One-pot synthesis of symmetrical and unsymmetrical aryl sulfides by Pd-catalyzed couplings of aryl halides and thioacetates

Aryl sulfides were obtained from the coupling reaction of S-aryl (or S-alkyl) thioacetates and aryl bromides in the presence of palladium catalyst. This reaction method enables the one-pot synthesis of symmetrical and unsymmetrical diaryl sulfides by employing potassium thioacetate with aryl iodides and aryl bromides.     

Copper-mediated cross-coupling of aryl boronic acids and alkyl thiols

[reaction: see text] The cross-coupling of aryl boronic acids and alkanethiols mediated by copper(II) acetate and pyridine in anhydrous dimethylformamide affords aryl alkyl sulfides in good yield with a wide variety of substituted aryl boronic acids. The method is applicable to the synthesis of aryl sulfides of cysteine.     

Aryl 2-thienyl sulfides and aryl 2-thienyl sulfones

A method was developed for the synthesis of the previously unknown aryl 2-thienyl sulfides; the method is based on the reaction of 2-chlorothiophene and its derivatives with thiophenols in the gas phase at 450–500°C. The synthesized sulfides were oxidized to the corresponding aryl 2-thienyl sulfones, which were also previously unknown. 2,5-Dichlorothiophene reacts with excess thiophenol to give 2,5-bis(phenylthio)thiophene, which is oxidized to the corresponding disulfone.     

"One-pot" two-step synthesis of aryl sulfur compounds by photoinduced reactions of thiourea anion with aryl halides

[reaction: see text]. The photoinduced reactions of aryl halides with the thiourea anion afford arene thiolate ions in DMSO. These species without isolation, and by a subsequent aliphatic nucleophilic substitution, S(RN)1 reaction, oxidation, or protonation, yield aryl methyl sulfides, diaryl sulfides, diaryl disulfides, and aryl thiols with good yields (50-80%). This is a simple and convenient approach which involves the use of the commercially available and inexpensive thiourea in a "one-pot" two-step process for the synthesis of aromatic sulfur compounds.     

Highly chemoselective synthesis of aryl allylic sulfoxides through calcium hypobromite oxidation of aryl allylic sulfides

A highly chemoselective oxidation of widely substituted aryl allylic sulfides, prepared by allylation of arylthioethers with KF-Celite, to the corresponding aryl allylic sulfoxide was achieved by employing calcium hypobromite. Neither over-oxidation to sulfones nor halogenation of the aromatic rings was observed. The protocol may be successfully applied for the oxidation of substituted allylic systems (i.e., 2-haloallyl) that per se could interact with the oxidizing agent.     

Copper oxide nanoparticles catalyzed synthesis of aryl sulfides via cascade reaction of aryl halides with thiourea

Recyclable copper oxide nanoparticles catalyzed simple and highly efficient protocol for the synthesis of symmetrical aryl sulfides was developed by the cross-coupling of aromatic halides with inexpensive and commercially available thiourea which was used as an effective sulfur surrogate. The present cross-coupling protocol of thiourea, via cascade reaction with various substituted aryl halides, producing desired aryl sulfides, has an added advantage of avoiding foul-smelling thiols.     

Alkyl- or arylthiolation of aryl iodide via cleavage of the S-S bond of disulfide compound by nickel catalyst and zinc

Various aryl sulfides can be synthesized by nickel-catalyzed alkyl- or arylthiolation of aryl iodide with a disulfide compound. This reaction produces Ni(0) from NiBr2-bpy by the reduction with zinc, and this generated complex works as an activating species to convert ArI into ArSR under neutral conditions. Furthermore, this system enables the use of two RS groups in (RS)2.     

A facile one-pot synthesis of alkyl aryl sulfides from aryl bromides

A convenient one-pot synthetic method for the formation of alkyl aryl sulfides from various alkyl halides and lithium aryl thiolates that are prepared in situ by direct halogen-lithium exchange is reported. In particular, the method overcomes many of the problems encountered in previous reports; it is very quick, catalyst-free, and does not involve use of unstable aryl thiols.     

Transition metal catalyzed synthesis of aryl sulfides

The presence of aryl sulfides in biologically active compounds has resulted in the development of new methods to form carbon-sulfur bonds. The synthesis of aryl sulfides via metal catalysis has significantly increased in recent years. Historically, thiolates and sulfides have been thought to plague catalyst activity in the presence of transition metals. Indeed, strong coordination of thiolates and thioethers to transition metals can often hinder catalytic activity; however, various catalysts are able to withstand catalyst deactivation and form aryl carbon-sulfur bonds in high-yielding transformations. This review discusses the metal-catalyzed arylation of thiols and the use of disulfides as metal-thiolate precursors for the formation of C-S bonds.     

A general and long-lived catalyst for the palladium-catalyzed coupling of aryl halides with thiols

A general catalytic system for the coupling of aryl halides and sulfonates with thiols based on the use of the CyPF-t-Bu ligand (1) is reported. The reactions catalyzed by complexes of 1 occur in excellent yields with broad scope and exhibit extraordinary turnover numbers and high tolerance of functional groups. Turnover numbers usually exceed those of previous catalysts by 2 or 3 orders of magnitude. In addition, the reactions of aryl tosylates with alkane thiols to form aryl sulfides are reported for the first time. Finally, the synthesis of a diarylsulfide from two bromoarenes was accomplished using a hydrogen sulfide surrogate.     

Rhodium-catalyzed cleavage reaction of aryl methyl ethers with thioesters

A rhodium complex catalyzed the reaction of aryl methyl ethers and thioesters giving the corresponding aryl esters and methyl sulfides. S-(p-Chlorophenyl) p-(dimethylamino)benzothioate was used for the reaction of methyl aryl ethers with electron-withdrawing groups, and an S-(p-tolyl) derivative was used for those with electron-donating groups. Polymethoxybenzenes were converted to the esters in a regioselective manner.     

Copper mediated coupling of 2-(piperazine)-pyrimidine iodides with aryl thiols using Cu(I)thiophene-2-carboxylate

A copper-mediated synthesis of diaryl sulfides utilizing Cu(I)-thiophene-2-carboxylate (CuTC) is described. We demonstrate the use of CuTC as a soluble, non-basic catalyst in the coupling of aryl iodides and aryl thiols in the synthesis of synthetically advanced diaryl sulfides. This method allows for the successful coupling of challenging substrates including ortho-substituted and heteroaryl iodides and thiols. Additionally, most of the aryl iodide substrates used here contain the privileged piperazine scaffold bound to a pyrimidine, pyridine, or phenyl ring and thus this method allows for the elaboration of complex piperazine scaffolds into molecules of biological interest. The method described here enables the incorporation of late-stage structural diversity into diaryl sulfides containing the piperazine ring, thus enhancing the number and nature of derivatives available for SAR investigation.     

Highly efficient and magnetically separable nano-CuFe_2O_4 catalyzed S-arylation of thiourea by aryl/heteroaryl halides

The non-toxic and magnetically separable nano-CuFe_2O_4 catalyzed synthesis of symmetrical aryl sulfides by the reaction of thiourea with a wide variety of aryl halides,including aryl chlorides has been reported.Excellent yields of products have been obtained under ligand-free conditions and without the use of any expensive catalyst,such as palladium.     

Utilizing 2‐phenylpropanal as coupling partner for C‐S bond formation via sequential thioarylation and decarbonylation process: A novel strategy for the synthesis of aryl alkyl sulfides

In this study, first direct access to aryl alkyl sulfides employing 2‐phenylpropanal as coupling partner is reported. Diaryl disulfides react with this aldehyde in the presence of morpholine and produce the corresponding sulfide products in high yields. In another part, disulfides are in situ generated in the reaction mixture from aryl halides/CuI/Cyanodithioformate and coupled with 2‐phenylpropanal to access aryl alkyl sulfides.     

The preparation of aryl 1-(2,6-dimethylphenyl)-2-phenyl-4-trifluoromethyl-5-imidazolyl sulfides and sulfones

A series of aryl 1-(2,6-dimethylphenyl)-2-phenyl-4-trifluoromethyl-5-imidazolyl sulfides was prepared by displacement of fluoride from the 5-position of 1-(2,6-dimethylphenyl)-2-phenyl-4-trifluoromethyl-5-fluoroimidazole by substituted thiophenols and by benzyl mercaptan. This displacement reaction occurs much more slowly than the corresponding previously described reactions of 4-trifluoromethyl-5-fluorothiazoles and -oxazoles. Several solvent-base pairs were examined; the reaction was found to work best when dimethyl sulfoxide was used as the solvent and diazabicycloundecene as the base. The sulfides were oxidized to sulfones by treatment with hydrogen peroxide in acetic acid.     

The reaction of N-R-2-cyanothioacetamides with ethyl[(aryl)hydrazono]chloroacetates

Depending on the nature of the substituents in the starting reagents and the basicity of the medium the cyclization of N-R-2-cyanothioacetamides with ethyl [(aryl)hydrazono]chloroacetates gives 3-aryl-2-cyanomethylidene-5-ethoxycarbonyl-1,3,4-thiadiazoles, 5-arylhydrazono-2-cyanomethylidene-3-phenyl-thiazolidin-4-ones, di[(aryl)hydrazono](ethoxycarbonylmethyl) sulfides, and 5-amino-3-cyano-2-phenyl-amino-4-(N-phenylaminothiocarbonyl)thiophene. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp 109–114, January, 2007.     

Efficient recyclable CuI-nanoparticle-catalyzed S-arylation of thiols with aryl halides on water under mild conditions

CuI nanoparticles efficiently catalyzed the C-S cross coupling of aryl and alkyl thiols with aryl halides in the absence of ligands on water under mild conditions. A wide range of diaryl sulfides and aryl alkyl sulfides are synthesized in good to excellent yields utilizing this protocol. This procedure is particularly noteworthy given its mild conditions, avoiding the undesired formation of disulfides through oxidation of thiols. The recovery and successful reutilization of the catalyst is described. Furthermore, the directed synthesis of bisarylated product is presented.     

Synthesis of di(hetero)aryl sulfides by directly using arylsulfonyl chlorides as a sulfur source

A new, efficient protocol for the synthesis of di(hetero)aryl sulfides is described. Cheap and easily available arylsulfonyl chlorides as a sulfur source reductively couple with electron-rich (hetero)arenes (e.g., indolizines, indoles, electron-rich benzenes, etc.) in the presence of triphenylphosphine to afford di(hetero)aryl thioethers in good yields.     

Rapid synthesis of aryl sulfides through metal-free C–S coupling of thioalcohols with diaryliodonium salts

An efficient, general, and highly selective method for the synthesis of aryl sulfides has been developed through metal-free, direct C–S coupling from thioalcohols and diaryliodonium salts. Significantly, the reaction took only 10 min to complete and produced high yields at room temperature. Thus, this methodology proves its value as a versatile synthetic choice for a broad range of aryl sulfides, producing good to excellent yields.     

Copper-catalyzed direct preparation of diaryl sulfides from aryl iodides using potassium thiocyanate as a sulfur transfer reagent

A method for direct preparation of diaryl sulfides from aryl iodides using potassium thiocyanate as a sulfur-transfer agent is reported. A catalyst system comprising of a simple copper salt, tetrabutylammonium bromide as a phase-transfer agent and water as the solvent is used. Microwave heating at 200 °C for 60 min allows for the conversion of a range of aryl iodides to the corresponding diaryl sulfides.