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The construction of C(sp³)-P bonds is of paramount importance in organic synthesis, catalysis, and materials science. Organophosphorus compounds containing C(sp³)-P bonds serve as pivotal structural motifs in ligands, pharmaceuticals, agrochemicals, and functional materials. While traditional methods for C(sp³)-P bond formation largely rely on nucleophilic substitution or coupling of reactive organometallic reagents, recent years have witnessed significant advancements in metal-catalyzed approaches. This review highlights the recent developments in C(sp³)-P bond formation enabled by metals including Cu, Fe, Bi, Pd, Ni, Ru, Rh, and Co, with particular emphasis on methodologies that activate simple C(sp³)-H bonds or utilize readily available chemical feedstocks. Key mechanistic paradigms, including photoredox/transition metal dual catalysis, metal-catalyzed radical processes, and photo-induced ligand-to-metal charge transfer (LMCT), are critically discussed. This review evaluates the mechanistic insights, applications, and limitations of these methodologies in the synthesis of organophosphorus compounds, and provides perspectives on future directions to promote further advancements in C(sp³)-P bond formation strategies. [Display omitted] [ABSTRACT FROM AUTHOR]

An efficient, scalable synthetic method of chromeno[3,4- c ]pyridine scaffolds through redox-neutral [4 + 2] annulation between coumarinyl ketoxime esters and internal alkynes has been developed using the rhodium(III) catalytic system. The present transformation proceeds under mild conditions, features good functional group compatibility and obivates the use of external oxidants. Ready access to pyridine derivatives bearing three carbon substituents is exemplified. Image 1 • Efficient & scalable synthesis of chromenopyridines. • Redox-neutral annulation. • Oxime acetates as internal oxidant. • Diversified derivatization. • Easy late-stage functionalization. [ABSTRACT FROM AUTHOR]

An account of our previously disclosed total synthesis of the aryltetralin lignan natural product podophyllotoxin, a building block used in the synthesis of the FDA-approved anticancer drug etoposide, is disclosed. A C–H activation disconnection was viewed as being amenable to the preparation of E-ring modified analogs but proved challenging to execute. Various insights into palladium-catalyzed C–H arylation reactions on complex scaffolds are reported ultimately leading to the implementation of this strategy and the synthesis of compounds inaccessible by semisynthetic means. Image 1 [ABSTRACT FROM AUTHOR]

An efficient rhodium-catalyzed direct C-H activation for the synthesis of isoquinolone with 1,4,2-dioxazol-5-ones as oxidizing directing groups have been developed, which featured mild reaction conditions, short reaction time and satisfactory yield. An efficient approach to isoquinolone have been developed, which featured in completing expeditiously under mild conditions with satisfactory yield. Image 1 [ABSTRACT FROM AUTHOR]

Abstract We report a rhodium-catalyzed ortho C(sp 2)-H borylation of 2-phenylpyridines using commercially available N-heterocyclic carbenes (NHCs) as ligand and pinacolatodiboron (B 2 pin 2) as borylating reagent. The reaction could take place at room temperature, tolerating a wide range of functionalities and affording ortho borylated products in moderate to excellent yields. The current method is also applicable to gram-scale reaction with reduced catalyst loading. Graphical abstract Image 3 [ABSTRACT FROM AUTHOR]

Abstract In this paper, we report the assembling of libraries of β -arylated short/medium/long chain-based non- α -amino acid (aminoalkanoic acid) derivatives via the Pd(II)-catalyzed, bidentate directing group 8-aminoquinoline-aided sp3 β -C-H activation/arylation method. Short/medium chain-based unnatural amino acid derivatives containing an aryl group at the β -position are promising small molecules with therapeutic properties. Thus, it is necessary to enrich the libraries of short/medium/long chain-based unnatural amino acid derivatives containing an aryl group at the β -position. Considering the importance of β -arylated short/medium/long chain-based non- α -amino acid derivatives, an inclusive attention was paid to explore the Pd(II)-catalyzed sp3 β -C-H arylation of short/medium/long chain-based non- α -amino acids. Representative synthetic transformations including a short route for the assembling of rolipram and related compounds and 3-arylated GABA derivatives such as, baclofen, phenibut and tolibut were shown using selected β -C-H arylated non-α-amino acid derivatives. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Abstract A one-pot, multicomponent-type, solvent-free Pd(II)-catalyzed direct β -C-H activation/arylation of carboxamides involving anhydrides as substrates via in situ installation of directing group (DG) is reported. Typically, the DG-assisted β -C-H activation/arylation of carboxamides is a two-step process comprising the installation of DG and Pd(II)-catalyzed C H arylation. We attempted a multicomponent-type reaction comprising an anhydride, a DG (e.g. 8-aminoquinoline), an aryl iodide in the presence of the Pd(II) catalyst and an appropriate additive. Different anhydrides, DGs, aryl iodides, catalysts and additives were screened to reveal the scope of this multicomponent-type C H arylation reaction process and various β -C-H arylated carboxamides were obtained in satisfactory to good yields. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Isocoumarin has been recognised as one of the most privileged heterocyclic motifs for the development of numerous natural product-inspired biologically important compounds. Due to the diverse biological activities of isocoumarins and their role as a pivotal intermediate in synthetic organic chemistry, continuous efforts are devoted towards its synthesis via either traditional or metal-catalyzed reactions. The metal complexes of palladium, copper, rhodium, ruthenium, iridium, nickel, zinc and silver are being frequently utilized for the construction of the isocoumarin scaffolds. Among the traditional methods, electrophilic cyclizations, halo-lactonizations are well known methodologies for the development of isocoumarins. This systematically and critically analysed review highlights recent developments in the synthesis of isocoumarin derivatives with plausible reaction mechanisms, their natural occurrence and pharmacological importance, together with their potential applications in medicinal chemistry as active pharmaceutical agents. In this review, the recent developments in synthesis of biologically important isocoumarin derivatives with plausible reaction mechanisms, their natural occurrence and pharmaceutical importance along with their applications in various fields have been discussed. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract A simple and efficient Rh(III)-catalyzed C-H activation and tandem intramolecular cyclization for the synthesis of isocoumarins has been developed. The protocol uses easily available primary benzamides and cyclic 2-diazo-1,3-diketones as starting materials. This reaction proceeds via C-C and C-O bond formation in a single reaction vessel, and the corresponding isocoumarins were obtained in moderate to excellent yields (58%–97%). The well established protocol showed high functional group tolerance, which provided an efficient and alternative route to isocoumarin backbone. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Abstract Vinyl acetate is used as an acetylene equivalent in rhodium(III)-catalysed C-H activation/annulation with aryl ketoxime esters. Extension to an aldoxime ester allows for a concise formal synthesis of decumbenine B. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Hydrogen isotope exchange (HIE) is a versatile method for the introduction of deuterium to organic compounds. Herein, regioselective deuteration of sulfonamides is achieved by palladium-Catalyzed HIE reaction. By using amino acid as weakly coordination-directing auxiliary, a variety of sulfonamides are efficiently deuterated at the ortho -position. Placing competing directing groups on the aromatic ring does not affect the site-selectivity. [ABSTRACT FROM AUTHOR]

The C–H activation of aryl amide using readily available Pd(OAc) 2 in the presence of selectfluor is reported. The highly mono-selective introduction of sp 2 hybridized functional groups have been realized. A broad range of aryl-, alkenyl- and keto-aryl amides were prepared using unactivated coupling partners under mild conditions. [ABSTRACT FROM AUTHOR]

An efficient and straightforward protocol for the synthesis of tetrahydrophenanthridine N -oxides has been achieved from easily available cyclic 2-diazo-1,3-diones with aryloximes. This transformation proceeded through Rh(III)-catalyzed C–H activation and subsequent intramolecular cyclization under mild conditions, and involved the formation of two new bonds (C–C & C–N) in a single reaction vessel for the construction of novel fused isoquinoline N -oxides, with N 2 and H 2 O being generated as the only by-products. Noteworthy, the process could be easily performed in one mmol scale as well as scaled up to gram-scale synthesis without reducing the percentage yield. To create your abstract, type over the instructions in the template box below.Fonts or abstract dimensions should not be changed or altered. [Display omitted] [ABSTRACT FROM AUTHOR]

An intramolecular C(sp 3 ) H bond functionalization adjacent to an amide nitrogen atom was successfully developed for synthesis of 2-hydroxybenzoxazinone derivatives under environment-friendly conditions. The method featured no metal catalyst, broad substrate scopes and high yields. Besides, a radical mechanism was proposed in the reaction process. Additionally, most of target compounds exhibited potent anti-proliferative activities against MCF-7 and Hela cells. [ABSTRACT FROM AUTHOR]

The palladium(II)-catalyzed direct oxidative C–H olefination of readily available N -tosylacrylamides and allenoates for the synthesis of dienyl esters is described. The amide and ester moieties both act as the directing groups for the regio- and the stereo-controlled C–H functionalization/cyclization, which was proved by DFT calculations. Molecular oxygen was used as the terminal oxidant in the approach, rendering the reaction more sustainable. [ABSTRACT FROM AUTHOR]

Thiourea-based hydrogen bond donor has been recently disclosed by our group to be an efficient organocatalyst for cross-dehydrogenative coupling (CDC) reactions. Here we present a detailed mechanistic study of this reaction using NMR spectroscopy and kinetic isotope effect experiment. The results revealed that α-amino peroxide is the true intermediate within the catalytic cycle, formed via a thiourea-catalyzed rate-determining hydrogen atom transfer (HAT) process. These experimental investigations not only provide somewhat insight into the mechanism of thiourea-catalyzed CDC reactions but also promote their further applications. [ABSTRACT FROM AUTHOR]

The ruthenium(II)-catalyzed site-selective acylation of indolinic C−H bonds with ethyl glyoxalate is described. A cationic ruthenium catalyst in the presence of copper(II) acetate was found to be an optimal catalytic system for the construction of C7-indolinyl ketoesters. In this process, C−H addition reaction first takes place, and subsequent oxidation of alcohol intermediates occur in-situ. The formed C7−functionalized indolines can be a crucial array towards the construction of novel bioactive molecules. [ABSTRACT FROM AUTHOR]

Transition-metal-catalyzed oxidative C–H olefination/annulation reactions are among the most attractive topics in organic synthesis to construct heterocyclic compounds. The challenge is that, in order to achieve satisfied catalytic efficiencies, most of these syntheses employed stoichiometric oxidants. Herein, we report a Pd(II)/LA-catalyzed (LA: Lewis acid) oxidative C–H olefination/annulation reaction of N -Ts-2-arylanilines with activated olefins to synthesize dihydrophenanthridines by using dioxygen balloon as the sole oxidant source, and the presence of LA sharply improved the catalytic efficiency of Pd(OAc) 2. The mechanistic studies by using in situ generated palladacycle compound as the catalyst for the substrate H/D exchange disclosed that the C–H activation by Pd(II) was a reversible step. However, in the catalytic C–H olefination/annulation reaction, whether deuterium from solvent being incorporated into the recycled substrate was highly dependent on the aromatic electronic effect of the substrates. [Display omitted] [ABSTRACT FROM AUTHOR]

In recent decades, cobalt catalyst has represented a powerful strategy for developing common organic reactions. This review includes the most recent efforts of Co catalysts applications in selective organic reactions such as C–H & C—X activation, hydrogenation & dehydrogenation, and cycloaddition. The contribution of cobalt salt or earth-abundant cobalt complexes usually accomplishes these reactions. It mainly involves different fundamental reaction paths, such as the concerted metalation-deprotonation (CMD) path associated with non-oxidative C–H activation and the intermolecular single-electron transfer (SET) path. Here, we summarize the advances of Co catalyst applications in three main sections: (i) C–H & C—X activation, (ii) hydrogenation-dehydrogenation, and (iii) cycloaddition. The characteristics of each catalyst are discussed according to parameters such as efficiency, recyclability, catalyst life, lack of catalyst nanoparticles agglomeration, and required time of catalyst effects on the reactions. [Display omitted] [ABSTRACT FROM AUTHOR]

Catalytic C–H activation and transformation has received tremendous attention. This Perspective focuses on recent advances in C–H functionalization with alkenes, allenes, and alkynes by half-sandwich rare-earth catalysts, including asymmetric transformations. The reaction generally proceeds through formal C–H addition to unsaturated C–C bonds, thus constituting a 100% atom-efficient route for the construction of new C–C bonds. Future outlooks in related areas are also described. [Display omitted] [ABSTRACT FROM AUTHOR]

The Catellani reaction is a palladium-catalyzed hydrocarbon-activated multicomponent tandem reaction involving an aryl halide, an electrophilic coupling reagent and a terminating reagent. It must be mentioned that norbornenes act as co-catalysts play critical roles in Catellani reaction. After more than two decades of development, the reaction has evolved into a unique method for the building of polyfunctionalized aromatics from easily accessible starting materials, incorporating not only the advantages of cross-coupling and adjacent metallization, but also excellent reactivity and wide applicability. This manuscript reviews the important advances of Catellani reactions over the last 4 years, which would be valuable for the researchers interested in this prosperous research area. [Display omitted] [ABSTRACT FROM AUTHOR]

A practicable and efficient C–H activation approach for the synthesis of indoline using palladium as the catalyst and tert -butyl peroxybenzoate as the oxidant was firstly reported. A broad range of phenethylamine derivatives with diverse functional groups were well tolerated. Moreover, late-stage diversification of the indoline could proceed successfully and corresponding bioactive molecules were achieved in good yields. [Display omitted] [ABSTRACT FROM AUTHOR]

In the area of synthetic chemistry, there are various examples of inexpensive, highly abundant and less toxic transition-metal catalyzed inert C–H bond activation reactions. These reactions extended a productive test ground for the synthesis of biologically active heterocycles along with various beneficial structural motifs. Most of the C–H bond activation reactions deal with facile additions or functionalizations. In the last two decades, the less expensive and more abundant 3 d-transition metal cobalt has emerged as an effectual option for highly expensive noble metals of second and third-row. These alkenylation/annulation reactions provide highly important cyclic derivatives from easily accessible compounds in an expenditious and sustainable fashion. The aim of this review article is to highlight the power of cobalt metal catalyst in the C–H bond activation reactions involving alkyne species. [Display omitted] [ABSTRACT FROM AUTHOR]

Cobalt-catalyzed reactions of triazoles and dioxazol-5-one involving nitrene transfer were described. A number of amidated 1,2,3-trizole derivatives have been obtained in moderate to excellent yields. [ABSTRACT FROM AUTHOR]

A formal synthesis of (+)-steganone by means of atroposelective C–H activation is reported. The herein described strategy is very straightforward as the targeted scaffold is afforded in only 10 steps, amongst which five of them are conducted without isolation of the crude products. Accordingly, the final product is isolated in remarkable overall yield of 42,3% and with an enantiomeric excess above 98% without need for any expensive chemicals and catalysts. All catalytic steps may be performed at multi gram scale. [ABSTRACT FROM AUTHOR]

A strategy for the total synthesis of maoecrystal V is presented. The key interior vicinal quaternary carbon centers will be formed via sequential bridgehead C–H bond insertion and enolate functionalization. Studies herein validate the C–H bond insertion as feasible in model studies, though there are significant effects on the selectivity for the bridgehead position from neighboring groups. Both inductive electron withdrawing elements and sterics play a role in deactivating that position, with the former having a greater effect. Forming the second quaternary carbon is possible via enolate acylation and alkylation. Lastly, an approach to synthesize the cyclohexenone ring of maoecrystal V is described. [ABSTRACT FROM AUTHOR]

A novel and efficient synthesis of isatins from α -hydroxy amides via ruthenium-mediated aromatic C–H activation is described. The reactions proceeded smoothly under mild conditions and generated the corresponding products in good to excellent yields. This methodology has a broad substrate scope and opens up an interesting and attractive avenue for the application of intramolecular ortho -C–H activation. [ABSTRACT FROM AUTHOR]

A practical ortho C–H olefination of phenyl acetic acid derivatives was achieved with a 1,2,3-triazole auxiliary directing group. Good to excellent yields were achieved with O 2 as terminal oxidant. Other bidentate directing groups, such as 8-aminoquinoline, gave poor reactivity under this aerobic condition, highlighting the unique reactivity of triazole in promoting C–H activation. [ABSTRACT FROM AUTHOR]

A Rh(III)-catalyzed aromatic C–H bond carbenoid functionalization of triazenes by α-diazomalonates has been developed, with features of mild reaction condition and high efficiency. Furthermore, the functionalized triazenes could be subject to divergent synthesis. [ABSTRACT FROM AUTHOR]

Several vinylazulenes containing metalophilic groups were prepared as potential host molecules in ligands for metal ion detectors. The azulene-1-carbaldehyde derivatives were condensed with methylene active compounds in the presence of piperidine. The reaction is influenced by both the nature of the methylene activating groups and by the presence of the alkyl groups on the 4-,6- or 8- position of the azulene moiety. Some unusual reagents, as nitroacetate were condensed with imines activated by acetic anhydride. Several autocondensation azulenic products were evidenced in the presence of weak activated methylenes. Considerations regarding S 1 and S 2 absorption bands of the azulene compounds were revealed and correlated with frontier molecular orbitals. At the same time, the prepared ligands redox potentials were investigated by differential pulse voltammetry (DPV). [ABSTRACT FROM AUTHOR]

In this paper, a rhodium-catalyzed reaction of 2-arylquinazolin-4-ones with acrylates is described, leading to pyrrolo[2, 1- b ]quinazolin-9(1 H )-one derivatives with high efficiency and good tolerance of functional groups. In the reactions, it is believed that tandem C–H activation and aza-Michael addition are involved. [ABSTRACT FROM AUTHOR]

A palladium N -heterocyclic carbene [Pd(NHC)Cl 2 ] complex of Vitamin B 1 developed earlier in our lab was also found to be an effective catalyst for regioselective thiolation via C–H bond activation of 1-aryl-3-methyl-1 H -pyrazol-5(4 H )-ones 1a – c using aryl thiols 2a – e . The protocol was found to be simple, efficient and highly regioselective to afford the target products 3a – o in good to excellent yields. [ABSTRACT FROM AUTHOR]

The rhodium(III)-catalyzed mild and site-selective C–H allylation of 2-arylbenzo[ d ]thiazoles and 2-arylbenzo[ d ]oxazoles with allylic phosphonates and allylic carbonates is described. This transformation provides an efficient construction of C2-allylated, crotylated and prenylated 2-arylbenzo[ d ]thiazoles and 2-arylbenzo[ d ]oxazoles. In addition, this protocol can be applied to the formation of 2-arylbenzo[ d ]thiazole scaffolds containing an allylic alcohol group by using of 4-vinyl-1,3-dioxolan-2-one and vinyl oxirane as coupling partners. [ABSTRACT FROM AUTHOR]

Quinazoline was used as a directing group for palladium-catalyzed ortho-mono-arylation of 2,4-disubstituted quinazoline via C–H bond activation. The reaction proceeded well with a broad substrate scope in a highly regioselective manner to provide a direct way to access highly functional quinazoline core structure derivatives. [ABSTRACT FROM AUTHOR]

An efficient and general protocol for palladium-catalyzed chelation-assisted ortho -nitration of 2-arylbenzoxazoles has been developed. This nitration exhibits high regioselectivity for the substrates, and the reaction could tolerate many functional groups such as F, Cl, Br, CH 3 , CH 3 O, affording ortho -nitration products in moderate to good yields. Moreover, some 2-arylbenzoxazole heterocyclic analogues proceed well under this catalytic system. Further studies have been performed to obtain insight into the mechanism. [ABSTRACT FROM AUTHOR]

A Rh(III)-catalyzed aldehyde C–H bond functionalization of salicylaldehydes with arylboronic acids has been developed, with features of mild reaction condition and high efficiency. Furthermore, the functionalized 2-hydroxybenzophenone could be subject to divergent synthesis of heterocycles. [ABSTRACT FROM AUTHOR]

A series of naphtho[1′,2′:4,5]imidazo[1,2- a ]pyridines were synthesized smoothly from 2-arylimidazo[1,2- a ]pyridines and alkynes involving rhodium(III)-catalyzed C–H bond functionalization. The process selected Co(OAc) 2 ·4H 2 O as the co-catalyst for the first time and minimized the reaction time to 2 h under air atmosphere. Some products exhibited deep blue luminescence properties. [ABSTRACT FROM AUTHOR]

The reactions of indole ( 1 ) with iodotoluene in the presence of norbornene or dicyclopentadiene led to the formation of indole derivative ( 2a ). It is through the C–H activation at ortho -position of indole by Catellani-type reactions. Besides, several palladium complexes ( 4a , 4b , 5a , 5b , 6a , and 6b ), containing either single or double norbornene or dicyclopentadiene fragments via insertion into the Pd–C(aryl) bond of the formerly formed palladium-containing intermediate, were obtained and characterized by spectroscopic means as well as by X-ray diffraction methods. The ratios of 2a to 5a could be altered by employing different palladium sources. Triple insertion of norbornene or dicyclopentadiene into the Pd–C(aryl) bond was not observed. [ABSTRACT FROM AUTHOR]

Developments are reported in the catalytic synthesis of biaryls containing an ortho -carbaldehyde or 6 H -dibenzopyrans in the presence of palladium/norbornene as catalyst. The reaction of o -substituted aryl iodides and o -bromobenzyl alcohols proceeds by unsymmetrical aryl-aryl coupling to form a seven-membered oxapalladacycle intermediate, which may undergo an intramolecular redox process to form carbonyl groups or a C–O coupling to six-membered cyclic ethers. The predominant formation of dibenzopyrans as well as of biaryl structures containing the oxidized CHO group in one ring and the reduced CH 2 OH in the other is described along with some mechanistic insights. [ABSTRACT FROM AUTHOR]

Ruthenium(II) carboxylate complexes allowed for efficient cross-dehydrogenative alkenylations of N -aryl-1,2,3-triazoles. The twofold C–H functionalizations occurred with excellent chemo-, regio-, site- and diastereoselectivities, and ample substrate scope. The versatile ruthenium(II) catalyst proved tolerant of moisture, air, and various electrophilic functional groups. Mechanistic studies were in good agreement with an initial C–H metalation by a cationic ruthenium(II) carboxylate, along with a subsequent migratory insertion of the olefin. [ABSTRACT FROM AUTHOR]

The utility of Cp ∗ Co(III)-catalysts was expanded to oxidative C–C bond-forming reaction. In situ-generated Cp ∗ Co(III)-catalyst, rather than a preformed cationic Cp ∗ Co(III)-complex, was effective. Oxidative alkenylation of benzamides and acetanilide with ethyl acrylate proceeded with silver acetate as a stoichiometric oxidant, giving products in up to 93% yield. [ABSTRACT FROM AUTHOR]

The rhodium(III)-catalyzed selective C–H allylations of indolines and indoles with 4-vinyl-1,3-dioxolan-2-one at room temperature are described. These transformations provide the direct and efficient formation of indolic scaffolds containing an allylic alcohol group. [ABSTRACT FROM AUTHOR]

An unprecedented direct ortho C–H arylation and chlorination of α-ketoesters were successfully accomplished by using a combination of monodentate transient directing group strategy and palladium catalysis. The in situ formed imine changed the bidentate coordination model of α-ketoesters to monodentate, so as to fulfill the ortho C–H activation. Importantly, the key binuclear cyclopalladium intermediate bridged by acetate anion was unambiguously characterized by X-ray diffraction, which solidly supports the proposed mechanism. The practical utility was further depicted as facile access to oral antiplatelet agent Clopidogrel racemate via subsequent two-step derivatization. [Display omitted] [ABSTRACT FROM AUTHOR]

The synthesis of picolinamides through Ritter reaction of 2-cyanopyridine with alcohols and alkenes is reported. Moreover, a range of additional heteroaryl nitriles successfully participate in the amidation reaction. Salient features of the reaction include the operational simplicity and the inexpensive reagents used. The synthetic utility of a camphene derived picolinamide is demonstrated through a palladium-catalyzed C–H arylation reaction. [Display omitted] [ABSTRACT FROM AUTHOR]

Idebenone was synthesized directly by free-radical alkylation of 2,3-dimethyl-1,4-benzoquinone (Coenzyme Q 0 ) with commercially available 11-hydroxyundecanoic acid in the presence of potassium peroxodisulfate and silver nitrate in a mixed solvent (CH 3 CN–H 2 O, 1:1) under mild condition in good yields (65%, based on Coenzyme Q 0 ). The reaction is operationally simple and could be used in the preparation of other biologically Coenzyme Q analogues. [ABSTRACT FROM AUTHOR]