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Visible-light-mediated reactions have recently emerged as a powerful strategy for the synthesis of diverse organic molecules under mild reaction conditions. Usually, the reactions are performed at room temperature and thus sensitive functional groups remain unaffected. Thus, this protocol has received intense interest from academia as well as industries. The heterocycles, in general, are of much interest because of their biological activities and application in therapeutics. The Oxygen- and Sulfur-containing heterocyclic compounds have recently attracted attention as these compounds showed promising activities as anti-cancer drugs, antibiotics, antifungal and anti-inflammatory agents among other applications. The synthesis of this class of compounds by efficient and greener routes has become an important target. This review highlights the various procedures for the synthesis of these compounds and their derivatives under visible light-induced reactions. The green aspects and mechanism of each procedure have been discussed., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

The solvent-free mechanochemical reactions under ball milling have emerged as a promising alternative to traditional solution-based chemistry. This approach not only eliminates the necessity for large quantities of solvents and minimizes waste production, but it also facilitates a unique reaction environment that enables strategies, reactions, and compound syntheses that are typically unattainable in solution. This solvent-less synthetic strategy under ball-milling has been well employed in synthetic organic chemistry in accessing various potential organic molecules including pharmaceutically important molecules and pharmaceuticals or drug-molecules. This review highlights the potential of ball milling in the synthesis of pharmaceutically important classes of molecules without using any solvent (solvent-free conditions).

A series of α-cycloamine substituted 2,2'-bipyridines 3ae'-3ce' was obtained via the one-pot approach based on ipso-substitution of a cyano-group in 1,2,4-triazines, followed by aza-Diels-Alder reaction in good yields. Photophysical properties, including fluorosolvatochromism, were studied for 3ae'-3ce' and were compared with α-unsubstituted 2,2'-bipyridines. In addition, dipole moments differences in ground and excited states were calculated by both Lippert-Mataga equation and DFT studies and were compared to each other. The correlation between the size of cycloamine unit and the dipole moments differences value (based on Lippert-Mataga equation) was observed. In addition charge transfer indices (D CT , Λ, H and t) were calculated to demonstrate influence of molecular structure on the intramolecular charge transfer degree., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Polyureas (PUs) have already found wide practical applications, and various methods of their synthesis have been reported. In this manuscript, we wished to report the very first mechanochemical approach towards aromatic PUs via reactions between isomeric 2,2'-, 3,3'-, and 4,4'-diaminobiphenyls and triphosgene under solvent-free conditions following ball-milling. By using this synthetic approach, both PUs and azomethine-capped Pus were obtained. The fluorescence response of the above-mentioned PUs towards various anions in solutions were studied and selective fluorescence responses towards the hydroxyl and fluoride anions were observed.

Methods for the remote detection of warfare agents and explosives have been in high demand in recent times. Among the several detection methods, fluorescence methods appear to be more convenient due to their low cost, simple operation, fast response time, and naked-eye-visible sensory response. For fluorescence methods, a large variety of fluorescent materials, such as small-molecule-based fluorophores, aggregation-induced emission fluorophores/materials, and supramolecular systems, have been reported in the literature. Among them, fluorescent (bio)polymers/(bio)polymer-based materials have gained wide attention due to their excellent mechanical properties and sensory performance, their ability to recognize explosives via different sensing mechanisms and their combinations, and, finally, the so-called amplification of the sensory response. This review provides the most up-to-date data on the utilization of polymers and polymer-based materials for the detection of nitroaromatic compounds (NACs)/nitro-explosives (NEs) in the last decade. The literature data have been arranged depending on the polymer type and/or sensory mechanism.

1,4-Bis(5-phenyl-2-oxazolyl)benzene (POPOP) is a common scintillation fluorescent laser dye. In this manuscript, the synthesis of 2-Ar-5-(4-(4-Ar'-1 H -1,2,3-triazol-1-yl)phenyl)-1,3,4-oxadiazoles (Ar, Ar' = Ph, naphtalenyl-2, pyrenyl-1, triphenilenyl-2), as PAH-based aza -analogues of POPOP, by means of Cu-catalyzed click reaction between 2-(4-azidophenyl)-5-Ar-1,3,4-oxadiazole and terminal ethynyl-substituted PAHs is reported. An investigation of the photophysical properties of the obtained products was carried out, and their sensory response to nitroanalytes was evaluated. In the case of pyrenyl-1-substituted aza -POPOP, dramatic fluorescence quenching by nitroanalytes was observed.

Mechanochemically induced methods are commonly used for the depolymerization of polymers, including plastic and agricultural wastes. So far, these methods have rarely been used for polymer synthesis. Compared to conventional polymerization in solutions, mechanochemical polymerization offers numerous advantages such as less or no solvent consumption, the accessibility of novel structures, the inclusion of co-polymers and post-modified polymers, and, most importantly, the avoidance of problems posed by low monomer/oligomer solubility and fast precipitation during polymerization. Consequently, the development of new functional polymers and materials, including those based on mechanochemically synthesized polymers, has drawn much interest, particularly from the perspective of green chemistry. In this review, we tried to highlight the most representative examples of transition-metal (TM)-free and TM-catalyzed mechanosynthesis of some functional polymers, such as semiconductive polymers, porous polymeric materials, sensory materials, materials for photovoltaics, etc.

Since their discovery in 2008 by N. Ogoshi and co-authors, pillararenes (PAs) have become popular hosts for molecular recognition and supramolecular chemistry, as well as other practical applications. The most useful property of these fascinating macrocycles is their ability to accommodate reversibly guest molecules of various kinds, including drugs or drug-like molecules, in their highly ordered rigid cavity. The last two features of pillararenes are widely used in various pillararene-based molecular devices and machines, stimuli-responsive supramolecular/host-guest systems, porous/nonporous materials, organic-inorganic hybrid systems, catalysis, and, finally, drug delivery systems. In this review, the most representative and important results on using pillararenes for drug delivery systems for the last decade are presented.

In the last few decades, ball-milling has received tremendous attention as a "green tool" for conducting various challenging organic transformations under transition-metal-free and solvent-free conditions. Organosulfur and related heterocycles are ubiquitous in numerous biologically active molecules with potential applications, and those molecules could be synthesized from readily available starting materials under mechanochemical conditions without using any hazardous chemical or solvent. This synopsis highlights the green strategies developed in recent times to synthesize organosulfur and related heterocycles under ball-milling conditions.

Bicyclic arenyl selenides are of much importance because of their pharmaceutical applications. A simple method for their synthesis has been developed by a reaction of 2-naphthol and styrenyl selenocyanate/diaryl diselenide in the presence of a base at room temperature. The selenation occurs exclusively at the 1-position of 2-naphthol unit. The reactions are relatively fast (2-4 h) and high yielding. A library of substituted naphthyl styrenyl and naphthyl aryl selenides are obtained by this procedure., Competing Interests: The authors declare no competing financial interest.

Diaryl ketones are of much importance in organic synthesis as versatile intermediates and in industry for their useful properties. A mild and efficient palladium-catalyzed traditional ligand-free decarboxylative coupling of aryl α-keto carboxylic acid with aryl diazonium fluoroborate has been developed. A series of unsymmetrical diaryl ketones has been synthesized in moderate to good yields using this procedure. A radical pathway involving the acyl radical has been suggested.

An efficient method for the C(sp 2 ) amidation of 8-aminoquinoline benzamide by acyl azide in the presence of copper acetate has been achieved via C-H activation. Interestingly, the loading of copper acetate has a strong influence on the outcome of the reaction. The use of 1 equiv of copper acetate produces the corresponding aroyl amide, whereas the use of 2 equiv led to acetyl amide. A series of substituted benzoyl and acetyl amides has been obtained.

A cobalt-catalyzed selective remote C-4 alkylation of 8-aminoquinoline amides via C-H activation under irradiation with a CFL lamp in the presence of eosin Y at room temperature has been achieved. A series of pharmaceutically important C-4 quinoline amide-substituted ether derivatives has been obtained by this procedure. The C-4 functionalization of quinoline amides with inert ether is of much significance and was not reported earlier.

A convenient procedure has been developed for the synthesis of styrenyl selenocyanates and benzoselenophenes from readily available styrenyl bromides by reaction with potassium selenocyanate in the presence of iodine under specified conditions. A series of both compounds have been obtained by this procedure. The synthesis of styrenyl selenocyanates has not been previously reported, and thus this method is of much significance.

Efficient tandem ortho-C-H-amination/ipso-cyanation of iodoarenes was accomplished under a norbornene-mediated Pd-catalyzed process. A series of functionalized 2-aminobenzonitriles with much potential in the pharmaceutical industry were obtained by this protocol. This strategy was successfully employed for substitution with two cyano and four amino functionalities in an arene unit in one step under specified conditions.

A convenient and general protocol for oxidative arylation of vinyl arenes by aryl radicals generated in situ from arene diazonium fluoroborates promoted by ascorbic acid in air at room temperature has been developed in the absence of any additive and visible light irradiation. A series of diversely substituted 2-aryl acetophenones have been obtained in good yields by this procedure.

Cobalt(II)-catalyzed C(sp(2) )O cross-coupling between aryl/heteroaryl alcohols and vinyl/aryl halides in the presence of Cu(I) has been achieved under ligand-free conditions. In this reaction, copper plays a significant role in transmetalation rather than being directly involved in the CO coupling. This unique Co/Cu-dual catalyst system provides an easy access to a library of aryl-vinyl, heteroaryl-styryl, aryl-aryl, and heteroaryl-heteroaryl ethers in the absence of any ligand or additive., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

An efficient cross-coupling of alkynes with alkynyl and alkenyl halides catalysed by a Ni-Cu system without any ligand has been achieved. The reaction is suggested to proceed by Ni(0) catalysis assisted by Cu(I). A series of functionalised diaryl, aryl-alkyl, aryl-heteroaryl, diheteroaryl 1,3-di-ynes and en-ynes are obtained in high yields.

An efficient Csp-Csp cross-coupling of alkynyl bromide and pinacol ester of alkynyl boronic acid catalyzed by CuFe2O4 nanoparticles has been accomplished in dimethyl carbonate to produce unsymmetric 1,3-diynes. This protocol is also extended for the Csp-Csp2 coupling of alkynyl bromide and alkenyl boronic acid to provide conjugated 1,3-enynes. The aliphatic, aromatic, and heteroaromatic alkynes couple with various substituted alkynyl/alkenyl boronates/boronic acids by this procedure to furnish a library of 1,3-diynes and enynes in high yields. The catalyst was easily separated by an external magnet and recycled 10 times.

An efficient protocol for the synthesis of selenophenes and selanyl selenophenes has been achieved by a simple one-pot reaction of 1,3-dienyl bromides and 1,3-dienyl-gem-dibromides respectively with KSeCN catalyzed by CuO nanoparticles. Several aryl, alkenyl, heteroaryl, and alkyl substituted selenophenes were obtained with a broad array of functional group tolerance. This is found to be a general methodology for chalcogenophenes being effective for the synthesis of thiophenes too.

An efficient protocol for the Pd-catalyzed regiospecific ortho-nitration of (E)-azoarenes has been achieved for the first time using tBuONO as a nitrating agent under atmospheric oxygen. A series of both symmetrical and unsymmetrical azoarenes were nitrated efficiently by this procedure providing excellent chemo- and regioselectivity and compatibility with a broad array of functional groups., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The use of a new ZnO-supported palladium(0) nanoparticle catalyst for the cyanation of aryl halides using a relatively benign cyanide source, K4[Fe(CN)6], is described. This catalyst has been applied for the efficient cyanation of a variety of functionalized aryl bromides and activated aryl chlorides. This process circumvents the need for an additive and a ligand for the reaction and offers the advantages of high product yields, low catalyst loading (0.2 mol % Pd), and recyclability of the catalyst.

A novel strategy for the direct conversion of aryl- and heteroarylamines to selenides has been developed via diazotization of amines with tert-butyl nitrite in neutral medium followed by reaction with diaryl/diheteroaryl/dialkyl diselenides in one pot under photocatalysis at room temperature in the absence of any metal. This reaction is also applied for the synthesis of tellurides. The selenylation of heteroarylamine by this protocol is of much significance because of the difficulty in diazotization of these molecules by a standard diazotization method in acid medium.

A convenient and efficient protocol has been achieved for the cross-coupling of phenols and vinyl halides by a unique Ni/Cu catalytic system for the first time, where the reaction is catalyzed by Ni and Cu is involved in the transmetalation process. This procedure provides an easy access to a library of aryl-vinyl and aryl-styrenyl ethers.

A selective N-arylation of cyclic amides and amines in DMF and water, respectively, catalysed by Cu(II) /Al2 O3 has been achieved. This protocol has been employed for the synthesis of a library of arenes bearing a cyclic amide and an amine moiety at two ends, including a few scaffolds of therapeutic importance. The mechanism has been established based on detailed electron paramagnetic resonance (EPR) spectroscopy, X-ray photoelectron spectroscopy (XPS), UV diffuse reflectance spectroscopy (DRS) and inductively coupled plasma-mass spectrometry (ICP-MS) studies of the catalyst at different stages of the reaction. The Cu(II) /Al2 O3 catalyst was recovered and recycled for subsequent reactions., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A convenient, efficient, and general procedure for the synthesis of diaryl chalcogenides including sulfides, selenides and tellurides has been developed by the reaction of diazonium tetrafluoroborates and diaryl dichalcogenides on the surface of alumina under ball-milling without any solvent or metal. A wide range of functionalized diaryl chalcogenides are obtained in high purity by this procedure.

Alumina-supported Cu(II) efficiently catalyzes selenylation of aryl iodides and aryl bromides by diaryl, dialkyl, and diheteroaryl diselenides in water and PEG-600, respectively, leading to a general route toward synthesis of unsymmetrical diaryl, aryl-alkyl, aryl-heteroaryl, and diheteroaryl selenides. A sequential reaction of bromoiodobenzene with one diaryl/diheteroaryl/dialkyl diselenide in water and another diaryl/diheteroaryl/dialkyl diselenide in PEG-600 in the second step produces unsymmetrical diaryl, diheteroaryl, or aryl-alkyl bis-selanyl benzene. A library of functionalized organo mono- and bis-selenides, including a potent biologically active molecule and a couple of analogues of bioactive selenides, were obtained in high yields by this protocol. The reactions are chemoselective and high yielding. The Cu-Al2O3 catalyst is recycled for seven runs without any appreciable loss of activity.

Overproduction of nitric oxide (NO) by inducible nitric-oxide synthase (iNOS) has been etiologically linked to several inflammatory, immunological, and neurodegenerative diseases. As dimerization of NOS is required for its activity, several dimerization inhibitors, including pyrimidine imidazoles, are being evaluated for therapeutic inhibition of iNOS. However, the precise mechanism of their action is still unclear. Here, we examined the mechanism of iNOS inhibition by a pyrimidine imidazole core compound and its derivative (PID), having low cellular toxicity and high affinity for iNOS, using rapid stopped-flow kinetic, gel filtration, and spectrophotometric analysis. PID bound to iNOS heme to generate an irreversible PID-iNOS monomer complex that could not be converted to active dimers by tetrahydrobiopterin (H4B) and l-arginine (Arg). We utilized the iNOS oxygenase domain (iNOSoxy) and two monomeric mutants whose dimerization could be induced (K82AiNOSoxy) or not induced (D92AiNOSoxy) with H4B to elucidate the kinetics of PID binding to the iNOS monomer and dimer. We observed that the apparent PID affinity for the monomer was 11 times higher than the dimer. PID binding rate was also sensitive to H4B and Arg site occupancy. PID could also interact with nascent iNOS monomers in iNOS-synthesizing RAW cells, to prevent their post-translational dimerization, and it also caused irreversible monomerization of active iNOS dimers thereby accomplishing complete physiological inhibition of iNOS. Thus, our study establishes PID as a versatile iNOS inhibitor and therefore a potential in vivo tool for examining the causal role of iNOS in diseases associated with its overexpression as well as therapeutic control of such diseases.

An efficient Sonogashira coupling of terminal alkynes and styrenyl bromides has been achieved under the catalysis of hydroxyapatite-supported copper(I). The trans-styrenyl bromides produce the usual trans-enyne products, whereas the cis-styrenyl bromides lead to unsymmetric 1,3-diynes by the cross coupling of terminal alkyne and the alkyne generated from the cis-styrenyl bromide. A series of trans-enynes and unsymmetric 1,3-diynes have been synthesized by this protocol.

Highly selective reduction of nitroarenes has been achieved using iron metal nanoparticles in water at room temperature. A wide spectrum of reducible functionalities remained inert under the reaction conditions. During the reaction a change in shape of Fe nanoparticles was observed.

An efficient cyanation of styrenyl bromides by K(4)[Fe(CN)(6)] has been achieved under the catalysis of hydroxyapatite-supported copper(I) producing a variety of functionalized cinnamonitriles in high yields. The stereochemistry of the styrenyl double bond is preserved during the process providing the same stereoisomer of product.

The carbon-carbon and carbon-heteroatom bond formations constitute the backbone of organic synthesis and have been widely used in the synthesis of natural products and useful compounds. Because of growing environmental concern, more attention has been focussed on the development of greener methods. Copper is environment-friendly and comparatively inexpensive. Although the use of copper salts in catalysis has been known since the last century, this area of research has been less explored compared to other metals, such as palladium, magnesium, and zinc. This review highlights the general features of nanoparticles as catalysts with particular reference to copper and the recent developments in the copper(0) nanoparticle-catalyzed C(aryl)-C(aryl/alkynyl), C(aryl)-N, C(aryl)-O, C(aryl)-S, and C(aryl)-Se bond formations and related reactions. The mechanisms of the reactions have been outlined and discussed with respect to the active catalytic species and possible intermediates. The scope, limitations, and green aspects of the reactions have also been highlighted. The convenient methods of preparation of copper nanoparticles and their characterization are described., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Aryl azides undergo clean reduction by copper nanoparticles and ammonium formate in water. The surface hydrogen on copper nanoparticles is considered to be the active reducing species. A variety of functionalized aryl azides and aryl sulfonyl azides are reduced by this procedure to the corresponding amines with excellent chemoselectivity in high yields.

A fast and efficient phenylselenylation of allyl acetates by diphenyl diselenide and indium(I) bromide has been achieved in neat under the catalysis of Ru(acac)(3). The intermediate complex of diphenyl diselenide and indium has been isolated and identified as a polymeric pentacoordinated In(III) selenolate complex, [In(SePh)(3)](n).

An easily accessible catalyst, alumina-supported copper(II), efficiently catalyzes the ring opening of aziridines and epoxides followed by cyclization of the corresponding intermediate to produce a variety of functionalized 1,4-benzoxazines and 1,4-benzodioxanes, respectively, in one pot without any ligand in high yields. The ring cleavages of aziridines and epoxides are highly regioselective. The catalyst is inexpensive, non-air-sensitive, environmentally friendly, and recyclable. The function of the catalyst and the reaction pathway are postulated. This protocol is successfully utilized for the formation of three carbon-heteroatom bonds, namely, C-O, C-N, and C-S, in one pot.

Alumina-supported copper sulfate efficiently catalyzes electrophilic substitution in organoborane, organosilanes, and organostannanes by phenylselenium bromide providing a novel and efficient route to the synthesis of unsymmetrical diaryl and alkyl aryl selenides. A series of aryl, alkyl, and heteroaryl phenyl selenides were obtained in high yields. The catalyst is inexpensive, eco- and user-friendly, and recyclable. The mechanism involving Cu-assisted nucleophilic displacement of Br in PhSeBr by mild nucleophiles is described.

The protection of the environment from toxic materials is an area of increasing concern. This review describes selected chemical processes that use more environmentally friendly solvents and less toxic catalysts. For example, water, ionic liquids and supercritical fluids have demonstrated promising activity as alternative benign reaction media for various reactions. The advantages of neat reactions in the absence of any solvent and the use of fluorous compounds as phase-separable catalysts are also described.

Palladium nanoparticles, generated in situ from the reaction of palladium(II) chloride, have been demonstrated to be an efficient catalyst for C-N bond formation. A variety of aliphatic and aromatic amines have been allylated by substituted and unsubstituted allyl acetates in high yields by using palladium nanoparticles in the presence of a base without any ligand. The allylations are highly regio- and stereoselective.

A simple and efficient procedure for the synthesis of aryl- and vinyl-selenides has been developed by a copper nanoparticle catalysed reaction of aryl iodide/vinyl bromide with diphenyl diselenide in the presence of zinc in water. (E)-Vinyl bromides produce (E)-vinyl selenides stereoselectively, whereas (Z)-vinyl bromides provide mixtures of (E) and (Z) isomers. The catalyst was recycled.

The cross-coupling of allyl acetates and aryl and vinyl siloxanes proceeds readily by the catalysis of in situ generated palladium(0) nanoparticles. The reactions are stereoselective, and (E)-coupling products are obtained both from cis and trans allyl acetates. The coupling with vinyl siloxanes provides a novel protocol for the synthesis of 1,4-pentadienes.

In an unusual reaction of osmium(VIII) oxide with p-substituted aromatic amines (X-C(6)H(4)-NH(2), where X = Me, H, Cl) in heptane afforded the brown osmium(VI)-oxo complexes [OsO(L)(2)] (1a-c, L = N-aryl-1,2-arylenediamide) in moderate yields. The ligand L is formed in situ via oxidative ortho-C-N fusion of arylamines. The reaction occurs in an inert atmosphere, and a part of Os(VIII) is used up for the oxidation of aromatic amine. Single crystal X-ray structure of a representative complex 1a is solved. The structural analysis has authenticated the ortho-C-N fusion of ArNH(2) resulting in formation of the diamide ligand, L. The complex as a whole is penta-coordinated, and the coordination sphere has a distorted square pyramidal geometry (tau = 0.26). A similar reaction of osmium(VIII) oxide with the preformed N-phenyl-1,2-phenelene diamine produced the complex 1a in nearly quantitative yield. The substituted phenazine, 5-phenyl-3-phenylimino-3,5-dihydro-phenazine-2-ylamine, is obtained as a byproduct of the latter reaction. The complexes, 1a-c, can be reduced in a reversible one-electron step, as probed by cyclic voltammetry. The one electron reduced paramagnetic Os(V) intermediate is, however, Electron Paramagnetic Resonance (EPR) silent. Solution spectra of the osmium complexes show several multiple transitions in the UV-vis region. Density functional theory calculations were employed to confirm the structural features and to support the spectroscopic assignments. The complex 1a catalyzes oxidation of a wide variety of unsaturated hydrocarbons like alkenes, alkynes, and aldehydes to the corresponding carboxylic acids in the presence of tert-butylhydroperoxide (TBHP) efficiently at room temperature.

A simple procedure for the synthesis of substituted (E)-2-alkene-4-ynecarboxylic esters has been achieved using hydroxyapatite-supported palladium as efficient catalyst surface. The catalyst is recycled, and the turnover number (TON) based on Pd is 16000. A naphthyl-substituted derivative gives very intense fluorescence emission.

Palladium(0) nanoparticle has been used as an efficient catalyst for the allylation of active methylene compounds. Very efficient bisallylation is achieved for a variety of active methylene compounds by allyl acetate and its derivatives in one stroke in THF solvent. The reaction in water provides monoallylated product selectively by allyl acetate only. The recovered Pd(0) nanoparticle is recycled. A probable mechanism is suggested.

An efficient procedure for the stereoselective synthesis of (E)- and (Z)-2-alkene-4-ynoates and -nitriles by a simple reaction of vic-diiodo-(E)-alkenes with acrylic esters and nitriles catalyzed by in situ prepared Pd(0) nanoparticles in water has been developed. Addition of acrylic esters leads to (E)-isomers exclusively, whereas (Z)-isomers are obtained in high stereoselectivity from reactions of acrylonitrile. The aqueous slurry of Pd nanoparticles is recycled. A probable mechanism has been suggested.

A basic ionic liquid, [bmIm]OH, efficiently promotes a one-pot, three-component condensation of aldehydes, malononitrile, and thiophenols to produce highly substituted pyridines in high yields at room temperature. This reaction does not involve any hazardous organic solvent and toxic catalyst. The ionic liquid is recovered and recycled for subsequent reactions.

[reaction: see text] Diphenyl diselenide (and disulfide) undergo facile reaction with indium(I) iodide and the corresponding intermediate complex condenses in situ with a variety of substituted vinyl bromides in the presence of a catalytic amount of tetrakis(triphenylphosphine)palladium(0) [Pd(PPh3)4] in THF at room temperature to produce vinylic selenides and sulfides in good yields. The conversion of (E)-vinyl bromides is remarkably stereoselective giving (E)-vinyl selenides (and sulpfides) whereas the stereoselectivity in reaction of (Z)-vinyl bromides is not very good.

An easily accessible ionic liquid, 1-methyl-3-pentylimidazolium fluoroborate, [pmIm]BF4, has been demonstrated to be an efficient catalyst as well as reaction medium for the stereoselective debromination of a variety of structurally diverse vicinal-dibromides to the corresponding (E)-alkenes in high yields under microwave irradiation. This reaction does not require any organic solvent and any metal or any conventional reducing agent, and the ionic liquid is recycled without any appreciable loss of its catalytic efficiency.

[reaction: see text] A task-specific ionic liquid, [bmIm]OH, has been introduced as a catalyst and as a reaction medium in Michael addition. Very interestingly, although the addition to alpha,beta-unsaturated ketones proceeds in the usual way, giving the monoaddition products, this ionic liquid always drives the reaction of open-chain 1,3-dicarbonyl compounds with alpha,beta-unsaturated esters and nitriles toward bis-addition to produce exclusively bis-adducts in one stroke.

A variety of structurally diverse epoxides undergo facile cleavages by ionic liquid, [AcMIm]X without any catalyst and solvent to produce the corresponding vicinal halohydrins in high yields. The cleavages are considerably fast and highly regioselective.

Diphenyl diselenides and disulfides undergo facile cleavages by indium(I) iodide and the corresponding generated selenate and thiolate anions condense in situ with alkyl or acyl halides present in the reaction mixture. Thus, a simple, efficient, and general procedure has been developed for the synthesis of unsymmetrical diorganyl selenides, sulfides (thioethers), selenoesters, and thioesters by this one-pot reaction at room temperature., (Copyright 2004 American Chemical Society)