bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rhodium‐Catalyzed Enantioselective CH Functionalization Using Chiral Cp Ligands
Authors: Dethe Dattatraya H. , Beeralingappa Nagabhushana C. , Singha Chirantan 
Published: October 2022

Abstract

Asymmetric CH functionalization is one of the most step‐ and atom‐economical approaches that provide efficient access to synthetically valuable enantiopure compounds. In this context, various novel transition metal‐catalyzed enantioselective CH functionalizations have been explored from the past few years to construct chiral molecules. The design of Cp

x

ligands and their application toward transition metal‐catalyzed CH functionalization reactions in an enantioselective manner is highly privileged. In this article, recent progress in the Cp

x

Rh‐catalyzed directing group‐assisted enantioselective CH functionalization reaction has been discussed.
Ru‐Catalyzed CH Activations with Oxidizing Directing Groups
Authors: Luo Yanshu , Xia Yuanzhi 
Published: October 2022

Abstract
Transition metal‐catalyzed CH bond activation has emerged as a powerful and ideal method for organic synthesis in recent decades. To avoid the use of over‐stoichiometric oxidant, the concept of oxidizing directing group was introduced for different catalytic systems. Recently, such strategy has been widely employed in the ruthenium‐catalyzed reactions, enabling novel CH functionalization under relatively mild conditions. In this article, progress in the recent development of the Ru‐catalyzed CH activations with oxidizing directing groups was summarized according to different types of internal oxidants. Major findings in the research field, mechanistic information from experimental or theoretical studies, and possible role of the internal oxidant were introduced according to literature reports.
Iron‐Catalyzed CH Activation/Functionalization to Form CC Bonds
Authors: Neidig Michael L. , Bhatia Shilpa , DeMuth Joshua C. 
Published: October 2022

Abstract
Iron‐catalyzed CH activation has attracted great interest over the past couple of decades as a promising technique to establish CC bond‐forming functionalities for complex molecule design. The motivation behind this trend can be attributed to the low cost, minimal toxicity, and rich oxidation chemistry afforded by iron. The synthetic utility of iron catalysis for CH activation/functionalization was widely recognized following the development of an iron‐catalyzed CH activation system that facilitated the cross‐coupling of a CH bond with an organometallic reagent under oxidative conditions. Following this seminal approach, iron‐catalyzed CH activation has been widely explored to establish CC bonds across a variety of functionalities. This article underscores the evolution of CC bond‐forming iron‐catalyzed CH activation by providing several examples across a broad range of CH functionalizations including alkylation, alkenylation, alkynylation, allylation, arylation, and annulation that involve CH‐activated organoiron species through the reaction of a substrate CH bond with an iron catalyst. An additional section of this article is dedicated to highlighting the key mechanistic insights into iron‐catalyzed CH functionalization, a field that is largely underdeveloped yet invaluable toward the rational development of the next generation of systems in iron‐catalyzed CH activation/functionalization.
Copper and Iron‐Promoted Decarboxylative CH Functionalization
Authors: Li Lian‐Hua , Liang Yong‐Min 
Published: October 2022

Abstract
The decarboxylative CH functionalization, as the combination of CH bond activation and decarboxylation, represents a great potential and is one of the eye‐catching key methods for organic syntheses. These reactions show good tolerance to many functional groups. Among the recent advances in decarboxylation processes, to some extent, copper‐ and iron‐promoted strategies occupy significant roles.
Copper‐Catalyzed CH Functionalization: CC Bond Construction via Cross Dehydrogenative Coupling (CDC)
Authors: Morja Mayur I. , Chauhan Prakashsingh M. , Chikhalia Kishor H. 
Published: October 2022

AbstractThe direct CH activation path has rationalized the preparation of functionalized molecules by minimizing the number of synthetic steps, and the processes are more atom economic. One such strategy, cross‐dehydrogenative coupling (CDC) reaction is an expedient synthetic protocol for direct CH functionalization including the construction of CC and CX (X = O, S, N, etc.) bonds. In the past years, considerable advancement has been made in the CC bond formation by using different hybrid CH (sp3, sp2, and sp) substrates via the CDC reaction. Particularly, copper‐catalyzed CDC reactions have attracted considerable attention because copper is an abundant, inexpensive, and environmentally benign metal. This article efforts to provide a comprehensive understanding of the development of cross‐dehydrogenative CC coupling via copper catalysis, as well as its mechanism and application in synthetic chemistry.
Copper‐Catalyzed CN Bond Formation by CH Functionalization
Authors: Wang Zhen , Shi Tao , Zhang Honghua 
Published: October 2022

Abstract

Copper‐catalyzed CN bond formation by CH functionalization has gained increasing attention in recent years, but no review systematically and comprehensively summarizes the references in this field. Herein, we summarized the advances in this field covering literatures from 2008 to 2020, and classified this summary into sp
2
CH functionalization and sp
3
CH functionalization. For each example, the reaction conditions, substrate scope, yield, and if possible, the mechanistic scheme are displayed, and sometimes are compared with similar reactions. At last, the development prospect of this domain is definitely expected to be bright.
Copper‐Catalyzed sp
2
CH Bond Functionalization
Authors: Jain Nidhi , Kaur Ramandeep , Sharma Arun 
Published: October 2022

Abstract

The use of sp
2
CH bonds as key functional groups has been realized by transition metal‐mediated CH bond activation and functionalization. In this regard, copper‐catalyzed CH activation has emerged as an environmentally benign and economically attractive approach in modern synthetic organic chemistry. Copper salts serve as versatile catalysts for oxidative coupling reactions and are often proposed to serve as a one‐electron oxidant to promote the single‐electron transfer process. This article discusses the recent advances in the copper‐catalyzed sp
2
CH functionalization achieving CC, CN, CO, CS, and CX bond formation via direct CH activation as well as directing group‐assisted activation strategy. An understanding of the mechanism of these reactions involving organocopper intermediates is crucial to promote the discovery of efficient and highly selective catalytic systems.
Copper‐Catalyzed sp
3
CH Bond Functionalization
Authors: Karjee Pallab , Sarkar Tanumay , Talukdar Kangkan , Shah Tariq A. , Das Bijay K. , Punniyamurthy Tharmalingam 
Published: October 2022

Abstract

Transition metal‐catalyzed CH functionalization provides an appealing strategy for the transformation of simple substrates into complex molecules with structural diversity. Despite the indispensable advances of CH functionalization developed to date, most of the methodologies demanded the use of expensive 4d and 5d transition metals. On the other hand, because of the low toxicity, less expensive, and one of the most abundant 3d row metals, copper progressively possesses a promising metal for the development of CH functionalization. Herein, we present the diverse array of copper‐based expedient C(sp
3
)H functionalization for the construction of directed and nondirected CC, CN, CO, CS, and Chalogen bonds.
Copper‐Catalyzed CH Functionalization Intermediates and Mechanisms
Authors: Hoover Jessica M. 
Published: October 2022

AbstractCH functionalization reactions enable the efficient introduction of functionality in place of ubiquitous CH bonds. In particular, copper catalysts have seen rapid development and synthetic applications in recent years due, in part, to their ability to easily access multiple oxidation states and intermediates in varied mechanistic pathways. In this article, the predominant mechanistic intermediates and manifolds for Cu‐catalyzed CH activation reactions are presented.
Copper‐Catalyzed CC Bond Formation via CH Functionalization of N‐Heterocycles
Authors: Hore Soumyadip , Singh Abhijeet , Singh Ravi P. 
Published: October 2022

Abstract

The transition metal‐catalyzed CH bond functionalization has been achieved by various catalytic processes, among which copper‐catalyzed reactions have emerged as an environmentally benign and economical alternative. Here, an attempt has been made to collate all the seminal reactions based on CH functionalization to construct CC bond since 2012. This article discusses the evolution of this field from its nascent stages, where strategies for simple activation of sp, sp
2
, and sp
3
CH bonds of pronucleophiles were explored, to the more recent site‐selective reactions. In past decades, many bidentate ligands, for example amino acids, diamines, fused pyridines, oxazolidinones, and amides have transformed the Cu‐catalyzed coupling reactions into a practical and versatile synthetic tool. While the examples have been described with details about reaction conditions, some insight into the mechanistic pathways has also been presented.
Nickel‐Catalyzed Remote CH Bond Functionalization
Authors: Pradhan Suman , Chatterjee Indranil 
Published: October 2022

AbstractThe CH bond is one of the important structural units found in organic compounds. The functionalization of this ubiquitous CH bond has a significant meaning in the field of organic transformation in order to attain several biologically active drug molecules and complex molecular frameworks. Among these activation processes, distant and selective activation of the unactivated CH bond possesses significant challenges as well as rewards. Taking advantage of a functional group present in the molecule, functionalization at the remote position can be achieved. Transition‐metal catalysis is widely applied to perform such remote activation. However, nickel, a first‐row transition metal, shows its great applicability toward this kind of transformation. In this article, the concept of remote bond functionalization is discussed along with various nickel‐catalyzed seminal reports.
Oxidizing and Transformable Directing Groups in CH Functionalization
Authors: Ren Jie , Cui Xiuling 
Published: October 2022

Abstract
Transition metal‐catalyzed direct CH activation has been developed as a powerful strategy for the rapid construction of molecular complexity. The ubiquity and strength of CH bonds present major challenges toward the realization of CH transformations: selectivity and efficiency. The directing groups (DGs) resolved the regioselectivity and improved the catalytic activity of metal. However, they always left a chemical trace in the products, which limited the structural diversity. Hence, the development of multifunctional DGs in CH transformations comprised a central issue recently. This article focuses on the recent progress on the multifunctional DGs in transition metal‐catalyzed CH transformations, including oxidizing, migratable, and transformable DGs, which realize a highly atom‐economical process, incorporate the DGs in the final products, and enrich structural diversity of the products. We expect that these strategies will stimulate further innovative studies thought modifying DGs and developing a novel function of DGs, resulting in the discovery of efficient methods for the synthesis of complex molecules.
C(sp
2
)H Functionalization Guided by Intrinsic Functional Groups
Authors: de Carvalho Renato L. , de Oliveira Joyce C. , da Cruz Kimberly C. T. , Wood James M. , da Silva Júnior Eufrânio N. 
Published: October 2022

Abstract

CH activation has proven to be one of the most versatile synthetic strategies developed so far for the functionalization of sp
2
centers, due to the large variety of reaction conditions available to the practitioner including choice of catalyst, oxidant, additives and also directing group. Regarding the latter, one possibility is to use an intrinsic directing group. These are functional groups resident in the substrate containing a pair of nonbonding electrons, which can interact with the metal center of a catalyst and therefore control the site of CH activation. The use of a directing group that is intrinsic to the molecule is advantageous, as additional synthetic steps are not required for its installation and removal. The implementation of this directing group strategy is therefore guided by the structure of the desired compound and the coordinating ability of heteroatoms within it.
Transition Metal‐Catalyzed CH Bond Activation/Functionalization of Phosphines
Authors: Dixneuf Pierre H. , Soulé Jean‐François 
Published: October 2022

Abstract
Trivalent‐phosphorus‐containing molecules, especially phosphines, are currently used as a ligand in transition metal catalysis. Historically, it was thought that phosphine CH bonds were almost not reactive, but recent examples have demonstrated that it is possible to functionalize them easily under proper conditions. These methods use various Pd, Ir, Ru, and Rh transition metals and native P(III)‐atom as directing groups allowing the regioselective late‐stage functionalization of phosphine ligands. Interestingly, some modified phosphines have outperformed their parent ones in transition metal cross‐coupling reactions. This article summarized the different approaches for the P(III)‐directed CH bond functionalizations.
Heterogeneous CH Functionalization Approaches with Palladium Catalysts
Authors: Mandal Tanmoy , Bhandari Anirban , Choudhury Joyanta 
Published: October 2022

Abstract
Over the last few decades, considerable development in the field of homogeneous transition metal‐catalyzed CH functionalization has been achieved. Nonrecyclable homogeneous catalyst continues to be a major limitation in the field. Heterogenization of homogeneous catalysts allows reusability, making the systems economically and ecologically sustainable. The development of suitable Pd‐based heterogeneous catalysts is an active area of research motivated by the success of the Pd‐based homogeneous catalyst. This article summarizes the Pd‐based heterogeneous platforms for CH functionalization. The article has been divided into two broad sections: (i) Pd‐complex‐based heterogeneous catalysts and (ii) Pd nanoparticles‐based heterogeneous catalysts. Both sections are further divided into sub‐sections based on the supporting platforms used for anchoring the metal. In each section, the efficiency, site selectivity, and reusability of the Pd‐based catalysts are summarized.
Earth Abundant 3d Transition Metals (Fe, Co, Ni) for Nondirected CH Borylation
Authors: Kamitani Masahiro 
Published: October 2022

Abstract
Organoboron reagents are important synthetic intermediates that are often used in the Suzuki–Miyaura cross‐coupling reaction. Versatile and efficient chemical reactions that are capable of introducing a boryl group to an arbitrary organic molecule on demand are essential for the synthesis of new organoboron reagents. The nondirected CH borylation process generates organoboron reagents from a variety of organic molecules via CH‐to‐CB bond transformations. Further, it is widely used in numerous organic syntheses that are followed by coupling reactions, even though it is less selective than directed CH borylations of specific molecules equipped with a directing group. While nondirected borylations were initially catalyzed by precious metals, methods employing catalysts containing earth‐abundant metals (e.g. Fe, Ni, and Co) have been rapidly emerging over the past decade. This article provides a review of recent literature (from 2010 to early 2021) on earth‐abundant Fe, Ni, and Co catalysts for catalytic CH borylation.
Lanthanum‐ and Cerium‐Mediated CH Activation: Spectroscopy, Structures, and Formation of Metal‐Containing Intermediates
Authors: Cao Wenjin , Yang Dong‐Sheng 
Published: October 2022

Abstract
This article examines vibronic spectra, isomeric structures, and formation of transient metal complexes produced in La‐ and Ce‐mediated CH activation reactions of hydrocarbon compounds in the gas phase. The hydrocarbon compounds include small alkenes, alkynes, and alkadienes. Molecular masses of metal complexes are measured with time‐of‐flight mass spectrometry, vibronic spectra are probed with mass‐analyzed threshold ionization (MATI) spectroscopy, and isomeric structures are determined by comparing experimental and computational vibronic spectra, and plausible reaction pathways for the formation of specific isomers are investigated by quantum chemical calculations.
Metal‐Free Radical CH Functionalization via Aldehyde Auto‐Oxidation
Authors: Paul Subhasis , Biswas Promita , Guin Joyram 
Published: October 2022

Abstract

Oxidative functionalization of CH bond involving free‐radical intermediate offers a great opportunity for selective conversion of abundant chemicals to value‐added materials under mild conditions with remarkably high functional group tolerance. Accordingly, radical‐mediated synthesis receives considerable interest in pharmaceutical, agrochemicals, and polymer sciences. Numerous effective strategies for the functionalization of CH bonds through free‐radical intermediate have been developed. Despite these advancements in radical CH functionalization chemistry, the generation of free‐radical intermediate via oxidative homolytic activation of unactivated CH bond under sustainable conditions remains challenging. In this connection, the auto‐oxidation of organic compounds that enables selective generation of reactive free‐radical intermediate upon exposure of organic compounds to O
2
is of particular attraction. The auto‐oxidation of organic feedstocks has already been applied in the industrial production of commodity chemicals such as phenols and terephthalic acid. Nevertheless, the utilization of aerobic oxidation of chemical feedstocks in organic synthesis under reagent‐free conditions is very rare, particularly for small‐scale synthesis of functionalized molecules. Recently, a significant advancement in aerobic radical functionalization of CH bond using aldehyde auto‐oxidation has been achieved. This article provides an overview of the current development on selective functionalization of CH bond using aldehyde auto‐oxidation that proceeds via a radical pathway under reagent‐free conditions.
Platinum‐Catalyzed CX (X = O, B, Cl, Si) Bond Formation Through CH Functionalization
Authors: Huo Shouquan , Li Yumin 
Published: October 2022

Abstract
Low temperature and selective oxidation of unactivated alkanes through CH activation such as direct methane oxidation is a great challenge in chemical transformations, especially in the industry scale, and platinum has played a major role in the field. This article outlines significant achievements in the platinum‐catalyzed methane oxidation including the Shilov reaction and the Periana‐Catalytica system which provide one of the most promising approaches to the challenge. In addition to methane oxidation, some synthetically useful reactions have been developed under improved Shilov conditions, notably the terminal or regioselective CH oxidation of alkyl groups in various substrates. Platinum‐catalyzed CH borylation and silylation reactions are also discussed. Platinum‐catalyzed borylation of CH bonds of sterically congested arenes and fluorinated arenes is particularly noteworthy and it also complements the iridium chemistry in terms of chemo and regioselectivity.
Gold‐Catalyzed C(sp
2
)H Functionalization under Au(I)/Au(III) Catalysis
Authors: Urvashi XXXXXXXX , Singh Pallavi , Patil Nitin T. 
Published: October 2022

Abstract

Among the newer approaches to transition metal‐catalyzed CH functionalization, Au(I)/Au(III) catalysis has emerged as a powerful synthetic tool for the construction of carbon–carbon and carbon–heteroatom bonds. The orthogonal reactivity pattern of gold catalysts as compared to other transition metal catalysts provides an excellent opportunity for the development of new modes of CH functionalization. The rapid enhancement in the field of gold‐catalyzed CH functionalization is complemented by the development of several strategies for achieving the typically arduous Au(I)/Au(III) redox cycle. This article documents all the examples of C(sp
2
)H functionalization under Au(I)/Au(III) catalysis reported so far.
Catalytic Enantioselective CH Borylation
Authors: Xu Liang , Song Peidong , Li Pengfei 
Published: October 2022

Abstract
Organoboron compounds have proven to be versatile building blocks in the synthesis of natural products, organic materials, or drugs. The stereospecific transformations of optically active organoboron compounds, which represent an interesting class of enzyme inhibitors and have been used as marketed drugs themselves, potentially afford chiral products that are in growing demand for the screening of pharmaceutically active candidates. This amplifies the necessity to develop efficient and practical strategies to deliver enantioenriched organoboron compounds. Encouraged by this surging demand, an increasing number of racemic direct CH borylation reactions, which have been developed as a step and atom‐economic approach to borylated products, have evolved into their asymmetric versions based on elegantly designed chiral ligand and catalytic strategies. Herein, a brief summary of these breakthroughs is presented, especially emphasizing their connections with the racemic prototypical transformations. We expect that such introduction will inspire more efficient strategies in this field, enabling a more convenient access of chiral organoboron compounds.
Synthesis of Fused Heterocycles via Transition Metal‐Catalyzed CH Functionalization
Authors: Usuki Yoshinosuke , Satoh Tetsuya 
Published: October 2022

Abstract
This article focuses on synthesis of nitrogen‐containing or oxygen‐containing fused heterocyclic natural products through transition metal‐catalyzed CH functionalization. With highlighting some recent achievements in this field, a current state analysis on this synthetic methodology will be contributed.
CH Activation of Indoles
Authors: Kowalczyk Rafał , Mittal Lalit S. 
Published: October 2022

Abstract
Tremendous advances in transition metal‐catalyzed CH functionalization of the indole scaffolds have been recently reported. Great efforts have been devoted to the directing group strategy development in selectivity achievement overriding both the inherent reactivity of the indole scaffold and the activation of C2/C3H bonds. This article aims to highlight the elegant methods enabling the direct arylation, alkenylation, alkylation, and alkynylation along with the introduction of heteroatoms into indole scaffold via selective metal‐catalyzed CH activation strategies.
Transition Metal‐Catalyzed Site‐Selective CH Bond Arylation of Arenes/Heteroarenes Using Quinone Diazides
Authors: Bera Satabdi , Samanta Rajarshi 
Published: October 2022

Abstract
Transition metal‐catalyzed direct introduction of phenol/naphthol moieties into the arene/heteroarene CH bonds has been studied using quinone diazides. Generally, the reactions proceed via CH insertions of metal carbenes or migratory insertion of metal carbenes. These arylation reactions are further discussed and extended with selected scope, limitations, and plausible mechanism. Interesting enantioselective reactions to provide stereogenic centers and axial chirality are also described. In this article, the summarized progress in the field of site‐selective arylations into CH bonds of arenes/heteroarenes using quinone diazide class of compounds under transition metal catalysis has been described.