediate CH functionalization and received lots of attention in the pharmaceutical and agricultural industries due to their metal‐free feature avoiding to remove metal residues from the final products. In this article, we summarize the recent advances in boron‐mediated CH functionalization, such as CH borylation, CH silylation, CH insertion, CH alkylation, CH hydroxylation, CH deuteration, and other transformations involving CH activation.
Iridium‐Catalyzed C(sp
2
)H Bond Functionalization
Authors: Machado Luana A. , Jardim Guilherme A. M. , Bozzi Ícaro A. O. , Pedrosa Leandro F. , Wood James M. , da Silva Júnior Eufrânio N. 
Published: October 2022

Abstract

Over the last two decades, iridium catalysis has emerged as a reliable tool for the functionalization of C(sp
2
)H bonds, enabling the development of catalytic methods for the construction of complex molecular scaffolds from simple building blocks. The unique reactivity of iridium complexes has enabled breakthroughs in fundamental and applied CH bond activation chemistry, unlocking several types of reactions. Herein, general aspects and key concepts regarding the reactivity of iridium catalysts toward a variety of C(sp
2
)H bonds are discussed. Relevant iridium‐catalyzed CH functionalization methodologies are also highlighted, featuring arene and heterocyclic substrates, as well as more challenging vinylic substrates and examples of distal CH activation reactions.
Heterocycles Synthesis by (Cross)‐Dehydrogenative Coupling
Authors: Mondal Rakesh , Guin Amit K. , Paul Nanda D. 
Published: October 2022

AbstractHeterocyclic compounds are ubiquitous in nature and constitute the backbone of many naturally occurring and synthetic organic compounds having a broad spectrum of biological and pharmacological activities. Due to the importance of this class of compounds, the development of straightforward, efficient, atom‐economical, and eco‐friendly synthesis of various heterocyclic compounds has always drawn considerable attention. Among the different available synthetic methodologies, the cross‐dehydrogenative coupling (CDC) reactions represent one of the most efficient and straightforward approaches, which do not require the time‐consuming multistep prefunctionalization of starting precursors. In this article, we concentrated on various CDC approaches for the synthesis of different heterocyclic compounds. Both transition metal‐catalyzed and ‐free methodologies developed over the past decades have been summarized.
Recent Advances of Unactivated C(sp3)H Functionalization via Radical Pathway
Authors: Zhou Liejin , Zhang Zuxiao 
Published: October 2022

AbstractRadical C(sp3H) functionalization has been experienced a rapid growth with the renaissance of radical chemistry. The newly developed radical generation and radical trap methods enabled numerous regio, chemo, and enantioselective CH functionalization which offered a distinct and complementary strategy for CH functionalization compared with traditional CH activations. In this article, we summarized the recent advances of radical C(sp3)H functionalization reactions which involved the generation of carbon radical from CH bonds. Representative examples were selected to explain the factors affecting the selectivity of HAT. In addition, the methods to trap carbon radicals to install various functional groups are discussed as well.
CH Carboxylation with CO
2
Authors: Hu Xin‐Long , Jiang Yuan‐Xu , Song Lei , Yu Da‐Gang 
Published: October 2022

Abstract

In this article, we outline the development of using CO
2
as the carboxyl source in CH bond functionalization. As the main products of CO
2
‐involving organic synthesis, carboxylic acids and their derivatives are highly important and widely used. Among the numerous methods to generate carboxylic acids, the direct carboxylation of CH bonds with CO
2
is the most efficient in an atom‐economical way. The development of the direct carboxylation of different CH bonds with CO
2
is summarized separately. A summary and outlook of this area are presented.
Transition Metal‐Catalyzed CH Bond Functionalization Involving Metal Migration
Authors: Ju Cheng‐Wei , Zhao Dongbing 
Published: October 2022

Abstract
Transition metal‐catalyzed CH functionalization has become a pivotal organic transformation in the past decades. Numerous methodologies involving transition metal migrations have evolved into novel and significant synthetic tools for the introduction of metallic moiety into positions that have challenged traditional methods. The metal migration process is accompanied by concurrent migration of a hydrogen atom in the direction opposite to that of the metal migration. The current article provides an overview of catalytic CH functionalization involving 1,4‐ and 1,5‐metal‐migration processes with a focus on Pd‐ and Rh‐catalyzed reactions to demonstrate the synthetic power of such strategies.
Copper‐Mediated Free‐Radical C(sp
3
)H Activation
Authors: Kumar Nivesh , Liu Shuai , Robert Frédéric , Landais Yannick 
Published: October 2022

Abstract

The availability, low cost, and toxicity of copper as compared to other transition metals have led to an increasing interest in organic synthesis. This article describes recent advances in the field of Cu‐mediated C(sp
3
)H activation and the formation of new CO, CC, CN, CX, and CS bonds. Here, we describe the role of copper in the generation of hydrogen atom transfer agents and its involvement in the subsequent formation of new bonds from unactivated CH bonds. Many examples are provided which illustrate the versatility of the methodology in the synthesis of ethers, esters, amines, thioethers, and the possibility of late‐stage functionalization of complex molecules starting from simple hydrocarbon precursors. Mechanisms are discussed, which have allowed a rapid development of this operationally simple strategy leading to high‐value substrates.
The Functionalization of Amino Acids, Peptides, and Derivatives by Cross‐Dehydrogenative Coupling
Authors: Phillips Ana M. Faisca , Pombeiro Armando J.L. 
Published: October 2022

Abstract
Modified or unnatural amino acids and peptides are required for a number of applications, which include drug development, diagnostics, to study protein function, for vaccine development, and also for synthetic building blocks and catalysts. By joining two native CH bonds directly, cross‐dehydrogenative coupling provides an efficient, atom‐economical, and environmentally friendly methodology for the α‐functionalization of these substances. Many oxidants, including air, may be utilized to facilitate the loss of hydrogen, and several types of catalysts, metal or organocatalysts and even light, are now known that activate CH bonds for a variety of applications. Site‐selective peptide functionalization is possible in some cases, compatible with the presence of many functional groups in the molecules, and also asymmetric synthesis. This article revises the literature available on this topic, covering at the same time the reaction mechanisms involved and studies performed to elucidate them, aiming to interest the reader in potential future applications.