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The stereodivergent asymmetric synthesis of 2,5‐trans/cis pyrrolidines by 1,3‐dipolar cycloaddition using two different types of activated alkenes is described. When ylidene‐isoxazolones were employed as dipolarophiles, the Ag/(S,Sp)‐iPr‐FcPHOX‐catalyzed asymmetric [3+2] cycloaddition of imino lactones proceeded with 2,5‐trans selectivity. Subsequent decarboxylation of the isoxazolone rings produced pyrrolidines with 2,5‐trans stereoretention. In the reaction using acyclic enones as activated alkenes, the Ag/(R,Sp)‐ThioClickFerrophos complex‐catalyzed asymmetric [3+2] cycloaddition afforded 2,5‐cis substituted pyrrolidines in high yields and enantioselectivities. Therefore, these methods can be considered as a formal stereodivergent synthesis of 2,5‐cis/trans pyrrolidines. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) was used to investigate the three-component coupling reactions of aldehydes, alkynes, and amines (A3 coupling) using N-heterocyclic carbene silver as the catalyst. This study reveals that the addition reaction between the catalyst N-heterocyclic carbene silver and phenylacetylene (PAE) forms Ag_PAE. Subsequently, one hydrogen atom of the Ag_PAE migrates to the nitrogen atom of the Amine. Thereafter, the amine aldehyde condensation reaction generates a molecule of water and an imine ion with (Path one) or without (Path two) another amine catalyst. Path one has a lower reaction barrier than Path two. Subsequently, the imine ion reacts with silver phenylacetylide to generate the A3 coupling reaction product propargylamine (PPA). Furthermore, the triple bond and −N3 group in PPA undergo a cycloaddition reaction and generate the final product (PR). The entire reaction is strongly exothermic, and, therefore, the reaction is easy to conduct. Moreover, conceptual density functional theory calculations confirm the reaction mechanism. Investigating the mechanism of these reactions will be helpful for understanding and developing new synthesis strategies for similar functional compounds. [ABSTRACT FROM AUTHOR]

A series of spirocyclic pyrrolidine derivatives with quaternary stereocenters was constructed via asymmetric [3 + 2] cycloaddition reactions between imino esters and 2-oxindole. By ingenious use of ligands on the silver catalyst allows stereoselectivity to either endo -isomers (ee up to 98 %, yields up to 96 %) with (R , Rp)-Ph-Phosferrox or exo -isomers (ee up to 99 %, yields up to 87 %) with (R)-BINAP. This work is notable for its high yields, broad substrate adaptability and excellent enantioselectivity. [Display omitted] • This methodology offers an efficient pathway for the concurrent synthesis of spirocyclic pyrrolidine derivatives containing a tetradentate stereocenter through exocyclic addition and endocyclic addition. • By ingenious use of ligands on the silver catalyst allows stereoselectivity to either endo-isomers (ee up to 98 %, yields up to 96 %) with (R, Rp)- Ph-Phosferrox or exo-isomers (ee up to 99 %, yields up to 87 %) with (R)-BINAP. • Efficient catalytic synthesis of chiral molecules has been realized. [ABSTRACT FROM AUTHOR]

A novel approach for the synthesis of regioselective pyrano[3,4‐b]quinolines from 3‐alkynylquinoline aldehydes with alcohols as nucleophiles has been elucidated. This protocol has shown high generality of functional group and provides the pyrano‐annulated products good to excellent yields. This methodology was adopted a new synthetic strategy to develop the 3‐alkynylquinolinealdehydes by using methanol as a C1 source. [ABSTRACT FROM AUTHOR]

A variety of chiral nine‐membered N‐heterocycles were prepared in moderate to good yields with high diastereoselectivity through a silver(I)‐catalyzed [3+2] cycloaddition and [3,3]‐rearrangement of N‐vinyl‐α, β‐unsaturated nitrones and chiral 3‐propioloyloxazolidin‐2‐ones. Experimental studies showed that silver catalyst promoted the cycloaddition and rearrangement process, and the stereochemistry of the nine‐membered N‐heterocycles was controlled via [3,3]‐rearrangement by chiral oxazolidinone‐auxiliary through a boat‐like transition state. Moreover, the obtained nine‐membered N‐heterocycle diastereomers were converted to chiral pyrrolizines with high diastereoselectivity and pyrrolizine carboxylate was obtained in 54% yield with 90% ee by the removal of chiral auxiliary. [ABSTRACT FROM AUTHOR]

ortho‐Carbonylarylacetylenol, can be utilized for the synthesis of several important core structures. In this work, a method is developed for the diastereoselective synthesis of spirocyclic ethers using a silver catalyst under the presence of acid. This protocol can be applied to a variety of substrates resulting in the corresponding products in 35–97% yields with good diastereoselectivity. The proposed reaction mechanisms and stereoselectivity outcome of the corresponding products are investigated using DFT calculation. This current protocol can be applied to a broad range of substrates which would be useful for the creation of libraries of spirocylic ethers [ABSTRACT FROM AUTHOR]

Silver complexes with 5‐(4‐(tert‐butyl)‐1H‐imidazol‐1‐yl)‐imidazo[1,5‐a]pyridin‐3‐ylidene ligands were synthesized as metal‐imidazole acid‐base cooperative catalysts. Single crystal XRD analysis revealed that the silver atom was located in the vicinity of the imidazole ring and that cationic silver complexes formed dimers through coordination between the silver metal and the imidazole pendant. These cationic silver complexes served as catalysts for cyclization of alkyne‐tethered carboxylic acids. NMR experiments indicated that the dimeric cationic silver complex dissociated to a monomer upon protonation of the imidazole moiety, resulting in coordination of an acetonitrile to the silver atom. DFT calculations supported the acid‐base cooperative action of the silver‐imidazole for the efficient alkyne‐carboxylic acid cyclization. [ABSTRACT FROM AUTHOR]

Strain‐promoted azide–alkyne cycloaddition using dibenzoazacyclooctyne (DBCO) is widely applied in copper‐free bioorthogonal reactions. Reported here is the efficient acid‐promoted rearrangement and silver‐catalyzed amidation of DBCO, which alters its click reactivity robustly. In the switched click reaction, DBCO, as a caged acylation reagent, enables rapid peptide/protein modification after decaging facilitated by silver catalysts, rendering site‐specific conjugation of an IgG antibody by a Fc‐targeting peptide. [ABSTRACT FROM AUTHOR]

A silver‐catalyzed carbocyclization of azide‐tethered alkynes has been developed for the synthesis of polysubstituted quinolines in good to high yields. Mechanistic studies indicate that this reaction is initiated by a silver‐catalyzed 6‐endo‐dig azide‐yne cyclization, followed by a formal R−X (X=Cl, Br, or I) insertion with external halide through a ylide intermediate. The salient features of this reaction include readily available materials, inexpensive silver‐catalyst, mild reaction conditions, good functional group tolerance, and ease in further transformations. [ABSTRACT FROM AUTHOR]

A new route for the expedient synthesis of a specific regioisomer of isoquinoline-fused quinazolinones is reported. Silver(I)-catalyzed cascade cyclization of 2-aminobenzamides and 2-alkynylbenzaldehydes followed by in situ oxidation gives 12-butyl- or 12-aryl-6Hisoquinolino[ 2,1-a]quinazolin-6-ones in 69-91% yields. The structure of the isoquinoline-fused quinazolinone was confirmed by X-ray crystallography analysis. [ABSTRACT FROM AUTHOR]

Herein, a silver and copper co-catalyzed cascade intramolecular cyclization/desulfinamide/dehydrogenation reaction for the synthesis of substituted carbazoles is reported. This reaction, which involved formation of new C–C and C–N bonds as well as C–N bond cleavage, afforded diverse carbazoles in high yields and showed good functional group tolerance. [ABSTRACT FROM AUTHOR]

A class of multifunctional amidophosphanes derived from chiral 1,2-diphenylethylenediamines and natural α-amino acids has been developed. Among these, in combination with silver(I) salts, a chiral secondary amine-amidophosphane precatalyst has been demonstrated as being a highly efficient multifunctional precatalyst in the asymmetric 1,3-dipolar cycloaddition of azomethine ylides, including a series of heterocyclic, aliphatic, and 2-substituted azomethine ylides, and aromatic α,ß-unsaturated aldehyde derived imino esters with different electron-deficient alkenes, as well as the three-component reaction of α-imino esters generated in situ by using N,N'-diisopropylcarbodiimide as dehydrating agent. Under optimal conditions, highly functionalized endo-adducts were obtained in high to excellent yields (up to 99% yield) and enantioselectivities (up to >99.9% ee). [ABSTRACT FROM AUTHOR]

A highly diastereo- and enantioselective silver-catalyzed azomethine ylide-imine (AYI) cycloaddition reaction of glycine aldimino esters with imines was developed in which the Xing-Phos-controlled syn-selective or DTBM-Segphos-induced anti-selective AYI cycloaddition reaction could be applied to the synthesis of a variety of stereodivergent 1-alkyl-2,5-substituted imidazolidines with high yields and excellent enantioselectivities (up to 99% ee) as well as good diastereoselectivities (up to 99:1 dr) under mild reaction conditions. [ABSTRACT FROM AUTHOR]

An efficient Ag(I)-catalyzed p-acid activation method for the cyclization of cyclic ketimine-tethered ynones is reported. Various nitrogen-containing scaffolds commonly found in bioactive alkaloids can be prepared in high yields, and the utility of the method is demonstrated by a formal synthesis of (±)-lasubine II and in a short total synthesis of (±)-indolizidine 209D. [ABSTRACT FROM AUTHOR]

Abstract: We present a silver‐catalyzed reaction of acceptor‐enynals with alkynes to assemble tetracyclic framework of fluorenols efficiently, in which the reaction was proposed to proceed through an unfavorable 6‐endo‐dig cyclization, followed by a tandem [4+2] cycloaddition/Friedel–Crafts reaction. The reaction could be conducted in one pot for diaryl alkynes substrates. For terminal aryl alkyne or arylalkyl alkyne substrates, the Friedel–Crafts reaction has to be performed in the absence of alkynes. The control reactions demonstrated that there was competition between [Ag]⋅⋅⋅alkyne and [Ag]⋅⋅⋅O=CR2. [ABSTRACT FROM AUTHOR]

We report on the surface-catalyzed formal [2+2] and [2+2+2] cycloadditions of ortho-activated tetracene species on a Ag(111) substrate under ultrahigh vacuum conditions. Three different products are obtained: tetracene dimers, trimers, and tetramers. The former results from the formation of a four-membered ring while the other two arise from cyclization into six-membered rings. These on-surface reactions have been monitored by scanning tunneling microscopy and rationalized by density functional theory calculations. Our approach, based on the reaction of ortho-dihalo precursor monomers via formal cycloadditions, establishes an additional method for the highly active field of on-surface synthesis and enables the development of novel 1D and 2D covalent carbon nanostructures. [ABSTRACT FROM AUTHOR]

The use of a well-chosen catalyst is instrumental for the development of more efficient, economical and environmentally friendly reactions. In recent decades, indium-based catalysts have proven to be competitive and useful alternatives to transition-metal catalysts such as silver and gold. In this short review, we present some of the recent advances in indium(III)-catalyzed transformations of alkynes, with a focus on cyclization reactions. [ABSTRACT FROM AUTHOR]

A facile silver-catalyzed decarboxylative radical addition/cyclization reaction of α,α-difluoroarylacetic acids and acrylamides has been disclosed. The method provides a highly attractive approach to synthesize a series of difluorinated oxindoles that contain various functional groups in moderate to good yields under mild conditions. Moreover, experimental studies reveal that the CF2 group of the α,α-difluoroarylacetic acids plays a vital role in the transformation. [ABSTRACT FROM AUTHOR]

Silver-catalyzed on-water intramolecular cyclization of acetylenic free amines is reported, which affords 7-azaindoles in good to excellent yields. Neither strong base/acid catalysts nor N-substituted substrates are required to achieve this cycloisomerization. Hydrogen bonds between water medium and the substrates play an important role in improving chemical reactivity and regioselectivity. Furthermore, the on-water reaction is extendable to acetylenic amides for isoquinolone synthesis. [ABSTRACT FROM AUTHOR]

A silver-catalyzed aerobic oxidative [3+2] cycloaddition of azomethine ylides with aryl or heteroaryl isocyanides has been developed. The reaction represents a novel protocol for the efficient and practical synthesis of 1,2-diarylimidazoles bearing a broad range of substituents in good to excellent yields under mild conditions. The practicability of this cycloaddition was shown by a gram-scale synthesis and a double cycloaddition for the construction of highly conjugated polyarylimidazole systems. [ABSTRACT FROM AUTHOR]

A convenient protocol for the synthesis of sulfonylated benzofurans via Ag-catalyzed oxidative cyclization has been established. Chemically stable and easily available sodium sulfinates were used as the sulfonylation reagents and building block for the heterocycle construction. With this novel strategy, various benzofurans bearing dual functional groups could be obtained in good yields with high chemo- and regioselectivities under mild conditions. [ABSTRACT FROM AUTHOR]

The full details of the original Ag-catalyzed domino oxidative cyclization reactions of unprotected 2-alkynylanilines with Oxone are described. The influences of several parameters including the substrate features, oxidant, reaction conditions, and catalyst on the reaction outcome were explored. A plausible mechanism is provided for the unusual silver-catalyzed oxidative cyclization reactions of 2-alkynylanilines to anthranils. [ABSTRACT FROM AUTHOR]

N-Tosylimines and lithiated alkoxyallenes afforded the corresponding allenyl N-tosylamines in good to excellent yields. The 5-endo-trig cyclizations of these intermediates to 2,5-dihydropyrrole derivatives were achieved under strongly basic conditions with potassium tert-butoxide or under milder conditions with either silver(I) or gold(I) catalysis. In general, gold chloride catalyzed reactions occurred with the lowest catalyst loadings and delivered the best yields. With phenyl-substituted 2,5-dihydropyrrole, we investigated typical reactions such as oxidative and reductive transformations. The acid-promoted hydrolysis of the enol ether moieties of three 2,5-dihydropyrroles furnished the corresponding pyrrolidin-3-ones, which were reduced to give 3-hydroxypyrrolidine derivatives in good yields. The aromatization of 2,5-dihydropyrroles to 3-methoxypyrrole derivatives was accomplished by base treatment, which caused the elimination of p-tolyl sulfinate. Electron-rich pyrrole derivatives were synthesized in good yields even on a large scale. All of the experiments illustrate the efficacy and flexibility of the alkoxyallene approach to pyrrole derivatives. [ABSTRACT FROM AUTHOR]

The [2+1] cycloaddition of alkynes with diazo compounds represents one of the most powerful and reliable methods for the construction of cyclopropenes. However, it remains a formidable challenge to accomplish the cyclopropenation of alkynes with non-stabilized diazoalkanes, owing to the fact that such compounds are unstable and prone to detonation. Herein, we report a general silver-catalyzed cyclopropenation reaction of alkynes with unstable diazoalkanes, by for the first time the discovery and application of N-nosylhydrazones as room-temperature decomposiable diazo surrogates. This method allows for the efficient assembly a wide variety of cyclopropene derivatives that are otherwise difficult to access by conventional methods. [ABSTRACT FROM AUTHOR]

An unexpected silver-catalyzed cascade reaction of β-enaminones and isocyanoacetates affording functionalized pyrrole derivatives is reported. In this reaction, tautomeric equilibria of β-enaminones are utilized to generate imine partners in situ. A hypothesized sequential Mannich addition/cyclization of imine tautomers and isocyanoacetates followed by an unprecedented ring-opening of the resultant 2-imidazolines and dehydration–condensation deliver the final 1,2,4,5-tetrasubstituted pyrrole products. [ABSTRACT FROM AUTHOR]

A Ag-catalyzed phosphorus radical promoted cyclization of cinnamamides to give exclusively 2-phosphinoyl-3H-pyrrolo[1,2-a]indoles derivatives via a 5-endo-trig manner is described. This novel reaction leads to the simultaneous formation of C-C and C-P bonds in one step with excellent chemo- (only 5-endo) and diastereoselectivity (dr >20:1) under mild conditions in moderate to good yields. [ABSTRACT FROM AUTHOR]

An interesting silver(I)-catalyzed, one-pot intramolecular cyclization of epoxide-propargylic esters is described. A variety of 1,4-oxazine derivatives were obtained through a novel domino sequence, including three-membered ring-opening, 3,3-sigmatropic rearrangement, 6- exo-cycloisomerization and subsequent intramolecular elimination in moderate yields under mild conditions. [ABSTRACT FROM AUTHOR]

Pyrimidinone is one of the important nitrogen containing heterocycles due to their wide range of bioactivities. An efficient silver-catalyzed intermolecular cyclization of 2-aminopyridines with various alkynoates has been developed. 2-Substituted 4 H -pyrido[1,2- a ]pyrimidin-4-ones containing a wide range of functional groups are synthesized in the standard conditions. This transformation is conducted under convenient conditions and affords products in good yields. [ABSTRACT FROM AUTHOR]

The combined chemistry of silver and isocyanides is unique in performance, proved with the number of recent achievements. With the aim of triggering further research in this field, this review assembles and comprehensively summarizes the silver-based reactions of isocyanides. In this review, we especially emphasize the uniqueness of silver catalysis in the activation of isocyanides, the reaction selectivity, and the mechanistic description. [ABSTRACT FROM AUTHOR]

A silver-catalyzed highly enantioselective 1,3-dipolar cycloaddition reaction of α-silylimines with pyrone-based trisubstituted olefins was developed affording bi- and tricyclic α-quaternary-carbon-rich pyrano-pyrrolidines in excellent yields. The tricyclic benzopyrone adducts thus obtained were efficiently transformed into highly complex tetracyclic scaffolds supporting four consecutive stereogenic centers with three quaternary carbons. [ABSTRACT FROM AUTHOR]

A series of high-yielding silver(I)-catalyzed cyclization reactions of pyridine-, isoquinoline-, and pyrazine-ynones are described. The operationally simple and mild reaction conditions are a significant improvement over previously reported thermal cyclizations. The quinolizinone products were also used in a novel dearomatization strategy to prepare 0.53 g of the alkaloid lasubine II in five steps and 36% overall yield. [ABSTRACT FROM AUTHOR]

(-)-Berkelic acid is an architecturally unique secondary metabolite isolated from an extremophilic Penicillium species. In this paper, we describe a very simple protocol to construct the central core of this natural product. Using this strategy, not only (-)-berkelic acid, but also a small library of analogues has been accessed. The key point of our protocol is a remarkable silver-catalysed cascade reaction that allows the assembly of the core of the natural product in a single step and from two simple starting materials, a 4-pentynol derivative and an ortho-alkynylsalicylaldehyde. The cytotoxicity of our synthetic (-)-berkelic acid and some analogues against two cancer cell lines, OVCAR-3 and SSCC38, was evaluated. [ABSTRACT FROM AUTHOR]

A silver-catalyzed tandem reaction of TosMIC with 2-methyleneindene-1,3-diones was developed for the direct synthesis of benzo[ f ]indole-4,9-diones. In this reaction, a domino [3+2]-cycloaddition/imidoyl anion cyclization/ring opening of cyclopropanolate/aromatization is proposed and three C C bonds are formed successively. [ABSTRACT FROM AUTHOR]

The first cyclization reaction between vinyl azides and N-sulfonyl-1,2,3-triazoles is reported. A Rh/Ag binary metal catalyst system proved to be necessary for the successful cyclization. By varying the structure of vinyl azides, such reaction allows the divergent synthesis of pyrroles and 2 H-pyrazines. The cyclization reactions feature a broad substrate scope, good functional group tolerance, high reaction efficiency, and good to high product yields. [ABSTRACT FROM AUTHOR]

An efficient synthesis of symmetrical 3, 3′-bisindolylarylmethanes with various substituents on the indole moiety has been developed by Ag(I)-catalyzed cycloisomerization and an deoxygenative addition sequence on o-alkynylanilines and aryl aldehydes. Ag(I) is proposed to activate alkyne unit and carbonyl moiety simultaneously leading to a domino first 5-endo-dig indole annulation, addition to CO, second indole annulation, and its dehydroxylative addition. [ABSTRACT FROM AUTHOR]

Imidazole ring is an important five-membered aromatic heterocycle that is widely present in natural products and synthetic molecules. The isocyanide-isocyanide [3+2] cross-cycloaddition reaction constitutes a straightforward method to access imidazoles starting from the easily available chemicals. So far, only three successive reports are known and all lead to the formation of 1,4-disubstituted imidazoles. Here, we report the first isocyanide-isocyanide [3+2] cross-cycloaddition reaction allowing for the formation of 1,4,5-trisubstituted imidazoles under silver catalysis. An unexpected 1,2-migration of sulfonyl, alkoxycaybonyl, and carbamoyl groups took place during the cyclization process that is responsible for the formation of trisubstituted imidazoles. This report displayed a mechanistically novel synthetic method toward a variety of imidazole derivatives, which are otherwise difficult to access by conventional methods. [ABSTRACT FROM AUTHOR]

A silver-catalyzed cycloisomerization reaction of a series of o-alkynylbenzohydroxamic acids is reported. Several 5-exo-dig and 6-endo-dig modes of cyclization were observed with the nitrogen or oxygen atoms of the amide group acting as nucleophiles. The selectivity was strongly dependent on the silver salt used and on the presence of triphenylphosphine as an additive. Indeed, while the use of Ag2O at room temperature allowed the isolation of isobenzofuran-1-one oximes (7 compounds, 48-92% yield), [Ag(Im)]n with the concomitant addition of 2 equiv of PPh3 led to a switch in selectivity and to a family of isoindolin-1-ones (10 compounds, 59-87%). [ABSTRACT FROM AUTHOR]

The enantioselective Taniaphos·silver fluoride-catalyzed enantioselective 1,3-dipolar cycloaddition using 2,2-dimethoxyacetaldehyde derived imino esters and maleimides is described. The employment of this complex allows the reaction in the absence of an extra base giving high yields and ee of the corresponding endo- cycloadducts. Calculations performed at B3LYP/6-31G*&LANL2DZ level of theory predicted the expected absolute stereochemistry for both BINAP and Taniaphos·silver fluoride-mediated cycloadditions, as well as the enantioselectivity and mild conditions of the reaction. [ABSTRACT FROM AUTHOR]

A dearomatization strategy has been developed for the efficient construction of vertically expanded five-ring fused benzofurans from ortho-alkynylphenols and ortho-alkynylarylaldimines. The stepwise procedure comprises a dearomatization-induced silver-catalyzed [3 + 2] cycloaddition followed by an aromatization-triggered ytterbium-catalyzed rearrangement. [ABSTRACT FROM AUTHOR]

The synthesis of constrained spirocycles is achieved effectively by means of 1,3-dipolar cyclodditions employing α-imino γ-lactones as azomethine ylide precursors and nitroalkenes as dipolarophiles. The complex formed by (R,R)-Me-DuPhos 18 and AgF is the most efficient bifunctional catalyst. Final spiro-nitroprolinates cycloadducts are obtained in good to moderate yields and both high diastereo- and enantioselectivities. Density functional theory (DFT) calculations supported the expected absolute configuration as well as other stereochemical parameters. [ABSTRACT FROM AUTHOR]

A silver catalyzed cyclization of acetylene amine was developed to synthesize 4,6-substituted pyrrolo[3,2- d ]pyrimidine, a bioactive isosteric scaffold of purine. Starting from simple commercially available acetylenes and pyrimidines, the method was found to be compatible with wide chemical functionalities, leading to a series of pyrrolo[3,2- d ]pyrimidines in 84–91% yields. [ABSTRACT FROM AUTHOR]

Simple modifications of our novel ligand (Xing-Phos) were presented in this work, and a series of aromatic tertiary amide derived non-biaryl atropisomers were successfully synthesized in good yields. In addition, it was found that the multifunctional aromatic tertiary amide derived non-biaryl atropisomers exhibited an excellent endo -selectivity in the silver-catalyzed [3+2]-cycloaddition of azomethine ylides with N -aromatic maleimide. And especially, good to high levels of enantioselectivity (up to 98% ee ) was obtained with a wide range of substrates in the presence of syn -( R , R S )- 2a (Xing-Phos). Furthermore, on the basis of the experimental data, it was demonstrated that a trace amount of water play an important role in the enhancement of enantioselectivity. [ABSTRACT FROM AUTHOR]

Cyclization of silylenolether-ynesulfonamides proceeds at ambient temperature under mild reaction conditions under silver catalysis. Bridged compounds were obtained exclusively through 7 -exo-dig reactions. The protocol is applicable to a wide range of substrates, thus leading to azabicyclic frameworks. [ABSTRACT FROM AUTHOR]

In this study, the mechanism of AgAAC reaction has been studied by quantum mechanical calculations to gain insights into this promising reaction and the first successful application of a Ag catalyst alone in AAC. Elucidating the reaction mechanism will enable more control over the synthesis and help to obtain tailor made products in good yields without copper. The feasibility of the experimentally proposed reaction mechanism was investigated by modelling the profound intermediates and the transition state structures connecting them. The DFT calculations with the wB97XD functional with MWB28 effective core potential and 6-31+G* basis set combination herein show that once the silver acetylide structure forms, triazole synthesis via the experimentally proposed cycloaddition is a facile reaction in terms of energetics. The number of metal atoms involved in a click reaction is one of the main questions considered in mechanistic studies. In AgAAC reaction, comparison of mononuclear and binuclear paths shows that the barrier for binuclear cases is lower than that of mononuclear cases. [ABSTRACT FROM AUTHOR]

A silver-catalyzed cascade cyclization of cinnamamides with diphenylphosphine oxide was developed, in which activation of the P-H bond and functionalization of the C(sp²)-H bond occurred. A direct method for the synthesis of 3,4-disubstituted dihydroquinolin-2(1H)-ones was developed. [ABSTRACT FROM AUTHOR]

A silver-catalyzed decarboxylative addition/aryl migration/desulfonylation of N-phenyl-N-(phenylsulfonyl)methacrylamide with primary, secondary, and tertiary carboxylic acids was described. The protocol provides an efficient approach for the synthesis of α-all-carbon quaternary stereocenters amides and isoquinolinediones. It was proposed that the radical generated from the silver-catalyzed decarboxylation was involved in the sequence reaction. [ABSTRACT FROM AUTHOR]

A stereoselective one-pot synthesis of spiropyrazolones through an organocatalytic asymmetric Michael addition and a formal Conia-ene reaction has been developed. Depending on the nitroalkene, the 5-exo-dig-cyclization could be achieved by silver-catalyzed alkyne activation or by oxidation of the intermediate enolate. The mechanistic pathways have been investigated using computational chemistry and mechanistic experiments. [ABSTRACT FROM AUTHOR]

Unprecedented domino oxidative cyclization reactions of unprotected 2-alkynylanilines to give functionalized 4H-benzo[d][1,3]oxazin-4-one or benzisoxazole derivatives in moderate to good yields are achieved by silver vs. gold selective catalysis. The search for the optimal reaction conditions revealed the divergent catalytic activity of NaAuCl4·H2O and AgNO3. [ABSTRACT FROM AUTHOR]

A silver nanoparticle composite based on modified polyallylamine has been synthesized by a simple chemical route and its catalytic activity has been tested for alkyne–azide cycloaddition reaction. This silver nanocomposite shows an excellent catalytic activity at 80 °C for the synthesis of 1,4-disubstituted 1,2,3-triazole by alkyne–azide cycloaddition. The solid silver nanocomposite catalyst was characterized by transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffractometry and thermogravimetric analysis. The developed catalyst is stable in air, easy to prepare and can be recovered easily and reused ten times without a significant decrease in activity. [ABSTRACT FROM AUTHOR]