Diorganyl Dichalcogenides Research Articles

Copper-Catalyzed Synthesis of Unsymmetrical Diorganyl Chalcogenides (Te/Se/S) from Boronic Acids under Solvent-Free Conditions.

The efficient and mild copper-catalyzed synthesis of unsymmetrical diorganyl chalcogenides under ligand- and solvent-free conditions is described. The cross-coupling reaction was performed using aryl boric acids and 0.5 equiv. of diorganyl dichalcogenides (Te/Se/S) in the presence of 3 mol % of CuI and 3 equiv. of DMSO, under microwave irradiation. This new protocol allowed the preparation of several unsymmetrical diorganyl chalcogenides in good to excellent yields.

Metal- and Solvent-Free Approach to Access 3-Se/S-Chromones from the Cyclization of Enaminones in the Presence of Dichalcogenides Catalyzed by KIO3.

Herein, we describe a greener protocol for the one-pot synthesis of 3-Se/S-4H-chromen-4-ones. The desired products were obtained in good to excellent yields using 2-hydroxyphenyl enaminones and half equivalents of various odorless diorganyl dichalcogenides (S/Se) in the presence of glycerol (5 molar equiv) and KIO3 (15 mol %) as the catalyst under solvent-free conditions.

Copper‐Catalyzed Carbon‐Nitrogen/Carbon‐Selenium Bonds Formation: Synthesis of 2‐(Organochalcogenyl)‐indolizines

AbstractThe copper‐catalyzed cyclization of propargylpyridines with diorganyl dichalcogenides was applied to the synthesis of 2‐(organochalcogenyl)‐indolizines. A systematic study of the cyclization system revealed that the mutual action between copper(I) iodide and diorganyl dichalcogenides is essential for the formation of indolizines in good yields avoiding the formation of hydrogenated indolizine. The standard reaction conditions were compatible with many functional groups in the substrates, such as methyl, chlorine, fluorine, methoxy and trifluoromethyl. This protocol was efficient with diorganyl diselenides and ditellurides but ineffective with diorganyl disulfides. In addition, the obtained 2‐(organochalcogenyl)‐indolizines were readily transformed into more complex products by reaction with boronic acids using palladium‐catalyzed cross‐coupling conditions.magnified image

Selective Synthesis of 4‐Chalcogenylmethyl‐1,3‐dioxolan‐2‐ones and 1,3‐Bis(organylchalcogenyl)propan‐2‐ols from 3‐O‐Tosyl Glycerol 1,2‐Carbonate

AbstractWe describe a selective method for synthesis of 4‐chalcogenylmethyl‐1,3‐dioxolan‐2‐ones and 1,3‐bis(organylchalcogenyl)propan‐2‐ols in a short reaction time through stoichiometric control. The use of 3‐O‐tosyl glycerol 1,2‐carbonate and a set of aryl and alkyl diorganyl dichalcogenides afforded the desired products in good to excellent yields. We also describe a synthetic application to 4‐chalcogenylmethyl‐1,3‐dioxolan‐2‐ones by base promoted the synthesis of 3‐(arylchalcogenyl)propane‐1,2‐diols in excellent yields.

ChemInform Abstract: Efficient Synthesis of Unsymmetrical Heteroaryl Thioethers and Chalcogenides by Alkali Hydroxide‐Mediated SNAr Reactions of Heteroaryl Halides and Dichalcogenides.

An efficient alkali hydroxide-mediated SNAr reaction of heteroaryl halides has been developed for the practical synthesis of the useful unsymmetrical heteroaryl thioethers and chalcogenides. The usually odorless, easily available, lowly toxic, and easily stored and handled diorganyl dichalcogenides can be used as safer and convenient chalcogen nucleophile precursors and diverse unsymmetrical heteroaryl chalcogenides can be obtained in good to high yields by the method.

Efficient synthesis of unsymmetrical heteroaryl thioethers and chalcogenides by alkali hydroxide-mediated SNAr reactions of heteroaryl halides and dichalcogenides

An efficient SNAr reaction of heteroaryl halides and diorganyl dichalcogenides is developed for practical synthesis of the useful unsymmetrical heteroaryl thioethers and chalcogenides.

Diorganyl Dichalcogenides-Promoted Nucleophilic Closure of 1,4-Diyn-3-ols: Synthesis of 2-Benzoyl Chalcogenophenes.

We report here the preparation of chalcogenophene derivatives via cyclization reactions of diynols promoted by diorganyl dichalcogenides and a halogen source. Different chalcogenophenes, such as 4-halo-selenophenes, 4-butylselenyl-selenophenes, halo-thiophenes, and 4-methylthio-thiophenes, were selectively prepared in good yields from the same starting materials. The results revealed that the halogen source had a significant effect on the proportion of 4-bromo-selenophenes and 4-butylselenyl-selenophenes. The best yields of 4-iodo-selenophenes were obtained with iodine as a halogen source, while the use of NBS gave exclusively the 4-butylselenyl-selenophenes. The experiments also revealed that the cyclization reaction to form 4-halo-thiophene derivatives can also be controlled changing the ratios of reagents. The 4-iodo-thiophenes were exclusively obtained by using dimethyl disulfide (2.0 equiv) and iodine (1.5 equiv), while the 4-bromo-thiophenes were obtained when the reaction was carried out with a 1.5 molar ratio of dimethyl disulfide and a halogen source. In addition, the reaction of diynols with an excess of dimethyl disulfide in the presence of NBS gave the 4-methylthio-thiophenes as sole products. We also studied the application of chalcogenophenes obtained as starting materials in the Suzuki, Sonogashira, and Ullmann cross-coupling reactions.

ChemInform Abstract: Synthesis of Unsymmetrical Diorganyl Chalcogenides under Greener Conditions: Use of an Iodine/DMSO System, Solvent‐ and Metal‐Free Approach.

AbstractThe use of iodine as the catalyst and DMSO as the oxidant renders possible the coupling of diorganyl dichalcogenides with arylboronic acids and vinyltrifluoroborate (VIII) to give the title products in good yields.

ChemInform Abstract: Nucleophilic Cyclization of o‐Alkynylbenzamides Promoted by Iron(III) Chloride and Diorganyl Dichalcogenides: Synthesis of 4‐Organochalcogenyl‐1H‐isochromen‐1‐imines.

AbstractA facile protocol for the reaction of o‐alkynylbenzamides with diorganyl dichalcogenides is presented.

Synthesis of Unsymmetrical Diorganyl Chalcogenides under Greener Conditions: Use of an Iodine/DMSO System, Solvent‐ and Metal‐Free Approach

AbstractHerein, we report a greener iodine‐catalyzed protocol to access different types of unsymmetrical diorganyl chalcogenides. This new approach works in the absence of solvent and metal. The desired products were obtained in good to excellent yields using one equivalent of arylboronic acids, half an equivalent of various diorganyl dichalcogenides, iodine (10 mol%) as a catalyst and 2 equivalents of dimethyl sulfoxide (DMSO; as oxidant), with a reaction time of 10 min under microwave irradiation.magnified image

ChemInform Abstract: Direct Michael Addition to Electron‐Deficient Alkenes Using Diorganyl Dichalcogenides (Te/S) and NaBH4/PEG‐400.

Abstract Nucleophilic species of tellurium and sulfur were generated in situ from the reaction of the respective diorganyl dichalcogenides with NaBH 4 in PEG-400 as solvent and selectively added to electron-deficient alkenes. Chalcogenolate anions were directly added at mild conditions by this simple procedure and in all cases furnished the respective Michael adducts in short reaction times and good yields.

Nucleophilic Cyclization of o‐Alkynylbenzamides Promoted by Iron(III) Chloride and Diorganyl Dichalcogenides: Synthesis of 4‐Organochalcogenyl‐1H‐isochromen‐1‐imines

AbstractWe have developed a method for the preparation 4‐organochalcogenyl‐1H‐isochromen‐1‐imines from o‐alkynylbenzamides. This electrophile‐promoted nucleophilic cyclization achieved by treatment with a combination of iron salts and diorganyl dichalcogenides. FeCl3 and diorganyl dichalcogenides reacted with o‐alkynylbenzamides under aerobic conditions at room temperature and in the absence of additives to give 4‐organochalcogenyl‐1H‐isochromen‐1‐imines in good yields and with good selectivities. The reaction took place with 0.5 equiv. of the diorganyl dichalcogenides, which demonstrates that both halves of the diorganyl dichalcogenides (RYYR → 2RY) were incorporated into the final product. Mechanistic studies suggested that the regioselectivity of the cyclization is governed by a seleniranium ion, a key intermediate formed by the electrophilic addition of the organochalcogen moiety to the carbon–carbon triple bond. The utility of the 4‐organochalcogenyl‐1H‐isochromen‐1‐imines was also demonstrated by their application as starting materials in Suzuki and Sonogashira cross‐coupling reactions.

ChemInform Abstract: α‐Organylchalcogenation of Aldehydes and Ketones with Diorganyl Dichalcogenides Promoted by K3PO4.

AbstractVarious aldehydes and ketones react with diorganyl dichalcogenides under mild reaction conditions leading to the corresponding α‐organylseleno and α‐arylthio carbonyl compounds.

ChemInform Abstract: Magnetite (Fe3O4) Nanoparticles: An Efficient and Recoverable Catalyst for the Synthesis of Alkynyl Chalcogenides (Selenides and Tellurides) from Terminal Acetylenes and Diorganyl Dichalcogenides.

Abstract We present herein a new and efficient methodology for the synthesis of alkynyl chalcogenides from terminal acetylenes and diorganyl dichalcogenides, catalyzed by Fe3O4 nanoparticles. This new approach provided the desired products in good to excellent yields. Moreover, the catalyst was easily recoverable using an external magnet and reused for further experiments without loss of catalytic activity.

Direct Michael addition to electron-deficient alkenes using diorganyl dichalcogenides (Te/S) and NaBH4/PEG-400

Nucleophilic species of tellurium and sulfur were generated in situ from the reaction of the respective diorganyl dichalcogenides with NaBH4 in PEG-400 as solvent and selectively added to electron-deficient alkenes. Chalcogenolate anions were directly added at mild conditions by this simple procedure and in all cases furnished the respective Michael adducts in short reaction times and good yields.

CuI/glycerol mediated stereoselective synthesis of 1,2-bis-chalcogen alkenes from terminal alkynes: synthesis of new antioxidants

(E)-1,2-Bis-chalcogen alkenes were stereoselectively prepared in good yields by the addition of diorganyl dichalcogenides to terminal alkynes using CuI/Zn/glycerol as a recyclable catalytic system. The antioxidant activity in vitro of four (E)-1,2-bis-chalcogen alkenes synthesized was evaluated and (E)-1,2-bis-(4-methoxyphenylselanyl)styrene 3b presented excellent activity. The catalytic system used in the synthesis was recovered and used directly up to 5 cycles without loss of activity.

A General and Highly Efficient Protocol for the Synthesis of Chalcogeno­acetylenes by Copper(I)-Terpyridine Catalyst

A highly efficient copper-catalyzed Csp–X (X = S, Se, Te) bond-forming reaction of terminal alkynes and diorganyl dichalcogenides has been developed. This transformation was realized through the use of copper(I) iodide as a catalyst, 4′-(4-methoxyphenyl)-2,2′:6′,2′′-terpyridine as a ligand, and K3PO4 as a base. A variety of the functionalized substrates were found to react under these reaction conditions to provide products in good to excellent yields.

A Solvent- and Metal-Free Synthesis of 3-Chacogenyl-indoles Employing DMSO/I2as an Eco-friendly Catalytic Oxidation System

Herein, we describe a solvent- and metal-free method for the synthesis of 3-chalcogenyl-indoles from indoles and diorganyl dichalcogenides using an equivalent amount of DMSO as an oxidant, under catalysis by molecular iodine. This mild and eco-friendly approach allowed the preparation of a wide range of 3-selenyl- and 3-sulfenyl-indoles in good to excellent yields.

α-Organylchalcogenation of aldehydes and ketones with diorganyl dichalcogenides promoted by K3PO4

A new catalytic method for direct a-organ- ylchalcogenation of aldehydes and ketones has been developed. When various aldehydes and ketones were allowed to react with diorganyl dichalcogenides in the presence of K3PO4, under mild reaction conditions, the corresponding a-organylseleno and a-arylthio aldehydes and ketones were obtained in good to high yields.

Diorganyl dichalcogenides with intramolecular coordination interactions: the synthesis and structure of bis(4,6-dimethylpyrimidin-2-yl) diselenide

Bis(4,6-dimethylpyrimidin-2-yl) diselenide, a new representative of dihetaryl diselenides, was obtained by successively treating selenourea with hydrochloric acid, acetylacetone, potassium hydroxide, and the system iodine—potassium iodide. The unusual planar trans-conformation of this compound (X-ray diffraction data) is stabilized by intramolecular attractive nonvalent Se…N interactions (Se…N, 2.926(1) A) and stacking of the π-systems of the aromatic heterocycles (the centers of the pyrimidine rings are spaced apart at 3.365(2) A). The energy parameters of the factors that make the molecular structure flattened were estimated by quantum chemical DFT calculations.