Carbon Sulfur Bond Formation Research Articles

Carbon-Sulfur Bond Formation via Metal-Catalyzed Allylations of Sulfur Nucleophiles

The development of practical approaches for the construction of carbon–sulfur bonds is of interest to scientists. In particular, carbon–sulfur bond formation by transition-metal-catalyzed allylations has been attracting great attention. Allylic sulfides are important substances owing to their broad applications in synthetic and pharmaceutical areas. The alkene and sulfur moieties in allylic sulfides can lead to numerous transformations. This review details the development of carbon–sulfur bond formation through palladium-catalyzed rearrangements, palladium-catalyzed allylations, ­iridium-catalyzed regio- and enantioselective allylations and miscellaneous metal-catalyzed allylic substitutions. Carbon–selenium bond formations via metal-catalyzed allylic substitutions are also reviewed. 1 Introduction 2 Carbon–Sulfur Bond Formation via Palladium-Catalyzed Reactions 2.1 Rearrangements of Allylic Substrates 2.2 Allylations 2.3 Asymmetric Allylations 3 Carbon–Sulfur Bond Formation via Iridium-Catalyzed Regio­- and Enantioselective Allylations 4 Carbon–Sulfur Bond Formation via Miscellaneous Metal-Catalyzed Reactions 4.1 Nickel 4.2 Ruthenium 4.3 Gallium 4.4 Iron 5 Carbon–Selenium Bond Formation via Metal-Catalyzed Allylic­ Substitutions 6 Conclusions

Nano-Structured Metal Chalcogenides as Reagents for the Catalytic Carbon–Sulfur Bond Formation in Cross-Coupling Reaction

A new approach for the catalytic carbon–sulfur bond formation via cross-coupling reaction is reported. For the first time nano-structured nickel organosulfides [Ni(SAr)2] n were used as a source of SAr groups in catalytic cross-coupling reaction. A unique effect of morphology control of the reactivity of SAr groups in cross-coupling reaction was found. Synthesized nano-structured particles were characterized by field-emission scanning electron microscopy and their reactivity was studied by NMR in solution. Cross-coupling reaction with Cu catalyst was shown to proceed in the liquid phase and involve leaching, whereas the reaction with Pd catalyst is more complex and may involve both—homogeneous and heterogeneous pathways.

ChemInform Abstract: Catalytic Activation of Olefins by Metal Triflates and Triflimides: Application to Fragrance Chemistry

AbstractReview: 61 refs.

Catalytic Activation of Olefins by Metal Triflates and Triflimides: Application to Fragrance Chemistry

Fragrance compounds constitute a wide family of relatively volatile compounds presenting interesting odour properties. Several processes catalysed by metal triflates and triflimides have been recently developed with a view to applications to fragrance chemistry. These reactions, involving the activation of non-activated olefins, mainly involve inter- and intramolecular carbon-carbon, carbon-oxygen and carbon-sulfur bond formation.

Central Composite Experimental Design Applied to the Catalytic Carbon-Sulfur Bond Formation by Fluorapatite Catalyst

The aim of this study was to apply experimental design in the optimization of the thia-Michael addition reaction between chalcone derivatives and mercaptans catalyzed by Fluorapatite catalyst (FAP). The central composite design was used to design an experimental program to provide data to model the effects of various factors on reaction yield (Y). The variables chosen were catalyst weight (X1), reaction time (X2) and solvent volume (X3). The mathematical relationship of reaction yield on the three significant independent variables can be approximated by a nonlinear polynomial model. Predicted values were found to be in good agreement with experimental values. The optimum reaction conditions (x1= 350 mg, x2= 30 min and x3= 2 mL) for reaction model (chalcone and thiophenol) obtained by response surface were applied to other substrates. This study has shown that central composite design could efficiently be applied for the modeling of catalytic carbon-sulfur bond formation by FAP catalyst under mild reaction condition with high yield, and it is an economical way of obtaining the maximum amount of information with the fewest number of experiments.

Response Surface Methodology for the Optimization of Thia-Michael Addition Reaction Catalyzed by Doped Fluorapatite

The aim of this study was to apply central composite experimental design in the thia-Michael addition reaction between chalcone derivatives and mercaptans catalyzed by doped Fluorapatite catalyst (KF/FAP). Central composite design was used to create an experimental program to provide data to model the effects of various factors on reaction yield of thia-Michael addition (Y). The variables chosen were reaction time (X1), solvent volume (X2), catalyst weight (X3) and impregnation ratio (X4). The mathematical relationship between reaction yield and four significant independent variables can be approximated by a second-order quadratic model. Response surface methodology was used to describe the individual and interactive effects of four variables at five levels, combined according to a central composite design. This study has shown that central composite design can be applied to the catalytic carbon-sulfur bond formation in mild reaction condition with high yield, and it is an economical way of obtaining the maximum amount of information with the fewest experiments.

Silver catalyzed C–C and C–S coupling of aryl halides and thiols with boronic acids

An efficient Ag(I) catalyzed carbon–carbon and carbon–sulfur bond formation reaction of aryl halides and thiols with boronic acids has been demonstrated. Using this protocol, substrates with a wide range of functional group including electron-rich, and electron deficient substituents have been explored. These reactions are particularly useful to prepare symmetrical and unsymmetrical biphenyls and thioethers. These products were isolated in high yield.

Metal triflates and triflimides as Lewis “superacids”: preparation, synthetic application and affinity tests by mass spectrometry

Metal salts of triflic acid, CF3SO2OH and of triflimidic acid, [CF3SO2]2NH, often called “Lewis superacids”, are powerful catalysts for several classes of reactions. Typical applications developed at the Institut de Chimie de Nice during the last decade, mostly in the domain of inter‐ and intramolecular carbon–carbon, carbon–oxygen and carbon–sulfur bond formation, are illustrated. During the last three years, the characterization of metal triflates and triflimides by electrospray mass spectrometry was also accomplished in our Institute. Displacement of one anion of the salt by strong neutral ligands was developed as a mean for generating characteristic positive ions. In an effort toward the quantitative description of the ligand/metal bonding and the catalytic role of the Lewis acid, a ligand competition method was devised. An exploratory study attests that subtle structural effects on the donor/acceptor interaction can be evidenced using this simple mass spectrometric method. Copyright © 2012 John Wiley & Sons, Ltd.

A Bioinspired ZnII/FeIII Heterobimetallic Catalyst for Thia-Michael Addition

A novel tetranuclear ZnII/FeIII heterobimetallic complex was synthesized, and the complex can efficiently catalyze the Michael addition of thiophenols to α,β-unsaturated enones, even for tertiary carbon–sulfur bond formation.

ChemInform Abstract: Carbon—Sulfur Bond Formation of Challenging Substrates at Low Temperature by Using Pd‐PEPPSI‐IPent.

AbstractA variety of aromatic and heteroaromatic bromides, including highly sterically congested ones, reacts with thiols to afford the corresponding thioethers with yields up to 99%.

ChemInform Abstract: Enantioselective Carbon—Sulfur Bond Formation: γ‐Additions of Aryl Thiols to Allenoates Catalyzed by a Chiral Phosphepine.

AbstractAn axially chiral phosphepine efficiently catalyzes the asymmetric addition of arylthiols to the γ‐position of allenoates.

ChemInform Abstract: A Mild and Highly Efficient One‐Pot Three‐Component Reaction for Carbon—Sulfur Bond Formation Catalyzed by Potassium tert‐Butoxide.

AbstractBest conditions are found with tBuOH at room temperature.

Alkyne Addition to a Metal‐Stabilized Thiyl Radical: Carbon–Sulfur Bond Formation between 1‐Octyne and [Ru(SP)3]+

AbstractThe metal‐stabilized thiyl radical complex [Ru(SP)3]+, [Ru‐1]+, {SP = 2‐(diphenylphosphanyl)benzenethiolate} adds 1‐octyne across the cis‐sulfur sites to yield the S‐alkylated dithiolene product [Ru‐1·octyne]+. The product complex exists as a pair of inseparable geometric isomers, which were characterized by X‐ray crystallography, 31P NMR spectroscopy, and cyclic voltammetry. By using electrochemical methods, the rate constant for 1‐octyne addition was determined as 8.7 × 103 M–1 s–1.

Carbon–Sulfur Bond Formation of Challenging Substrates at Low Temperature by Using Pd‐PEPPSI‐IPent

A variety of aromatic and heteroaromatic bromides, including highly sterically congested ones, reacts with thiols to afford the corresponding thioethers with yields up to 99%.

Reduction of the [2Fe–2S] Cluster Accompanies Formation of the Intermediate 9-Mercaptodethiobiotin in Escherichia coli Biotin Synthase

Biotin synthase catalyzes the conversion of dethiobiotin (DTB) to biotin through the oxidative addition of sulfur between two saturated carbon atoms, generating a thiophane ring fused to the existing ureido ring. Biotin synthase is a member of the radical SAM superfamily, composed of enzymes that reductively cleave S-adenosyl-l-methionine (SAM or AdoMet) to generate a 5'-deoxyadenosyl radical that can abstract unactivated hydrogen atoms from a variety of organic substrates. In biotin synthase, abstraction of a hydrogen atom from the C9 methyl group of DTB would result in formation of a dethiobiotinyl methylene carbon radical, which is then quenched by a sulfur atom to form a new carbon-sulfur bond in the intermediate 9-mercaptodethiobiotin (MDTB). We have proposed that this sulfur atom is the μ-sulfide of a [2Fe-2S](2+) cluster found near DTB in the enzyme active site. In the present work, we show that formation of MDTB is accompanied by stoichiometric generation of a paramagnetic FeS cluster. The electron paramagnetic resonance (EPR) spectrum is modeled as a 2:1 mixture of components attributable to different forms of a [2Fe-2S](+) cluster, possibly distinguished by slightly different coordination environments. Mutation of Arg260, one of the ligands to the [2Fe-2S] cluster, causes a distinctive change in the EPR spectrum. Furthermore, magnetic coupling of the unpaired electron with (14)N from Arg260, detectable by electron spin envelope modulation (ESEEM) spectroscopy, is observed in WT enzyme but not in the Arg260Met mutant enzyme. Both results indicate that the paramagnetic FeS cluster formed during catalytic turnover is a [2Fe-2S](+) cluster, consistent with a mechanism in which the [2Fe-2S](2+) cluster simultaneously provides and oxidizes sulfide during carbon-sulfur bond formation.

A Dedicated Glutathione S-Transferase Mediates Carbon–Sulfur Bond Formation in Gliotoxin Biosynthesis

Gliotoxin is a virulence factor of the human pathogen Aspergillus fumigatus , the leading cause of invasive aspergillosis. Its toxicity is mediated by the unusual transannular disulfide bridge of the epidithiodiketopiperazine (ETP) scaffold. Here we disclose the critical role of a specialized glutathione S-transferase (GST), GliG, in enzymatic sulfurization. Furthermore, we show that bishydroxylation of the diketopiperazine by the oxygenase GliC is a prerequisite for glutathione adduct formation. This is the first report of the involvement of a GST in enzymatic C-S bond formation in microbial secondary metabolism.

A mild and highly efficient one-pot three-component reaction for carbon–sulfur bond formation catalyzed by potassium tert-butoxide

Abstract Potassium tert-butoxide has been found to be a highly efficient catalyst for one-pot, three-component reaction of aryl aldehydes, acetophenones, and thiols via Claisen–Schmidt/Michael addition reactions for the synthesis of thia-Michael adducts in high yields. The reactions are best carried out in tert-butyl alcohol at room temperature.

ChemInform Abstract: Carbon—Sulfur Bond Formation via Iridium‐Catalyzed Asymmetric Allylation of Aliphatic Thiols.

AbstractThe reaction allows highly regio‐ and enantioselective formation of α‐branched allyl alkyl sulfides.

ChemInform Abstract: Organometallic Approaches to Carbon—Sulfur Bond Formation

AbstractReview: 259 refs.

Synthetically useful carbon–carbon and carbon–sulphur bond construction mediated by carbon- and sulphur-centred radicals in water and aqueous media

This account is focused on carbon–carbon, and carbon–sulphur bond-forming reactions through the use of carbon- and sulphur-centred radicals in water, respectively. It intends to show the scope and applications of these types of radicals with a synthetic goal, thus helping the radical synthetic chemist to grasp the fundamental aspects of the syntheses of a wide array of organic compounds through radical methods in environmentally friendly media. This account excludes the syntheses of organic substrates with the aid of organometallic/metal-centred radicals such as other Group IV-radicals and transition-metal radicals, and the important class of radical reductions currently accomplished in water using different metallic reducing species. The array of substrates synthesized through the present method encompasses intermolecular and intramolecular radical carbon–carbon bond formation reactions in water, and radical carbon–sulphur bond formation reactions. Among the radical carbon–carbon bond formation reactions, special attention is devoted to atom-transfer radical reactions, radical addition reactions to olefins, radical addition to carbon–nitrogen double bonds, the carboaminohydroxylation of alkenes, and the analogues of Knovonoegel reactions, the synthesis of functionalized enol ethers, thr carboazidation and azidation, and ynol formation, and radical cyclization reactions in water.