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The present work reveals a new metal-catalyzed synthetic reaction involving 1,2,3-benzotriazinones with carbonyl sulfoxonium ylide and iodonium ylide, resulting in divergent products. Within this catalytic system, 3-phenylbenzo[d][1,2,3]triazin-4(3H)-one derivatives undergo C–H alkylation processes facilitated by a Cp*Rh(III) catalyst when combined with a carbonyl sulfoxonium ylide. On the other hand, when iodonium ylide substrates are used, they undergo an alkenylation reaction facilitated by a Cp*Ir(III) catalyst. In addition, hydrazone products are produced by synthesizing iodonium ylide substrates with the use of a copper catalyst. These transformations demonstrate mild reaction conditions, a wide range of substrates, and excellent compatibility with various functional groups. The strategy and tactics utilized have been effectively implemented on a significant scale. [ABSTRACT FROM AUTHOR]

Herein, we have demonstrated a palladium‐catalyzed γ‐alkenylation of unactivated alkenes with vinylcyclopropanes. A bidentate 8‐aminoquinoline directing group was utilized for the regioselective γ‐C(alkenyl)−H functionalization of unactivated alkenes with vinylcyclopropanes. This protocol exhibits wide substrate scope and good selectivity. Additionally, substrate diversification was performed to demonstrate the synthetic utility of the protocol. Mechanistic investigations were carried out to provide an insight to the reaction mechanism. A plausible mechanism was also proposed for the present methodology. [ABSTRACT FROM AUTHOR]

Tf2NH‐mediated decarboxylative dearomatization reaction of benzonorcaradiene γ‐ketoacids, in situ generated by intramolecular alkenylation of alkynylcyclopropane γ‐ketoacids or their tert‐butyl esters, has been described for regioselective synthesis of polyfunctionalized 1‐acylmethyl‐4‐arylnaphthalenes. [ABSTRACT FROM AUTHOR]

In this Short Review, we discuss radical reactions using 1,2-bis(phenylsulfonyl)ethylene (BPSE), which has drawn significant attention as a versatile building block for (phenylsulfonyl)ethenylation. Regardless of its E or Z form, BPSE exhibits reliable reactivity towards the attack of alkyl and aryl radicals in order to function as a reliable radical C2 synthon. 1 Introduction 2 Use in Radical Chain Reactions 3 Use in Reactions Utilizing an Electron-Transfer Process 4 Use in Radical-Based C–H Alkenylation 5 Conclusion [ABSTRACT FROM AUTHOR]

Allylic amines are prevalent and vital structural components present in many bioactive compounds and natural products. Additionally, they serve as valuable intermediates and building blocks, with wide‐ranging applications in organic synthesis. However, direct α‐C(sp3)−H alkenylation of feedstock amines, particularly for the preparation of α‐alkenylated cyclic amines, has posed a longstanding challenge. Herein, we present a general, mild, operationally simple, and transition‐metal‐free α‐alkenylation of various readily available amines with alkenylborate esters in excellent E/Z ‐ and diastereoselectivities. This method features good compatibility with water and oxygen, broad substrate scope, and excellent functional group tolerance, thereby enabling the late‐stage modification of various complex molecules. Mechanistic studies suggest that the formation of a photoactive electron donor‐acceptor complex between 2‐iodobenzamide and the tetraalkoxyborate anion, which subsequently undergoes photoinduced single electron transfer and intramolecular 1,5‐hydrogen atom transfer to generate the crucial α‐amino radicals, is the key to success of this chemistry. [ABSTRACT FROM AUTHOR]

In contrast to the locked fluxionality of norcaradienes fused by benzene, unexplored less aromatic heterole‐fused norcaradienes, creatively generated by intramolecular hydroarylation of heteroaryl alkynylcyclopropanes, reserve a balancing fluxionality that permits a dearomative [1,5]‐sigmatropic carbon shift of norcaradienes akin to the reduced aromaticity of heterole. This “walk” shift was confirmed by the isolation of a cycloheptatriene species derived from ring‐expansion of a dearomatized alkynylated heterole‐fused norcaradiene. A following ester‐directed ring‐opening rearomatization of these dearomatized heterole‐fused norcaradienes gives the products featuring migratory acylmethyls that are competent for helicenation with the neighboring (hetero) arenes via (formal) dehydrative alkenylation. Such balancing reactivity of heterole‐fused norcaradienes will open up the opportunity for the development of controllable reactions of fused norcaradienes. [ABSTRACT FROM AUTHOR]

A palladium‐catalyzed highly C−S‐selective Stille cross‐coupling between aryl thianthrenium salts and tri‐ or tetrasubstituted alkenyl stannanes is described. Herein, critical challenges including site‐ and chemoselectivity control are well addressed through C−H thianthrenation and C−S alkenylation, thereby providing an expedient access to stereodefined tri‐ and tetrasubstituted alkenes in a stereoretentive fashion. Indeed, the palladium‐catalyzed Stille‐alkenylation of poly(pseudo)halogenated arenes displays privileged capability to differentiate C−S over C−I, C−Br, C−Cl bonds, as well as oxygen‐based triflates (C−OTf), tosylates (C−OTs), carbamates and sulfamates under mild reaction conditions. Sequential and multiple cross‐couplings via selective C−X functionalization should be widely applicable for increasing functional molecular complexity. Modular installation of stereospecific alkene motifs into pharmaceuticals illustrated the synthetic application of the present protocol in drug discovery. [ABSTRACT FROM AUTHOR]

A carboxylate-directed regioselective Heck-type alkenylation and alkenylative lactonization of (E)-β,γ-unsaturated carboxylic acids by simply substrate control is reported. (E)- and (Z)-alkenyl bromides reacted to give energetically more favorable palladacyles, allowing access to fully stereocontrolled conjugated 1,3-dienes and alkenyled γ-lactones. Mechanistic studies suggest that excellent regioselectivity may be strongly influenced by the steric factors of reactants involved in the palladacycle intermediates. [ABSTRACT FROM AUTHOR]

Chiral tertiary alcohols are an important structural motif, however, the general and efficient methodologies for their synthesis are less reported. Herein, we report a Ni(ІІ)-catalyzed asymmetric alkenylation and arylation of aryl ketones with organoborons under air via a 1,5-metalate shift strategy to obtain chiral tertiary allylic alcohols and diaryl alcohols. The reaction demonstrates good functional group tolerance and delivers chiral tertiary alcohols with good to excellent results. Furthermore, this method can be applied to the late-stage modification of drugs and the efficient synthesis of natural products. Notably, the reaction proceeds through an outer-sphere mechanism. The Ni(II) complex functions both as a Lewis acid to activate the ketone and create a chiral environment, and as coordination bridge linking the ketone and the organoboron-derived "ate" complex, facilitating the 1,5-metalate shift without forming a C-Ni bond. This approach contrasts with traditional transition metal-catalyzed nucleophilic addition reactions that involve carbon-metal bond formation. Chiral tertiary alcohols are an important structural motif, but the general methodologies for the synthesis are less reported. Herein, the authors report a Ni(ІІ)-catalyzed asymmetric alkenylation and arylation of aryl ketones with organoborons under air via a 1,5-metalate shift to obtain chiral tertiary allylic alcohols and diaryl alcohols. [ABSTRACT FROM AUTHOR]

Conversion of quinoline C−H bonds into C−C bonds is essential for obtaining the enormous array of derivatives required for pharmaceutical and agrochemical development. Despite over a century of synthetic efforts, direct alkylation and alkenylation at C3−H positions in a wide array of quinoline precursors remain predominantly challenging and elusive. This report outlines the first successful quinoline C3−H alkylation and alkenylation reactions, exhibiting exceptional regio‐ and stereoselectivity, all achieved under redox‐neutral and transition‐metal‐free conditions. The method involves a three‐step, one‐pot or two‐pot sequence, including 1,4‐dearomative addition, functionalization at C3, and elimination or transalkylation to produce 3‐alkylated/alkenylated quinolines. The presence of a carbonyl group in these products allows for further synthetic manipulations, enabling the production of cyanides, amides, amines, and simple alkyl derivatives. [ABSTRACT FROM AUTHOR]

The mechanism of an iron‐catalyzed C—H alkenylation of pivalophenone derivatives with unsymmetric internal alkynes is investigated in details by means of density functional theory calculations. It is shown that the reaction begins with two consecutive ligand exchanges, followed by a fast and reversible oxidative addition C—H activation step. Next, an alkyne insertion into the Fe—H bond, two isomerization steps, and a reductive elimination afford the final product. The reductive elimination is the turnover‐limiting step of the process, and also determines the regiochemical outcome of the reaction. The origin of the regioselectivity is proposed to be the steric repulsion between the bulky trimethylsilyl group and the aromatic fragment in the reductive elimination step leading to the not observed regioisomer. [ABSTRACT FROM AUTHOR]

Herein, we describe a reaction conditions‐based switchable Rh(III)‐catalyzed C−H alkylation and alkenylation of 1,2,3‐benzotriazinones with maleimides, where the triazinone serves as a directing group rather than its traditional role denitrogenative precursor. This strategy enables the selective synthesis of diverse 3‐arylated succinimides and 3‐arylated maleimides in up to 99% yield and a broad substrate scope (48 examples). Furthermore, for the first time, a tandem C−H alkylation and denitrogenative coupling of 1,2,3‐benzotriazinones has been achieved by slightly modifying the reaction conditions. Additionally, gram‐scale reactions and product derivatizations were conducted to demonstrate the synthetic utility. [ABSTRACT FROM AUTHOR]

Quinazolines are biologically potent heterocyclic compounds; however, their synthesis poses high challenges. In this present study, we have developed an inexpensive cobalt metal‐catalyzed acceptorless dehydrogenative pathway for the sequential synthesis of alkenylated quinazolines from benzhydrol via dehydrogenation, cyclization, and subsequent dehydrogenative sp3 C−H functionalization. This transformation holds potential owing to its commercially available key starting materials, good functional tolerance, moderate reaction conditions, environmental friendliness, and applicability for gram‐scale synthesis. Furthermore, the synthetic utility of the synthesized derivatives has been explored through various reactions, including reduction, halogenation, methoxylation, Michael addition, and spiro cyclization. Additionally, the photophysical properties indicate that the nitrogen atom of the synthesized derivatives readily undergoes a reversible protonation, leading to significant changes in colour. This characteristic presents an opportunity for the creation of pH sensors with colourimetric capabilities. [ABSTRACT FROM AUTHOR]

Regioselective distal C−H functionalization of nitroarenes by overriding proximal C−H activation has remained an unsolved challenge. Herein, we present a palladium-catalyzed meta-C−H alkenylation of nitroarene substrate, achieved through leveraging the non-covalent hydrogen bonding interactions. Urea-based templates comprising an elongated biphenyl linker designed in such a way that it interacts with nitro group via strong hydrogen bonding interaction, while a cyano based directing group is attached along the template to coordinate with the palladium center, thereby facilitating the activation of the remote meta-C−H bond of nitrobenzene. Computational mechanistic investigation and the analysis of non-covalent interaction deciphers the crucial role of H-bonding in regulating the regioselectivity. Regioselective distal C-H functionalization of nitroarenes by overriding proximal C-H activation has remained an unsolved challenge. Herein, the authors present a palladium-catalyzed meta-C-H alkenylation of nitroarene substrate, achieved through leveraging the noncovalent hydrogen bonding interactions. [ABSTRACT FROM AUTHOR]

Catalytic enantioselective alkenylation of aldehydes with easily accessible alkenyl halides promoted by a chiral cobalt complex derived from a newly developed tridentate bisoxazolinephosphine is presented. Such processes represent an unprecedented reaction pathway for cobalt catalysis and a general approach that enable rapid construction of highly diversified enantioenriched allylic alcohols containing a 1,1‐, 1,2‐disubstituted and trisubstituted alkene as well as axial stereogenicity in up to 99 % yield and 99 : 1 er without the need of preformation of alkenyl–metal reagents. DFT calculations revealed the origin of enantioselectivity. [ABSTRACT FROM AUTHOR]

Direct structural modification of small‐molecule fluorophores represents a straightforward and appealing strategy for accessing new fluorescent dyes with desired functionalities. We report herein a general and efficient visible‐light‐mediated method for the direct C−H functionalization of BODIPY, an important fluorescent chromophore, using readily accessible and bench‐stable aryl and alkenylthianthrenium salts. This practical approach operates at room temperature with extraordinary site‐selectivity, providing a step‐economical means to construct various valuable aryl‐ and alkenyl‐substituted BODIPY dyes. Remarkably, this protocol encompasses a broad substrate scope and excellent functional‐group tolerance, and allows for the modular synthesis of sophisticated symmetrical and asymmetrical disubstituted BODIPYs by simply employing different combinations of thianthrenium salts. Moreover, the late‐stage BODIPY modification of complex drug molecules further highlights the potential of this novel methodology in the synthesis of fluorophore‐drug conjugates. [ABSTRACT FROM AUTHOR]

A series of adamantyl-containing alkenes were synthesized by the alkenylation of adamantan-1-ol with secondary alcohols in the presence of sulfuric acid. The scope of application of this reaction was explored to show that the alkenylation reaction with symmetrical dialkylcarbinols occurs in a selective fashion. The alkenylation of adamantan-1-ol with sec-pentanol and its higher homologs gives a mixture of isomeric alkenes. The reactions of substituted adamantanols with isopropanol, butan-2-ol, and cyclohexanol in the presence of sulfuric acid were studied, and a series of new unsaturated derivatives of the adamantane series were obtained. [ABSTRACT FROM AUTHOR]

A direct α‐alkenylation of nitrile compounds was realized with a palladium complex. This method exhibited excellent tolerance toward a variety of α‐aryl alkyl nitriles and vinyl bromides, leading to the formation of a series of α‐quaternary nitriles containing vinyl groups. Further manipulations of the obtained products were demonstrated, highlighting the potential synthetic utility of this method. [ABSTRACT FROM AUTHOR]

Recently, transition metal‐catalyzed ortho‐C−H bond activation/annulations involving two internal alkyne molecules have been extensively used to synthesize highly substituted polycyclic aromatic scaffolds. Such reactions have emerged as a powerful atom and step‐economical strategy for the assembly of multifunctional bioactive molecules. In this context, we focused on the recent achievements of dual C−H bond activation/annulations, as well as functionalization reactions involving diaryl/alkyl alkynes. [ABSTRACT FROM AUTHOR]

A novel alkenylation reaction between N‐hydroxyphthalimide (NHPI) esters and alkenyl sulfones is reported. It undergoes the formation of electron donor‐acceptor (EDA) complex and a series of alkenes are obtained in good to excellent yields. It has the advantages of simple operation, mild reaction conditions, and metal‐free. [ABSTRACT FROM AUTHOR]

Presented herein is the synthesis of diversely functionalized pyrrolizines from the reaction of N-alkoxycarbamoyl pyrroles with CF3-ynones. The formation of the product is based on a C–H bond activation-initiated cascade process including N-alkoxycarbamoyl group-directed alkenylation of the pyrrole scaffold followed by simultaneous intramolecular nucleophilic addition along with cleavage and transfer of the directing group. By taking advantage of the rich chemistry of the transferred alkoxycarbamoyl moiety, the products could be transformed into a series of structurally and biologically interesting pyrrolizine derivatives. To our knowledge, this is the first example in which the N-alkoxycarbamoyl unit acted as a transferable and transformable directing group for the divergent synthesis of pyrrolizines. [ABSTRACT FROM AUTHOR]

C(sp2)−H functionalization offers an efficient strategy for the synthesis of various elaborated N‐containing heteroarenes. Along these lines, oxazino pyridines that can be readily prepared from pyridines, have been introduced as powerful substrates in radical‐ and ionic‐mediated meta‐C−H functionalization. However, the regioselective meta‐C−H arylation of pyridines remains a great challenge. Herein, a copper‐catalyzed meta‐selective C−H arylation of pyridines and isoquinolines through bench‐stable dearomatized intermediates is reported. Electrophilic aryl‐Cu(III) species, generated from readily accessible aryl I(III) reagents, enable the efficient meta‐arylation of a broad range of pyridines and isoquinolines. The method also allows the meta‐selective alkenylation of these heteroarenes using the corresponding alkenyl I(III)‐reagents. Late‐stage arylation of drug‐derived pyridines and larger‐scale experiments demonstrate the potential of this synthetic methodology. [ABSTRACT FROM AUTHOR]

Two N‐heterocyclic olefin‐phosphines (NHOP), and the corresponding ruthenium complexes were synthesized and structurally characterized. One of the cationic complexes [(BzIM)(NHOP)Ru(p‐cymene)Cl2]I was employed as a catalyst in N‐benzylbenzamides/alkyne coupling reactions. With this catalytic protocol a variety of substituted isoquinolones were synthesized through ortho‐selective double C−H bond functionalization involving oxidative annulation followed by olefination reactions. All these products were achieved in one‐pot manner without the use of additives. [ABSTRACT FROM AUTHOR]

A Cu‐catalyzed vinylation method for alkenyl ethers has been developed. In this strategy, both chain and cyclic alkenyl ether substrates were applicable, and the target products were obtained in up to 95% yields and with the E/Z selectivities of >98:2. Furthermore, we have successfully applied this method to directly vinylate the C‐2 position of protected glucals, offering a valuable tool for their functionalization. Moreover, through the utilization of alkenyl alcohols as substrates, we accomplished a 1,2‐alkenyloxylation of alkenyl double bond, enabling the synthesis of functionalized cyclic ether compounds with five or six‐membered rings. [ABSTRACT FROM AUTHOR]

A novel Catellani-type conversion is reported using aryl-thianthreniums (aryl-TTs) instead of aryl halides. Three classes of ortho-dual C–H functionalization involving alkylation, amination, and deuterated methylation and five types of ipso-operation including alkenylation, cyanation, methylation, hydrogenation, and alkynylation all proceed well in this procedure. In this conversion, aryl-TTs exhibit satisfactory reactivity and feature the advantage that the leaving TT unit can be recovered. More strikingly, this finding represents a new chemistry conversion of aryl-TTs, wherein contiguous tri-functionalization in a single chemical manipulation is realized. [ABSTRACT FROM AUTHOR]

Dearomative partial reduction is an extraordinary approach for transforming benzenoid arenes and has been well‐known for many decades, as exemplified by the dehydrogenation of Birch reduction and the hydroarylation of Crich addition. Despite its remarkable importance in synthesis, this field has experienced slow progress over the last half‐century. However, a revival has been observed with the recent introduction of electrochemical and photochemical methods. In this Minireview, we summarize the recent advancements in dearomative partial reduction of benzenoid arenes, including dihydrogenation, hydroalkylation, arylation, alkenylation, amination, borylation and others. Further, the intriguing utilization of dearomative partial reduction in the synthesis of natural products is also emphasized. It is anticipated that this Minireview will stimulate further progress in arene dearomative transformations. [ABSTRACT FROM AUTHOR]

Alkenylbenzene skeletons represent one of the most widely occurring structural motifs in pharmaceutical drugs, natural products, and advanced materials. The construction of alkenylbenzenes is promising through the use of a straightforward oxidative alkenylation protocol, particularly from unactivated alkenes. This is significant because unactivated alkenes are inexpensive raw materials that can be obtained in bulk quantities from petrochemical feedstocks and renewable resources. However, controlling the reactivity and regioselectivity of olefination with unbiased olefins remains a significant challenge, necessitating continuous efforts and potentially having a substantial impact on both organic synthesis and the industry. This review aims to provide an overview of the latest advances in regiocontrol strategies for oxidative alkenylation reactions with unactivated alkenes, which can be categorized into three types: 1) ligand‐promoted/accelerated reactions; 2) prefunctionalized olefins‐facilitated reactions; 3) directing group‐induced reactions. [ABSTRACT FROM AUTHOR]

The late-stage fluorescent labeling of structurally complex peptides bears immense potential for molecular imaging. Herein, we report on a manganese(I)-catalyzed peptide C–H alkenylation under exceedingly mild conditions with natural fluorophores as coumarin- and chromone-derivatives. The robustness and efficiency of the manganese(I) catalysis regime was reflected by a broad functional group tolerance and low catalyst loading in a resource- and atom-economical fashion. [ABSTRACT FROM AUTHOR]

The direct alkenylation with simple alkenes stands out as the most ideal yet challenging strategy for obtaining high-valued desaturated alkanes. Here we present a direct asymmetric dehydrogenative α-C(sp3)-H alkenylation of carbonyls based on synergistic photoredox-cobalt-chiral primary amine catalysis under visible light. The ternary catalytic system enables the direct coupling of β-keto-carbonyls and alkenes through a cooperative radical addition-dehydrogenation process involving a chiral α-imino radical and Co(II)-metalloradical intermediate. A catalytic H-transfer process involving nitrobenzene is engaged to quench in situ generated cobalt hydride species, ensuring a chemoselective alkenylation in good yields and high enantioselectivities. The direct alkenylation with simple alkenes stands out as the most ideal yet challenging strategy for obtaining high-valued desaturated alkanes. Herein, the authors present a direct asymmetric dehydrogenative α-C(sp3)-H alkenylation of carbonyls based on synergistic photoredox-cobalt-chiral primary amine catalysis under visible light. [ABSTRACT FROM AUTHOR]

The construction of silicon‐stereogenic silanols via Pd‐catalyzed intermolecular C−H alkenylation with the assistance of a commercially available L‐pyroglutamic acid has been realized for the first time. Employing oxime ether as the directing group, silicon‐stereogenic silanol derivatives could be readily prepared with excellent enantioselectivities, featuring a broad substrate scope and good functional group tolerance. Moreover, parallel kinetic resolution with unsymmetric substrates further highlighted the generality of this protocol. Mechanistic studies indicate that L‐pyroglutamic acid could stabilize the Pd catalyst and provide excellent chiral induction. Preliminary computational studies unveil the origin of the enantioselectivity in the C−H bond activation step. [ABSTRACT FROM AUTHOR]

The Friedel‐Crafts reaction stands as a powerful synthetic tool for C−H functionalization of aromatic feedstocks, which is conventionally realized through electrophilic alkylation and acylation. The burgeoning interests in axially chiral compounds across diverse fields have spurred extensive exploration of this classic transformation for catalytic atroposelective synthesis. Consequently, the past decade has witnessed the rapid expansion of various non‐canonical Friedel‐Crafts reactions, including electrophilic arylation, alkenylation, halogenation, sulfenylation, and amination of aryl C−H bonds, thereby delving into new chemical spaces. A range of catalytic atroposelective synthetic methods have been devised for these significant arene C−H functionalization. This review provides a comprehensive overview of the cutting‐edge catalytic synthesis of atropoisomers through non‐canonical Friedel‐Crafts reactions, categorized into three parts based on the type of bond formation on the aromatics: C(sp2)−C(sp3) bond formations, C(sp2)−C(sp2) bond formations and C(sp2)−heteroatom bond formations. The richness of electrophiles and the modulation of atroposelectivity by diverse chiral organocatalysts, particularly chiral Brønsted acids, are elucidated. We anticipate that the repertoire of asymmetric Friedel‐Crafts reaction will continue to flourish and to be demonstrated in not only scientific researches but also industrial organic synthesis. [ABSTRACT FROM AUTHOR]

Rh(I)‐catalyzed C8‐selective C−H alkenylation and arylation of 1,2,3,4‐tetrahydroquinolines with alkenyl and aryl carboxylic acids under microwave assistance have been realized. Using [Rh(CO)2(acac)] as the catalyst and Piv2O as the acid activator, 1,2,3,4‐tetrahydroquinolines undergo C8‐selective decarbonylative C−H alkenylation with a wide range of alkenyl and aryl carboxylic acids, affording the C8‐alkenylated or arylated 1,2,3,4‐tetrahydroquinolines. This method enables the synthesis of C8‐alkenylated 1,2,3,4‐tetrahydroquinolines that would otherwise be difficult to access by means of conventional C−H alkenylation protocols. Moreover, this catalytic system also works well in C8‐selective decarbonylative C−H arylation of 1,2,3,4‐tetrahydroquinolines with aryl carboxylic acids. The catalytic activity strongly depends on the choice of the N‐directing group, with the readily installable and removable N‐(2‐pyrimidyl) group being optimal. The catalytic pathway is elucidated by mechanistic experiments. [ABSTRACT FROM AUTHOR]

We report the triply selective and sequential diversification of a single Csp3 carbon carrying Cl, Bpin and GeEt3 for the modular and programmable construction of sp3‐rich molecules. Various functionalizations of Csp3−Cl and Csp3−BPin (e.g. alkylation, arylation, homologation, amination, hydroxylation) were tolerated by the Csp3−GeEt3 group. Moreover, the methodological repertoire of alkyl germane functionalization was significantly expanded beyond the hitherto known Giese addition and arylation to alkynylation, alkenylation, cyanation, halogenation, azidation, C−S bond formation as well as the first demonstration of stereo‐selective functionalization of a Csp3‐[Ge] bond. [ABSTRACT FROM AUTHOR]

An enantioselective cobalt‐catalyzed C(sp3)−H alkenylation of thioamides with but‐2‐ynoate ester coupling partners employing thioamide directing groups is presented. The method is operationally simple and requires only mild reaction conditions, while providing alkenylated products as single regioisomers in excellent yields (up to 85 %) and high enantiomeric excess [up to 91 : 9 enantiomeric ratio (er), or up to >99 : 1 er after a single recrystallization]. Diverse downstream derivatizations of the products are demonstrated, delivering a range of enantioenriched constructs. Extensive computational studies using density functional theory provide insight into the detailed reaction mechanism, origin of enantiocontrol, and the unusual regioselectivity of the alkenylation reaction. [ABSTRACT FROM AUTHOR]

Sequential C−H functionalization of molecules containing multiple C−H bonds can efficiently lead to structural diversity. Herein we present the first chelation‐assisted sequential α‐/β‐C−H functionalization of E‐styrenes with simple alkenes and alkynes in excellent regio‐ and stereo‐selectivity. The process involves α C−H functionalization by six‐membered exo‐cyclopalladation to result in tri‐ and tetrasubstituted 1,3‐dienes and β C−H functionalization through seven‐membered endo‐cyclopalladation to produce tetra‐ and pentasubstituted 1,3,5‐trienes in up to 97 % yield with up to >99/1 E/Z selectivity, both enabled by the chelation assistance of pyrazinamide. The protocol is demonstrated to be widely applicable, tolerant to a wide range of functional groups and bioactive fragments, and suitable for gram‐scale synthesis as well as one‐pot and two step preparation of trienes. Mechanistic experiments and density functional theory (DFT) calculations were performed to elucidate the selectivity and reactivity. [ABSTRACT FROM AUTHOR]

Herein, we report the direct intramolecular coupling of primary and secondary alcohols for the selective synthesis of macrocyclic olefins in the presence of Ni‐zeolite catalyst under continuous flow. This reaction proceeds via dehydration of secondary alcohols to alkenes, which subsequently undergo intramolecular dehydrative coupling reaction with a primary alcohol to obtain moderate yields of macrocyclic olefins. This reaction is also effective for the coupling of secondary‐secondary alcohols and alkene‐alcohols to produce diverse macrocyclic olefin products. This unique approach has various advantages including step‐economy, no additives and pre‐functionalization required, inexpensive and reusable catalyst, and exemplification with 23 macrocycles in different ring sizes. The continuous flow macrocyclisation afforded higher productivity and space‐time yield than the batch reaction conditions. [ABSTRACT FROM AUTHOR]

A palladium‐catalyzed cascade cyclization/alkenylation for the assembly of synthetically valuable isoxazolyl vinylsilane derivative has been accomplished. Easily accessible ynone oximes, and available vinylsilane agents were used as the reaction starting materials This protocol features broad substrate scope, good functional group tolerance, and good step‐ and atom‐economy. Remarkably, this approach provides a new approach for the construction of structurally diverse isoxazolyl‐containing vinylsilanes with high molecular complexity, showing a promising application in synthetic and pharmaceutical chemistry. [ABSTRACT FROM AUTHOR]

The conversion of commercially available chiral sulfinamides into pharmaceutically useful chiral sulfoximines via direct SIV-functionalization is synthetically attractive but challenging due to the competitive reaction of N-functionalization. Herein, we disclose a novel strain-release strategy to access stereospecific and chemoselective SIV-arylation and alkenylation of sulfinamides using arynes and strained cyclic alkynes. This method tolerates an unprecedented chemical diversity of functional groups attached to the nitrogen center (N–R). The origin of the high SIV-selectivity is elucidated by density functional theory calculations, suggesting a stepwise mechanism for the aryne substrates and a concerted mechanism for the cyclic alkynes. [ABSTRACT FROM AUTHOR]

The ortho C−H methylation and ipso C−O alkenylation of aryl triflates was regio‐selectively achieved in one pot by palladium/norbornene (NBE) synergistic catalysis. This work provides an efficient method for preparing poly‐substituted aromatics with (deuterated) methyl and alkenyl groups from the readily available phenoxides. [ABSTRACT FROM AUTHOR]

The transition metal‐catalysed C−H bond functionalization has emerged as a powerful tool for accessing numerous organic compounds in greener manner with step and atom economy. Remarkable progress has been made in the metal‐catalysed C−H bond functionalization during the past decades and the trend is continuing as new reactions are being added. In the transition metal‐catalysed C−H bond functionalization, a growing attention has been paid on ruthenium, particularly, the stable ruthenium(II) as it allows several C−H bond functionalization reactions to perform in water with high selectivity. The ruthenium‐catalysed C−H bond functionalization reactions, such as arylation, alkenylation, annulation, cyanation, amination and silylation just to mention some have been well documented in numerous published papers, book chapters and review articles. However, as ruthenium‐catalysed C−H functionalization has been growing rapidly, a comprehensive review is necessary from time to time to highlight the progress made in this ever expanding field. In view of this, the manuscript presents the ruthenium‐catalysed direct C−O, C−N and C‐halogen bond forming reactions involving aromatic C−H bond covering oxygenation, amination, amidation, imidation, nitration and halogenation reported from 2012 to 2022. [ABSTRACT FROM AUTHOR]

Ortho‐directed electrochemical C−H functionalization of aromatics with boron‐based coupling partners has been achieved under ruthenium catalysis through an oxidatively induced reductive elimination mechanism. Our method provides a single set of conditions delivering C−H arylation, alkenylation and methylation, yielding ortho‐functionalized products with good functional group tolerance, including examples of late‐stage functionalization in synthetically useful yields. By harnessing electricity as a 'green' oxidant, this method circumvents the need for stoichiometric quantities of chemical oxidants, enhancing our sustainability metrics. [ABSTRACT FROM AUTHOR]

An emerging class of C−C coupling transformations that furnish drug‐like building blocks involves catalytic hydrocarbonation of alkenes. However, despite notable advances in the field, hydrocarbon addition to gem‐difluoroalkenes without additional electronic activation remains largely unsuccessful. This owes partly to poor reactivity and the propensity of difluoroalkenes to undergo defluorinative side reactions. Here, we report a nickel catalytic system that promotes efficient 1,2‐selective hydroarylation and hydroalkenylation, suppressing defluorination and providing straightforward access to a diverse assortment of prized organofluorides bearing difluoromethyl‐substituted carbon centers. In contrast to radical‐based pathways and reactions triggered by hydrometallation via a nickel‐hydride complex, our experimental and computational studies support a mechanism in which a catalytically active nickel‐bromide species promotes selective carbonickelation with difluoroalkenes followed by alkoxide exchange and hydride transfer, effectively overcoming the difluoroalkene's intrinsic electronic bias. [ABSTRACT FROM AUTHOR]

The incorporation of the vinylene motif into conjugated molecules notably elevates the HOMO level, augmenting both emissive and conductive properties while enhancing responsiveness to external stimuli. This study focuses on the regioselective C−H/C−H coupling of N‐vinylcarbazole with thiophenes, offering an efficient route to N‐vinylene‐incorporated conjugated molecules for the development of organic electronic materials. Traditional palladium‐catalyzed Fujiwara‐Moritani (FM) reactions proved ineffective for C−H alkenylation with N‐vinylcarbazole. In response, we have developed an iron‐catalyzed twofold alkenylation method for conjugated thiophenes with N‐vinylcarbazole, utilizing trimethylaluminum as the base and diethyl oxalate as the oxidant. This reaction occurs regioselectively at the C2−H (or C5−H) bond of the thiophenes and the terminal position of N‐vinylcarbazole. It also successfully produces short thiophene polymers end‐capped with N‐vinylcarbazole, demonstrating the potential for synthesizing polymeric donor materials. The enamine products exhibit blue‐to‐green emission, high fluorescence quantum yield, and visible light responsivity for stereo‐isomerization, indicating promising applications in organic electronics. [ABSTRACT FROM AUTHOR]

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Catalytic activities of Mn(I) complexes derived from expensive MnBr(CO)5 salt have been explored in various dehydrogenative transformations. However, the reactivity and selectivity of inexpensive high spin Mn(II) complexes are uncommon. Herein, we have synthesized four new Mn(II) complexes and explored switchable alkenylation and alkylation of methyl heteroarenes employing a single Mn(II)catalyst. The developed protocol selectively furnishes a series of functionalized E‐heteroarenes and C‐alkylated heteroarenes with good to excellent yields. Various medicinally and synthetically useful compounds are successfully synthesized using our developed protocol. Various controls and kinetics experiments were executed to shed light on the mechaism,which reveals that α‐C−H bond breaking of alcohol is the slowest step. [ABSTRACT FROM AUTHOR]

Indole derivatives are fundamental structural units in many bioactive compounds and molecular materials. The site‐selective C7‐functionalization of these moieties has been proven to be extremely challenging due to the inherent reactivity of the C2‐ and C3‐positions. Herein, we report the first electro‐C7‐alkenylation of indoles. This novel and sustainable methodology provides highly exclusive access to the C7‐position devoid of often toxic and expensive chemical oxidants. Moreover, an array of substrates was successfully alkenylated at the C7‐position, and versatile product diversification was achieved. [ABSTRACT FROM AUTHOR]

Herein, a novel organic transformation involving rhodium-catalyzed divergent dehydroxylation/alkenylation of hydroxyisoindolinone with vinylene carbonate is reported, and a series of architecturally rigid and widely used spirolactams are obtained with excellent functional group tolerance and high selectivity. Remarkably, the promising vinylene carbonate reagent presents a distinct chemical reactivity as a vinyl-oxygen cyclic synthon and first transfers the C–H bond to spiroheterocycle scaffolds. Moreover, another chemoselectivity, direct dehydrogenative coupling with vinylene carbonate, is also presented. This protocol is compatible with green chemistry and only releases H2O and CO2 as byproducts. [ABSTRACT FROM AUTHOR]

Despite remarkable successes in linear and branched vinyl (hetero) arene synthesis, regiodivergent C−H olefination with a single catalytic system has remained underdeveloped. Overcoming this limitation, a Pd/MPAA‐catalyzed regiodivergent C−H olefination of imidazo[1,2a] pyridine carboxamides with unactivated terminal alkenes to generate branched and linear olefinated products depending upon the electronic nature of alkenes is reported herein. Moreover, this protocol can be applied for C−H deuteriation of the corresponding heteroarenes with D2O as deuterium source. Preliminary experimental studies combined with computational investigations (DFT studies) suggest that regiodivergent olefination can be controlled by olefin insertion and β‐hydride elimination steps. [ABSTRACT FROM AUTHOR]