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An efficient route for the chemoselective deoxygenation of benzylphenyl sulfones to the corresponding sulfides has been developed using a mixture of 1,2-bis(diphenylphosphino)ethane(dppe) and NBS as an effective promoter. This is the first development on the deoxygenation of diverse benzylphenyl sulfones under metal-free conditions. The mild reaction conditions, formation of the water soluble by-product and tolerance of a wide range of functional groups promote its broad applications in organic synthesis. [ABSTRACT FROM AUTHOR]

A transition metal‐free synthesis of alkylidene dihydroisobenzofurans from the ortho‐alkynyl allylic alcohols is reported herein. Notably, a simple base tBuOK is utilized for the 5‐exo‐dig cyclization and double bond isomerization of ortho‐alkynyl allylic alcohols to furnish alkylidene dihydrobenzofurans with Z‐stereoselectivity under shorter reaction times. In addition, the geometry of the double bonds was confirmed by 1D Selective Gradient NOESY and 2D NMR (NOESY) analysis. Furthermore, the effectuality of the ortho‐alkynyl allylic alcohols has been shown by extending to the one‐pot synthesis of indanones via aqueous acid‐mediated hydrolysis (ring‐opening) of in‐situ formed dihydroisobenzofurans followed by intramolecular condensation reaction under acidic conditions [ABSTRACT FROM AUTHOR]

The Rutaceae family is one of the most studied plant families due to the large number of alkaloids isolated from them with outstanding biological properties, among them the quinoline-based alkaloids Graveoline 1 and Dubamine 2. The most common methods for the synthesis of alkaloids 1 and 2 and their derivatives involves cycloaddition reactions or metal-catalyzed coupling processes but with some limitations in scope and functionalization of the quinoline moiety. As a continuation of our current studies on the synthesis and chemical transformation of 2-aminochalcones, we are reporting here an efficient metal-free approach for the total synthesis of alkaloids 1 and 2 along with their analogues with structural diversity, through a two-step sequence involving intramolecular cyclization, oxidation/aromatization, N-methylation and oxidative C-C bond processes, starting from dihydroquinolin-4-ones as common precursors for the construction of the structures of both classes of alkaloids. [ABSTRACT FROM AUTHOR]

SP 1 sp H NMR (400 MHz, CDCl SB 3 sb ): = 7.48-7.20 (m, 2 H), 7.08-7.04 (m, 2 H), 4.38-4.35 (m, 1 H), 3.53-3.49 (m, 1 H), 3.44-3.41 (m, 1 H), 3.29 (s, 3 H). SP 1 sp H NMR (400 MHz, CDCl SB 3 sb ): = 7.34-7.24 (m, 6 H), 7.10-7.05 (m, 2 H), 4.24 (d, I J i = 10.80 Hz, 1 H), 4.16 (d, I J i = 11.20 Hz, 1 H), 3.17 (s, 3 H). SP 1 sp H NMR (400 MHz, CDCl SB 3 sb ): = 7.41-7.22 (m, 5 H), 4.41-4.37 (m, 1 H), 3.57-3.52 (m, 1 H), 3.50-3.45 (m, 1 H), 3.32 (d, I J i = 2.40 Hz, 3 H). SP 1 sp H NMR (400 MHz, CDCl SB 3 sb ): = 7.41-7.39 (m, 4 H), 7.34 (t, I J i = 7.20 Hz, 4 H), 7.30-7.24 (m, 2 H), 4.28 (s, 2 H), 3.20 (s, 3 H). [Extracted from the article]

The Rutaceae family is one of the most studied plant families due to the large number of alkaloids isolated from them with outstanding biological properties, among them the quinoline-based alkaloids Graveoline 1 and Dubamine 2. The most common methods for the synthesis of alkaloids 1 and 2 and their derivatives involves cycloaddition reactions or metal-catalyzed coupling processes but with some limitations in scope and functionalization of the quinoline moiety. As a continuation of our current studies on the synthesis and chemical transformation of 2-aminochalcones, we are reporting here an efficient metal-free approach for the total synthesis of alkaloids 1 and 2 along with their analogues with structural diversity, through a two-step sequence involving intramolecular cyclization, oxidation/aromatization, N-methylation and oxidative C-C bond processes, starting from dihydroquinolin-4-ones as common precursors for the construction of the structures of both classes of alkaloids.

In recent years, the importance of "environmentally friendly manufacturing" has been increasing toward the establishment of a resource-recycling society. In organic synthesis, as well, it is becoming increasingly important to develop new synthetic strategies with resource conservation and the recycling of elemental resources in mind, rather than just only synthesis. Many studies on the construction of frameworks of functional molecules using ionic reactions and transition-metal-catalyzed reactions have been reported, but most of them have focused on the formation of carbon–carbon bonds. However, it is essential to introduce appropriate functional groups at appropriate positions in molecules in order for the molecules to express their functions, and furthermore, the highly selective preparation of multiple functional groups is considered important for the creation of new functional molecules. In this review, we focus on radical reactions with high functional group selectivity and overview the recent progress in practical methods for the simultaneous introduction of multiple functional groups and propose future synthetic strategies that emphasize the recycling of elemental resources and environmental friendliness. [ABSTRACT FROM AUTHOR]

A convenient and practical method for the synthesis of unsymmetrical triarylmethanes was demonstrated through a one-pot three-component double Friedel–Crafts reaction of various aliphatic, aromatic, or heteroaromatic aldehydes with N , N -dialkylanilines and indoles by using a Brønsted acidic ionic liquid as the catalyst. This method was successfully applied under metal- and solvent-free conditions at 80 °C, affording the corresponding unsymmetrical triarylmethane products in moderate to high yields from a broad range of substrates. In addition, the mechanism of this reaction was studied by quantitative NMR analysis. [ABSTRACT FROM AUTHOR]

In recent years, the importance of “environmentally friendly manufacturing” has been increasing toward the establishment of a resource-recycling society. In organic synthesis, as well, it is becoming increasingly important to develop new synthetic strategies with resource conservation and the recycling of elemental resources in mind, rather than just only synthesis. Many studies on the construction of frameworks of functional molecules using ionic reactions and transition-metal-catalyzed reactions have been reported, but most of them have focused on the formation of carbon–carbon bonds. However, it is essential to introduce appropriate functional groups at appropriate positions in molecules in order for the molecules to express their functions, and furthermore, the highly selective preparation of multiple functional groups is considered important for the creation of new functional molecules. In this review, we focus on radical reactions with high functional group selectivity and overview the recent progress in practical methods for the simultaneous introduction of multiple functional groups and propose future synthetic strategies that emphasize the recycling of elemental resources and environmental friendliness.

KOtBu-BF3.OEt2 mediated synthesis of quinazolin-4(3H)-ones from 2-substituted amides with nitriles and aldehydes have been developed. In this protocol, a variety of nitriles as well as aldehydes react with 2-substituted benzamides to corresponding quinazolin-4(3H)-ones products in good to moderate yields, via the cleavage of C-X and C-N bonds and the formation of double C-N bonds simultaneously, in presence of potassium tert-butoxide. [ABSTRACT FROM AUTHOR]

An efficient synthesis of methoxy-substituted thioxanthylium salts has been developed. The reaction of diaryl sulfides with benzoyl chlorides in the presence of TfOH smoothly proceeded to give the desired thioxanthylium salts in good yields. In their UV–vis spectra, the maximum absorption wavelengths of methoxy-functionalized thioxanthylium salts were observed at around 460 nm, which show a drastic red shift compared to the parent thioxanthylium salts. The present reaction provides a versatile access to functionalized thioxanthylium salts, and therefore it constitutes a promising tool for the synthesis of biologically and photochemically active molecules.

The first direct C(sp3)−H bond sulfonylation and sulfuration reactions of isoquinoline‐1,3‐(2H,4H)‐diones have been developed under transition‐metal‐free conditions. Using air as the sole oxidant, the C‐4 sulfonylated products of isoquinolones were synthesized using sulfinates as the sulfonating agents and NaI as an iodine source in AcOH/DMSO. The sulfuration reaction was realized for the first time using disulfides as sulfurating partners in a t‐BuOK/DMF catalytic system. Both procedures undergo a free radical reaction process with the advantages of high atom economy, green reaction conditions, readily accessible materials and broad substrate scope. [ABSTRACT FROM AUTHOR]

Terminal alkynes were readily obtained via the reaction of alkynoic acids with N,N,N',N'‐teramethylethylenediamine (TMEDA) in DMSO at 65 °C for 12 h. This method gave good yields and showed high functional group tolerance. In addition, deuterated terminal alkynes were formed in good yields when alkynoic acids were treated with D2O prior to the reaction with TMEDA. [ABSTRACT FROM AUTHOR]

Nitrogen‐containing compounds widely exist in pharmaceuticals and multifunctional materials. Thus, the development of C−N bond formation reactions is of great importance in synthetic chemistry. Since 2014, obvious progress has been made in the construction of C−N bonds via metal‐free radical C(sp3)−H functionalization, which is one of the major protocols due to its high reaction activity and mild conditions. To the best of our knowledge, there are still no exclusive reviews about the formation of C−N bonds through metal‐free radical C(sp3)−H functionalization. This review aims to highlight the recent advances in this area since 2014, according to the type of the nitrogen source (amines, amides, sulfonamides, azoles, azides and other nitrogen sources). The paper is focused on discussions about the reaction mechanisms and selected examples of substrates have also been listed. [ABSTRACT FROM AUTHOR]

A facile and general synthesis of 2,4,6‐triaryl pyrimidines has been developed. It involves a one‐pot [2+1+1+1+1] pseudo five‐component annulation of one methyl ketone, two aldehydes and two NH4OAc catalyzed by TfOH. One C−C and four C−N bonds are formed during the oxidative annulation process. The reaction shows good tolerance of many important functional groups in air and produces only water as the coproduct, making this methodology a highly versatile alternative to the existing methods for structuring pyrimidine framework. [ABSTRACT FROM AUTHOR]

• K 2 S 2 O 8 catalysed oxidative coupling of o -phenylene diamines and primary alcohols for the synthesis of benzimidazoles. • Light emitting properties of benzimidazoles were studied. • The absorption and emission spectra of compounds were experimentally and theoretically analysed. We report the K 2 S 2 O 8 catalyzed oxidative coupling of 1,2-diaminobenzenes and primary alcohols for the synthesis of benzimidazoles under metal-free conditions by utilizing oxygen from air as terminal oxidant and water in reaction medium. Also, the challenging aliphatic alcohols showed good performance in synthesis of benzimidazoles. We also carried out a detailed exploration of the mechanism. The metal-free conditions, commercially available oxidant and good functional-group tolerance are the advantages of the present strategy. Further, we have studied the light emitting properties of benzimidazoles. The absorption and emission spectra's of the compounds 5a and 6m were experimentally and computationally analysed. Also, HOMO/LUMO distributions of compound 5a and 6m were elucidated theoretically. [Display omitted] [ABSTRACT FROM AUTHOR]

A novel metal‐free synthesis of 3,3‐disubstituted benzofuran‐2‐(3H)‐ones through reacting α‐aryl‐α‐diazoacetates with triarylboranes is presented. Initially, triarylboranes were successfully investigated in α‐arylations of α‐diazoacetates, however in the presence of a heteroatom in the ortho position, the boron enolate intermediate undergoes an intramolecular rearrangement to form a quaternary center. The intermediate cyclizes to afford valuable 3,3‐disubstituted benzofuranones in good yields. [ABSTRACT FROM AUTHOR]

An environmentally friendly, inexpensive, carbocatalyst, graphene oxide (GO) promoted efficient, metal‐free transamidation of various carboxamides with aliphatic, cyclic, and aromatic amines is demonstrated. The protocol is equally applicable to phthalimide, urea, and thioamide determining its adaptability. The oxygenated functionalities such as carbonyl (−C=O), epoxy (−O−), carboxyl (−COOH) and hydroxyl (−OH), present on graphene oxide surface impart acidic properties to the catalyst. The graphene oxide being heterogeneous in nature, work efficiently under solvent‐free reaction conditions providing desired products in good to excellent yields. The one‐pot synthesis of 2,3‐Dihydro‐5H‐benzo[b]‐1,4‐thiazepin‐4‐one moiety by GO catalyzed Aza Michael addition followed by intramolecular transamidation is also described. A plausible reaction mechanistic pathway involving H‐bonding is discussed. The graphene oxide can be recycled and reused up to five cycles without much loss in catalytic activity. [ABSTRACT FROM AUTHOR]

A green and cost-effective Pummerer-type rearrangement between readily accessible carboxylic acids and DMSO has been achieved under metal-free conditions in satisfactory to excellent yields. The transformation for the synthesis of valuable methylthiomethyl esters is shown to be a convenient strategy for various (hetero)aromatic acids, α,β-unsaturated carboxylic acids and saturated alkyl carboxylic acids with good functional group tolerance. [ABSTRACT FROM AUTHOR]

Abstract: A metal‐free protocol for oxidative coupling of malonic esters with styrenes to form γ‐keto diesters has been developed. Key to the success of this process is the generation of malonyl radicals from unfunctionalized malonic esters under organo‐catalysis conditions with TBAI and TBHP. This process tolerates both terminal and internal olefins with diverse malonic esters. It provides a new green metal‐free alternative to traditional metal mediated process for generation of malonyl radicals and there by γ‐keto diesters. [ABSTRACT FROM AUTHOR]

An efficient Brönsted acid-surfactant-combined ionic liquid (BASILs) catalyzed cyclocondensation of 2-aminothiophenol with a variety of aldehydes in water is described. This protocol was successfully conducted under metal-free conditions at ambient temperature and produced 2-alkyl and 2-arylbenzothiazole products in high to excellent yields (up to 98%). The catalyst was reusable at least four times without significant loss of activity. [Display omitted] • Brönsted acid-surfactant-combined ionic liquid was used as reusable catalyst for the green synthesis of 2-alkyl and 2-arylbenzothiazoles. • The novel method was successfully achieved under water media at ambient temperature. • High and excellent yields of the desired products were obtained from a variety of aliphatic, aromatic and heteroaromatic aldehyde substrates. An efficient Brönsted acid-surfactant-combined ionic liquid (BASILs) catalyzed cyclocondensation of 2-aminothiophenol with a variety of aldehydes in water is described. This protocol was successfully conducted under metal-free conditions at ambient temperature and produced 2-alkyl and 2-arylbenzothiazole products in high to excellent yields (up to 98%). The catalyst was reusable at least four times without significant loss of activity. [ABSTRACT FROM AUTHOR]

A metal-free protocol for Minisci C–H alkylation of heteroarenes using alkyl peroxides as the alkylating reagents and internal oxidants simultaneously under promotion of Brønsted acid has been demonstrated. A series of alkyl substituted heteroarenes were readily prepared by the C–H alkylation in moderate to good yields. A possible pathway involving the addition of alkyl radical to heterocycle followed by rearomatization is described. [ABSTRACT FROM AUTHOR]

Abstract: A series of C3‐unsymmetric spirooxindoles were achieved by reaction of diphenylmalonamides with PhI(OAc)2 (PIDA) under metal‐free conditions. Control experiments suggest that the hypervalent iodine‐mediated reaction undergoes a cascade process involving an oxidative C−C bond formation preceeding an oxidative C−N bond formation. [ABSTRACT FROM AUTHOR]

Upon treatment with solely a hypervalent iodine reagent of phenyliodine(III) bis(trifluoroacetate) (PIFA), 3-(2-hydroxyphenyl)-3-oxo- N-phenyl propanamides and a series of its derivatives were conveniently converted to a class of undocumented spirofurooxindoles under mild conditions. Control experiments provided evidence that this spirocyclization process encompassed a cascade oxidative reactions involving the formation of a C-O bond prior to that of C-C bond. [ABSTRACT FROM AUTHOR]

2,2,2-Trichloroacetophenone derivatives were synthesized via decarboxylative trichlorination from arylpropiolic acids and trichloroisocyanuric acid (TCCA). The reaction was performed in the presence of water at room temperature, and the desired products were obtained in good yields. The reaction showed good functional group tolerance towards halide, cyano, nitro, ketone, ester and aldehyde groups. In addition, the 2,2,2-trichloroacetophenone derivatives were readily transformed into esters, amides, and hydrazides. Based on experiments with H218O (water-18O), we proposed a cationic reaction pathway as the mechanism and suggested two different pathways for producing aryl- and alkyl-substituted propiolic acids. [ABSTRACT FROM AUTHOR]

An iodine-triggered dioxygen activation in oxysulfonylation reactions of unactivated olefins using sulfonyl hydrazides and iodine as catalyst is reported here. In one pot, near quantitative syntheses of β-hydroxysulfones were achieved at 70 °C, within 7 h, in acetonitrile and under aerobic conditions. A plausible mechanism is established by radical trapping and 18O labelling experiments for the operationally simple, efficient and economically viable transformation. The direct activation of aerial oxygen under metal-free and mild conditions is proposed for the oxysulfonylation of olefins. [ABSTRACT FROM AUTHOR]

A new metal-free oxidative cascade methylation/cyclization of benzene-linked 1,7-enynes to construct methylated polyheterocyclic scaffold skeletons is described. In this transformation, three new C-C bonds and two new rings are formed. Notably, di- tert-butyl peroxide (DTBP) acts not only as a radical initiator but also as an efficient methyl source. [ABSTRACT FROM AUTHOR]

A metal-free, PhI(OCOCF 3 ) 2 -mediated C N bond forming reaction was developed between quinolines and nitrogen source, affording a facile route for the construction of 2-aminoquinolines via a nitrogen-centered radical process. This reaction represents a significant addition to the limited number of existing transition metal-catalyzed processes for the C-2 amination of quinolines and will find practical application in the synthesis of nitrogen-functionalized quinolines. [ABSTRACT FROM AUTHOR]

A facile and metal-free access to pyrazoles from 1,3-diarylpropenes and hydrazines via multiple inter-/intramolecular C-H aminations was described. Under the neutral and mild 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) oxidative conditions, various disubstituted pyrazoles were synthesized in moderate to excellent yields. This method provides a pot- and step-economic strategy for the construction of pyrazoles, especially those for drug discovery. [ABSTRACT FROM AUTHOR]

This work describes the use of cheap, safe, and easy-to-handle hydrosilatrane as the reductant in direct reductive amination reactions. This efficient method enables a facile, metal-free access to secondary and tertiary amines from a wide range of aldehydes and ketones, with the synthesis of tertiary amines requiring no additives at all. This reaction demonstrates excellent functional group tolerance, chemoselectivity, and scalability. [ABSTRACT FROM AUTHOR]

A new protocol has been developed for the formation of C−Se and C−S bonds by the direct selenosulfonylation of alkenes. This protocol is operationally simplistic, has a wide substrate scope, uses readily available seleno and sulfonyl sources, and is amenable to gram-scale synthesis. This reaction represents a significant addition to the limited number of reactions available for the intermolecular selenide difunctionalization of alkenes and would be useful for the synthesis of sulfur- and selenium-containing molecules [ABSTRACT FROM AUTHOR]

Heteroaromatic sulfoxides are a frequent structural motif in natural products, drugs, catalysts, and materials. We report a metal-free visible-light-accelerated synthesis of heteroaromatic sulfoxides from sulfinamides and peroxodisulfate. The reaction proceeds at room temperature with blue-light irradiation and allows the C−H sulfinylation of electron-rich heteroarenes, such as pyrroles and indoles. An electrophilic aromatic substitution mechanism is proposed based on the substrate scope, substitution selectivity, and competition experiments with different nucleophiles. [ABSTRACT FROM AUTHOR]

Graphite oxide as a heterogeneous and recyclable solid acid catalyzed a simple and efficient method for the synthesis of β-amino alcohols by ring opening of epoxides with amines. This method is effective with various aromatic and aliphatic amines under solvent-free conditions. The corresponding β-amino alcohols are obtained in high yields (56%-95%) and short reaction times (15-30 min) with high regio- and chemoselectivity under metal-free conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ph 3 P·I 2 was used to mediate the deprotection of aryl alkyl ethers. • The method possesses comparatively broad substrate scope. • Metal-free and neutral reaction conditions were used. • A variety of aryl alkyl ethers can be highly efficiently deprotected. A highly efficient method for the deprotection of aryl alkyl ethers under metal-free and neutral conditions was developed by iodotriphenylphosphonium iodide [Ph 3 P+I]I− formed in situ through the reaction of equimolar PPh 3 and I 2. A variety of aryl alkyl ethers including aryl methyl/allyl/benzyl/ethyl/ n -propyl/ i -propyl/ n -butyl ethers can all be highly efficiently deprotected to release the corresponding phenols in good to excellent yields. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ph 3 P·I 2 was used to promote the demethylaromatization of cyclohexadienones. • The single one-step conversion of cyclohexadienones into phenols was developed. • The method possesses comparatively broad substrate scope. • Metal-free and neutral reaction conditions were used. A highly efficient and metal-free demethylation and concomitant aromatization of cyclohexadienones using iodotriphenylphosphonium iodide was developed. A variety of steroidal and non-steroidal substrates smoothly underwent demethylaromatization reaction generating the corresponding phenolic products in good yields. This approach exhibits broad functional group tolerance. An ionic mechanism of synergistic action was proposed. This method shows potential industrial value in the one-step transformation of 1,4-androstadiene-3,17-dione into 3-hydroxy-1,3,5(10)-estratrien-17-one which serves as a key precursor to a series of steroidal contraceptives. [ABSTRACT FROM AUTHOR]

A metal-free synthesis of biologically important benzazepines is achieved through a single synthetic operation involving an oxidative C-H bond functionalization and ring expansion with diazomethanes as key reagent. This represents a new, strong methodology for the straightforward construction of the seven-ring N-heterocyclic structures under mild conditions using a 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) oxoammonium salt as oxidant. Moderate to good yields are achieved from simple, readily available tetrahydroisoquinolines, and this methodology has been further successfully applied for the synthesis of the 3-benzazepine drug Lorcaserin. A possible mechanistic pathway for the ring expansion step, comprising the extrusion of nitrogen in a concerted asynchronic process, is proposed based on both mechanistic proof and density function theory (DFT) calculations. [ABSTRACT FROM AUTHOR]

Seven ferrocenyl-based unsymmetrical azines 3a – 3f and 5a were synthesized under metal-free conditions in good yields. Ferrocene-based unsymmetrical azines 3f and 5a have shown to be excellent multichannel chemosensors for Hg 2+ and Cu 2+ ions in aqueous environment. The color of the solution containing chemosensor 3f changed from yellow to colorless, upon the addition of Hg 2+ and Cu 2+ ions. Quantification of the absorption titration analysis shows that the detection limit was 6.77 × 10 −7 M for 3f -Cu 2+ and 7.19 × 10 −7 M for 3f -Hg 2+ , respectively. For 5a , the detection limit can reach 1.29 × 10 −7 M and 2.40 × 10 −7 M for Cu 2+ and Hg 2+ , respectively. Moreover, 1-substituted ferrocene-based unsymmetrical azines 3a–3e with electron-rich, electron-neutral, and electron-deficient aryl groups have significant influence on the sensitivity. [ABSTRACT FROM AUTHOR]

We disclose here the first iodine/ tert-butyl hydroperoxide (I2/TBHP)-mediated benzylic C-H sulfonylation of phenol derivatives. This new methodology provides an economic, operationally simple and metal-free approach toward C( sp3)-S bond formation with medium to excellent yields at room temperature. Moreover, a novel sulfonylative and peroxidative bifunctionalization of phenol derivatives was also achieved by changing the amount of the oxidant. The reaction mechanism is exemplified via a radical pathway. [ABSTRACT FROM AUTHOR]

We have achieved a rare-metal-free photo-aerobic intramolecular dehydrogenative coupling reaction from two C-H bonds of indole with malonate. This catalytic system proceeded at room temperature under visible light irradiation with oxygen in the air as a terminal oxidant, and the cyclization products were obtained in good to excellent yields. [ABSTRACT FROM AUTHOR]

A novel, efficient, and metal-free dual C–O bond formation reaction for the synthesis of carboxylic anhydrides from aryl aldehydes via cross-dehydrogenative coupling is described. Heating a mixture of aromatic aldehydes and an aqueous solution of tert -butyl hydroperoxide as oxidant in the presence of catalytic n Bu 4 PBr in chlorobenzene at 80 °C for 3 h afforded the corresponding carboxylic anhydrides in good to excellent yields. [ABSTRACT FROM AUTHOR]

Herein a practical and efficient protocol for preparing a range of aminoisoquinolines is reported. Various aminoisoquinolines were prepared in moderate to good yields from the corresponding 2-methylbenzonitriles and benzonitriles upon treatment with potassium tert-butoxide. [ABSTRACT FROM AUTHOR]

A transition metal-free direct arylation of 2-substituted cyanoacetates with diaryliodonium salts was developed. With this approach, a wide range of α-tolunitrile derivatives has been synthesized in good to excellent yields of 45-92%. Furthermore, the practicability of this approach is further manifested in the synthesis of a related bioactive agent of glutarimide. [ABSTRACT FROM AUTHOR]

We report here the first general method for the geminal diamination and an intermolecular metal-free, geminal aminooxygenation of vinylarenes using hypervalent iodine reagent. A new m -CPBA mediated geminal aminooxygenation is also reported. A novel reagent-switch for the control of migrating group by controlling the two independent geminal addition paths is developed. Deuterium labelling studies and the control studies have provided unambiguous evidences for the phenyl migration and hydride migration in the oxidative geminal difunctionalization process mediated by PhI(OCOCF 3 ) 2 and m -CPBA, respectively through a semi-pinacol rearrangement. [ABSTRACT FROM AUTHOR]

A simple and an efficient multicomponent domino protocol is developed for the synthesis of 2-iminothiazolines starting from simple and readily available arylacetylenes, amines, and phenyl isothiocya-nates under base-free conditions. The present method involves oxy-iodination of the arylacetylenes with ammonium iodide and hydrogen peroxide, followed by cyclization processes. A number of diversely functionalized 2-iminothiazolines are synthesized in good to excellent yields. [ABSTRACT FROM AUTHOR]

The cross-coupling reaction between Nhydroxyphthalimide and various benzylic and allylic hydrocarbons was realized through an organocatalytic radical-mediated process involving C(sp3)-O bond formation using tert-butyl hydroperoxide (t- BuOOH) as an oxidant and tetra-n-butylammonium iodide [(n-Bu]4NI] as a catalyst, during which the phthalimide N-oxyl (PINO) radical and benzylic and allylic radicals were generated in situ and underwent the selective radical/radical cross-coupling reaction. This novel method provides a convenient metal-free approach to the synthesis of O-alkylated hydroxy imides under mild reaction conditions. [ABSTRACT FROM AUTHOR]

Heterocyclic compounds are indispensable structures that have widespread occurrence in nature and exhibit fascinating biological and pharmaceutical activities. Particularly, quinolinones and isoquinolinones are a class of N -heterocyclic carbonyl compounds with numerous biological properties such as anti-malarial, anti-cancer, anti-tumor, and herbicidal activities Some of the representative examples of natural products possessing quinolinone core are 3- O -Methylviridicatin, Brexipiprazole, Waltherione C, Waltherione D, Japonine, and Leiokinine A. Similarly, the natural products containing isoquinolinone as the core structure of Thalflavine, Corydaline, Doryanine, Oxyavicine, Oxynitidine, Ruprechstyril, (+)-Pancratistatin and (+)-Pilcamine. Due to the vast biological and pharmacological significance of N -heterocyclic carbonyl compounds, chemists have become attracted to developing new synthetic approaches. As a result, numerous reports have been disclosed in the recent past. Therefore, this review emphasizes the recent developments in quinolinones synthesis mainly through solvent-free conditions and electrochemically and photochemically driven methods. Further, comprised of some recently developed protocols for synthesizing isoquinolinones largely under C–H activation conditions driven transition metal catalysts (e.g., Co, Pd & Rh, etc.). [Display omitted] [ABSTRACT FROM AUTHOR]

A mild and efficient cascade synthesis of 1,5-diketones from readily available N, N-dicyclohexylmethylamine, 1,3-dicarbonyl compounds, and trifluoromethyl β-diketones has been developed. This cascade reaction occurs via an oxidation/Mannich reaction/Cope elimination/Michael addition/retro-Claisen reaction sequence, and provides multiple CC bond formations in one pot. In addition, exquisite chemoselectivity is achieved in the reaction between 1,3-dicarbonyl compounds and trifluoromethyl β-diketones. [ABSTRACT FROM AUTHOR]

A robust synthetic method for a variety of pyridoisoindoles from pyridinylarylacetates has been developed through diazotization using 4-methylbenzenesulfonyl azide and 1,8-diazabicyclo[5.4.0]undec-7-ene followed by intramolecular cyclization via elimination of a nitrogen molecule under copper(II) trifluoromethanesulfonate-catalyzed conditions in a one-pot process. The intramolecular cyclization also took place efficiently with diazo substrates to produce pyridoisoindoles in good to excellent yields under metal-free conditions or catalytic conditions [1.0 mol% copper(II) trifluoromethanesulfonate, 25 °C]. [ABSTRACT FROM AUTHOR]

Visible light and eosin Y catalyze the synthesis of vinyl sulfones from aryl sulfinates and alkenes by a photoredox process. The reaction scope is broad in aryl sulfinates and alkenes and the general and simple procedure provides a metal-free alternative for the synthesis of synthetically valuable vinyl sulfones. [ABSTRACT FROM AUTHOR]