Glycerol as a promoting medium for cross-coupling reactions of diaryl diselenides with vinyl bromides

We described herein the use of glycerol as a novel solvent in the cross-coupling reaction of diaryl diselenides with vinyl bromides catalyzed by CuI. This cross-coupling reaction was performed with diaryl diselenides and (Z)- or (E)-vinyl bromides bearing electron-withdrawing and electron-donating groups, affording the corresponding vinyl selenides in good to excellent yields. The mixture glycerol/catalyst can be directly reused for further cross-coupling reactions.     

Bimetallic system for the synthesis of diorganyl selenides and sulfides, chiral β-seleno amines, and seleno- and thioesters

The bimetallic reagent Sn(II)/Cu(II) in [bmim]BF₄ was efficiently used for the cleavage of diaryl diselenides and disulfides and reacts with a variety of organic substrates, such as organic halides, acid chlorides, and β-amino mesylates affording the diorganyl selenides and sulfides within very short reaction times, under mild conditions and with excellent yields, using BMIM-BF₄ as a reusable solvent.     

三溴化金催化端炔与二芳基二硒醚反应合成炔基硒醚

炔基硒醚是合成一些有机硒化合物的重要起始物。本文研究发现,在三溴化金(Au Br3)催化下,端位炔和二芳基二硒醚在弱碱(如碳酸钾)存在下反应,生成炔基芳基硒醚,产率为69%~98%;在空气参与下,于80℃下进行反应,反应条件简单,且二硒醚的两个硒原子均可以被利用。二甲基亚砜(DMSO)是合适的溶剂,在极性较小的溶剂(如甲苯、四氢呋喃)中,此反应不能进行。芳基炔(如苯乙炔、对甲基苯乙炔、对氯苯乙炔等)、烯基炔(如环己烯乙炔)和烷基炔(如1-壬炔)均能顺利进行此反应。当芳基炔苯环的间位或邻位连有取代基时,反应产率较低(69%~82%),而对位无论是连有吸电子基还是给电子基,该反应均可以得到很高的产率(95%)。     

A convenient and efficient copper-catalyzed synthesis of unsymmetrical and symmetrical diaryl chalcogenides from arylboronic acids in ethanol at room temperature

A simple and convenient approach for the synthesis of unsymmetrical diaryl chalcogenides (Te, Se, and S) has been developed by copper-catalyzed cross-coupling reaction of organoboronic acid with diaryl dichalcogenide in ethanol using NaBH₄ in air or oxygen. The present methodology is highly practical for the synthesis of unsymmetrical diaryl tellurides with various functionalities such as –NO₂, –F, –Br, and –COOH that have been obtained in good to excellent yields. Methodology is also effective for the synthesis of unsymmetrical diaryl selenides and sulfides. Moreover, symmetrical diaryl selenides have also been obtained from arylboronic acids using elemental selenium powder under optimized reaction conditions. The use of NaBH₄ is the key for the development of milder reaction conditions, which enable the construction of unsymmetrical diaryl chalcogenides from boronic acid substrates in ethanol at room temperature.     

Facile synthesis of symmetrical 3,3-diarylacrylates by a Heck-Matsuda reaction: an expedient route to biologically active indanones

A simple and straightforward synthesis of symmetrical 3,3-diarylacrylates based on a Heck-Matsuda reaction of arenediazonium salts bearing electron-donating groups with methylacrylates is described. The reaction employs Pd(OAc)₂ as catalyst and goes to completion within 1 h affording the corresponding unsaturated diaryl esters in good to high yields. This method permitted the expeditious and efficient synthesis of the anticancer 3-arylindanone 5 in two operative steps in 43% overall yield.     

二碘化钐促进的β-羟基不对称硒(碲)醚的合成

二芳基二硒(碲)醚在SmI2作用下, Se-Se(Te-Te)键还原断裂生成的硒(碲)负离子与环氧化物反应, 得到β-羟基不对称硒(碲)醚。     

A Novel Synthesis of Benzyl Sulfides and Selenides via Sm/BiCl3 System in Aqueous Media

Benzyl sulfides and selenides are synthesized via reaction of benzyl bromide with disulfides and diselenides promted by Sm/BiCl₃ system in aqueous media in moderate to good yields.     

Efficient synthesis of diorganyl selenides via cleavage of Se-Se bond of diselenides by indium(III) catalyst and zinc

A simple and efficient procedure for the synthesis of unsymmetrical diorganyl selenides from an one-pot indium(III) catalyzed procedure, in the presence of zinc, has been developed. Various organic halides and even the unreactive organic chlorides underwent the reaction efficiently. Also diaryl and dialkyl diselenides underwent the coupling reaction.     

A simple preparation of symmetrical and unsymmetrical diarylsulfides from arenediazonium tetrafluoroborates

The reaction between arenediazonium tetrafluoroborates and arenethiolates in Me₂SO represents a mild, efficient, and safe alternative to the Ziegler synthesis of diaryl sulfides.     

Synthesis of Allyl Selenides Promoted by an Sm/ZnCl2 Bimetal System in the Presence of Water

The reaction of diselenides with allylic bromides proceeded smoothly in an Sm/ZnCl₂ bimetal system in THF‐H₂O to afford allyl selenides in good yield.     

Transition metal free K2CO3 mediated thioarylation,selenoarylation and arylation of 2-aminomaleimides at ambient temperature

Transition metal free thioarylation, selenoarylation and arylation of 2-aminomaleimide, using thiophenols, diaryl diselenides and arylhydrazine hydrochlorides respectively, has been reported in DMSO under aerobic condition in presence of K₂CO₃ at room temperature. The reaction occurs smoothly without prerequisite N-protection of 2-aminomaleimide. The synthesis of novel, polyfunctionalized maleimides has been achieved by the direct C–H activation of enamines. Thioarylation and selenoarylation are proposed to be proceeding via disulfides/diselenides and arylation has been proposed to be proceeding via aryl free radicals.     

Organic Diselenides and Ditellurides: Disproportionations,Synthesis of Stannyl Selenides,Reactions with Acetylenes

The disproportionation reaction of organic diselenides 1 and ditellurides 2, the synthesis of stannyl selenides 4, and the addition reaction (palladium-catalyzed, thermal) of dialkyl diselenides to acetylenes are discussed.     

New decarboxylative chalcogenation of aliphatic and alicyclic carboxylic acids.

Thiohydroxamic-carboxylic mixed anhydrides can be decarboxylated in the presence of diaryl disulphides, diselenides and ditellurides to give sulphides, selenides and tellurides respectively in reasonable to good yield.     

The use of aminoiminomethanesulfinic acid (thiourea dioxide) under phase transfer conditions for generating organochalcogenate anions. Synthesis of sulfides,selenides and tellurides

A procedure is described which allows for the in situ synthesis of arylalkyl, diaryl and dialkylchalcogenides under phase transfer conditions starting from the corresponding diorganodichalcognides. The dichalcogenides are reduced by aminoiminomethanesulfinic acid (thiourea dioxide) in alkaline medium and catalyzed by a quaternary ammonium salt. The reduction proceeds easily for diaryl disulfides and diaryl diselenides at a sodium hydroxide concentration of 13%; diaryl ditellurides require a 50% sodium hydroxide solution to give the aryl tellurolate anion. The dialkyl diselenides and dialkyl ditellurides are more difficult to reduce. The intermediate arylthiolates and arylselenolates are quenched by alkyl and activated aryl halides to give the corresponding sulfides and selenides in high yield (77–97%). The aryltellurolates react with alkyl halides giving the aryl alkyl tellurides in 81–96% yield. The procedure could not be successfully used for the synthesis of dialkylselenides and dialkyl tellurides; low yields and mixture of products were formed.     

Copper-catalyzed three-component reaction of ethynylstibanes,organic azides,and selenium: A simple and efficient synthesis of novel selenides and diselenides having 1,2,3-triazole rings

A simple method for the synthesis of monoselenides and diselenides having 1,2,3-triazole ring is described herein. The three component reaction of ethynylstibanes, organic azides, and selenium powder is catalyzed by CuI (10?mol%) using 1,10-phenanthroline as the ligand (10?mol%) under aerobic conditions. Either selenides or diselenides can be synthesized by selecting the appropriate amount of selenium powder for otherwise identical reaction conditions. The obtained selenides and diselenides having a 1,2,3-triazole ring are all novel compounds. By using an antimony reagent, this one-pot reaction provides regioselective double Se-arylation under simple reaction conditions.     

Palladium catalyzed Heck reaction of arenediazonium tetrafluoroborate salts with Baylis-Hillman adducts: production of α-benzyl-β-keto esters

A novel experimental procedure to obtain α-benzyl-β-keto esters from the Heck reaction between arenediazonium tetrafluoroborate salts and Baylis-Hillman (BH) adducts in the presence of Pd(OAc)₂ as catalyst is described. The methodology is simple, straightforward and the use of arenediazonium salts as opposed to conventional arylhalides/triflates over the usual Heck reaction is highlighted.     

Hypervalent Iodine in Synthesis XV: A Convenient New Method for the Preparation of Unsymmetrical Diaryl Selenides

Unsymmetrical diaryl selenides have been prepared by the reaction of sodium areneselenolates with diaryliodonium salts in DMF.     

Visible light-promoted,iodine-catalyzed selenoalkoxylation of olefins with diselenides and alcohols in the presence of hydrogen peroxide/air oxidant: an efficient access to <Emphasis Type="Italic">α</Emphasis>-alkoxyl selenides

Under iodine-catalyzed and visible light-irradiated aerobic conditions, selenoalkoxylation of olefins with diselenides and alcohols can be efficiently achieved to afford the useful α-alkoxyl selenides in the presence of only 0.5 equiv. of H₂O₂. Controlling the sub-stoichiometric H₂O₂ amount is crucial to avoid the non-selective over-oxidation of the diselenides that leads to the ineffective hyper-valent selenium compounds. Meanwhile, under visible light irradiation, the green, safe, and low-cost air can work as a supplemental mild oxidant in the reaction to ensure selective oxidation of the diselenides, full conversion of the reactants, and ultimately good yield of the products.     

Iridium‐Catalyzed ortho‐Arylation of Benzoic Acids with Arenediazonium Salts

In the presence of catalytic [{IrCp*Cl₂}₂] and Ag₂CO₃, Li₂CO₃ as the base, and acetone as the solvent, benzoic acids react with arenediazonium salts to give the corresponding diaryl‐2‐carboxylates under mild conditions. This C? H arylation process is generally applicable to diversely substituted substrates, ranging from extremely electron‐rich to electron‐poor derivatives. The carboxylate directing group is widely available and can be removed tracelessly or employed for further derivatization. Orthogonality to halide‐based cross‐couplings is achieved by the use of diazonium salts, which can be coupled even in the presence of iodo substituents.     

Reductive cleavage of the Se–Se bond in diselenides by the Sm/HgCl2 system: Formation and reactions of samarium selenolates

Treatment of diaryl diselenides and dialkyl diselenides with metallic samarium and mercury (II) chloride in tetrahydrofuran conveniently gave samarium arylselenolates and alkylselenolates. These “living” species reacted with acyl chlorides, acid anhydrides, methyl chloroformate, organic halides, epoxides, α,β‐unsaturated esters, and an α,β‐unsaturated nitrile to afford selenoesters, selenoformates, and unsymmetrical selenides in good yields under mild and neutral condition. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 203–208, 1999