Indium-mediated cleavage of diphenyl diselenide and diphenyl disulfide: efficient one-pot synthesis of unsymmetrical diorganyl selenides, sulfides, and selenoesters

A convenient and efficient method was developed for the synthesis of alkyl phenyl selenides, sulfides, and selenoesters in one-pot reaction by using indium metal. The reaction showed the selectivity for tert-alkyl, benzylic, and allylic halides over primary and secondary alkyl halides. For the reaction of primary and secondary alkyl iodides and bromides, the yields of selenides were improved by the addition of a catalytic amount of iodine.     

Indium(I) iodide-mediated cleavage of diphenyl diselenide. An efficient one-pot procedure for the synthesis of unsymmetrical diorganyl selenides

A simple and efficient procedure has been developed for the synthesis of unsymmetrical diorganyl selenides through a one-pot indium(I) iodide-mediated reaction of alkyl halide and diphenyl diselenide in methylene chloride at room temperature. [reaction: see text]     

Ionic liquid/PPh3 promoted cleavage of diphenyl disulfide and diselenide: a straight-forward metal-free one-pot route to the synthesis of unsymmetrical sulfides and selenides

A metal-free cleavage of diphenyl disulfide and diphenyl diselenide has been achieved using ionic liquid/triphenyl phosphine (PPh₃) and a convenient protocol for the one-pot synthesis of unsymmetrical sulfides and selenides by condensing ‘in situ’ generated thiolate or selenate anion with alkyl halides has been developed. In addition, 1,4-conjugate addition of the generated thiolate anions to activated alkenes has also been demonstrated. The ionic liquid, 1-methyl-3-pentyl imidazolium bromide, [pmIm]Br plays a crucial role in promoting the course of the reactions and shows superior activity and selectivity compared to other solvents. The [pmIm]Br has been reused for at least five times without appreciable loss of activity.     

Indium(I) iodide-promoted cleavage of diaryl diselenides and disulfides and subsequent condensation with alkyl or acyl halides. One-pot efficient synthesis of diorganyl selenides, sulfides, selenoesters, and thioesters

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.     

Improved synthesis of aryltriethoxysilanes via palladium(0)-catalyzed silylation of aryl iodides and bromides with triethoxysilane.

The scope of the palladium-catalyzed silylation of aryl halides with triethoxysilane has been expanded to include aryl bromides. A more general Pd(0) catalyst/ligand system has been developed that activates bromides and iodides: palladium(0) dibenzylideneacetone (Pd(dba)(2)) is activated with 2-(di-tert-butylphosphino)biphenyl (Buchwald's ligand) (1:2 mol ratio of Pd/phosphine). Electron-rich para- and meta-substituted aryl halides (including unprotected aniline and phenol derivatives) undergo silylation to form the corresponding aryltriethoxysilane in fair to excellent yield; however, ortho-substituted aryl halides failed to be silylated.     

Indium(I) iodide promoted cleavage of dialkyl/diaryl disulfides and subsequent anti-Markovnikov addition to styrenes: a new route to linear thioethers

The reaction of thiolate anions, generated in situ by indium(I) iodide promoted cleavage of dialkyl/diaryl disulfides, with styrenes has been investigated. Thiolate anions add to a variety of styrenes in an anti-Markovnikov manner producing linear thioethers in high yields. This method provides a new route to the synthesis of thioethers.     

Hydrothiolation of terminal alkynes with diaryl disulfides and diphenyl diselenide: selective synthesis of (Z)-1-alkenyl sulfides and selenides

A simple, stereoselective and efficient method for the hydrothiolation of terminal alkynes with diaryl disulfides and diphenyl diselenide has been developed. In the presence of CuI, rongalite, and Cs₂CO₃, a variety of disulfides underwent the reaction of terminal alkynes stereoselectively to afford the corresponding (Z)-1-alkenyl sulfides in moderate to excellent yields. It is noteworthy that hydroselenations of 1,2-diphenyldiselane with alkynes are also conducted smoothly to afford (Z)-1-alkenyl selenides in good yields under the standard conditions.     

A highly regioselective bisselenation of allenes with diphenyl diselenide catalyzed by tetrakis(triphenylphosphine)palladium(0)

Tetrakis(triphenylphosphine)palladium(0) acts as an effective catalyst for highly regioselective bisselenation of allenes with diphenyl diselenide.     

A one-pot synthesis of bisarylhydrazones by Cu(I)-catalyzed aerobic oxidation

An efficient Cu(I)-catalyzed one-pot synthesis of N-substituted (or NH) bisarylhydrazones is reported. A further cyclization reaction could occur towards the synthesis of benzimidazoles or triazoles with elevated temperature. A plausible alkylation–oxidation–alkylation mechanism is proposed based on experimental results and literature.     

A novel palladium(0)-catalyzed addition of diphenyl disulfide to allenes leading to vicinal disulfides and its application to carbonylation with carbon monoxide

Tetrakis(triphenylphosphine)palladium(0) catalyzes a highly regioselective bisthiolation of terminal allenes with diphenyl disulfide to afford the corresponding 2-(phenylthio)-substituted allyl sulfides in good yields. In addition, this reaction system can be applied to the carbonylation under pressurized carbon monoxide.     

A one-pot synthesis of constitutionally unsymmetrical rotaxanes using sequential Cu(I)-catalyzed azide-alkyne cycloadditions

A one-pot sequential Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) strategy is presented for the synthesis of constitutionally unsymmetrical cyclobis(paraquat-p-phenylene)-based rotaxanes in good yields from simple starting materials. The methodology consists of performing multiple CuAAC reactions to stopper a pseudorotaxane in a stepwise manner, the order of which is controlled through silyl-protection and Ag(I)-catalyzed deprotection of a terminal alkyne. The methodology is highlighted by the synthesis of an amphiphilic branched [4]rotaxane. The methodology increases the ability to access ever more complicated mechanically interlocked compounds to serve in devices as sophisticated and functional molecular machinery.     

Na/THF- Mediated cleavage of organic disulfides/diselenides. An efficient and one-pot regioselective method to the synthesis of β-hydroxy sulfides/selenides

A new, facile, and efficient methodology for synthesizing β-hydroxy sulfides/selenides has been reported. In this study, 1,2-epoxide ring opening was used as the synthetic protocol, and this reaction was examined using metallic sodium with no additional catalyst. This lead to the synthesis of the desired ring-opened products. Relatively short reaction times, mild reaction conditions, a simple work-up, moderate to good yields of products, and remarkable regioselectivity of the nucleophilic attack were other important features of this study.     

I(-)-catalyzed methyl-oxygen bond cleavage in 2-methoxyfurans. An efficient synthesis of butenolides

An efficient I(-)-catalyzed methyl-oxygen bond cleavage in 2-methoxyfurans was observed. The subsequent C-C bond formation occurred at the 5-position to afford substituted butenolides. The structures of the final products were determined by the X-ray diffraction study.     

Ruthenium(III) chloride catalyzed efficient synthesis of unsymmetrical diorganyl selenides via cleavage of dibenzyl and diphenyl diselenides in the presence of zinc

[equation: see text] An efficient one-pot route to unsymmetrical diorganyl selenides has been developed by ruthenium(III) chloride catalyzed reactions of dibenzyl or diphenyl diselenides with alkyl halides in the presence of zinc. Organic iodides, bromides, and activated chlorides underwent the reactions efficiently. Unreactive organic chlorides also underwent the same type of selenation with sodium bromide as the additive.     

Cu(I)-catalyzed one-pot synthesis of 1,4-disubstituted 1,2,3-triazoles via nucleophilic displacement and 1,3-dipolar cycloaddition

An efficient method is described for the regioselective synthesis of 1,4-disubstituted 1,2,3-triazoles in high yields from a variety of Baylis-Hillman acetates and terminal alkynes with sodium azide using CuI as a catalyst, in either water or polyethylene glycol (PEG). This procedure is operationally simple and environmentally benign. Polyethylene glycol (PEG) serves as an efficient reusable solvent with higher efficiency.     

Stereodivergent synthesis of chiral 2-alkenylaziridines: palladium(0)-catalyzed 2,3-cis-selective aziridination and base-mediated 2,3-trans-selective aziridination

Whereas treatment of the allylic mesylates of N-protected 2-alkyl-4-amino-(E)-2-alken-1-ols with sodium hydride in DMF yields exclusively the corresponding thermodynamically less stable 2,3-trans-2-alkenyl-3-alkylaziridines, exposure of the methyl carbonates of N-protected 2-alkyl-4-amino-(E)-2-alken-1-ols to a catalytic amount of Pd(PPh(3))(4) in THF or 1,4-dioxane affords predominantly the corresponding thermodynamically more stable 2,3-cis-2-alkenyl-3-alkylaziridines. The kinetically favored trans-selective aziridination would be attributed to the allylic 1,3-strain in aza-anionic intermediates. The conformational analysis of the sterically highly congested 2-alkenylaziridines thus obtained is also presented.     

A Cu(I)-catalyzed C-H alpha-amination of esters. Direct synthesis of hydantoins

This paper describes a novel intermolecular alpha-amination process of esters using CuCl as catalyst and di-tert-butyldiaziridinone as nitrogen source. A variety of hydantoins can be formed effectively under mild reaction conditions.     

A novel entry to functionalized benzofurans and indoles via palladium(0)-catalyzed arylative dearomatization of furans

A novel entry to functionalized benzofurans and indoles from furans in moderate to good yields has been developed. This protocol involves palladium(0)-catalyzed dearomatizing intramolecular arylation of the furan ring, formation of a π-allylic palladium complex, furan ring opening, and a β-hydride elimination sequence.     

Umpolung of chiral 2-ethynylaziridines: Indium(I)-mediated stereoselective synthesis of nonracemic 1,3-amino alcohols bearing three chiral centers, catalyzed by palladium(0)

Treatment of 3-alkyl-2-ethynylaziridines with InI in the presence of Pd(PPh(3))(4) and H(2)O gave allenylindium reagents bearing a protected amino group in high yields. Stereoselective addition of the allenylindium to aldehydes affords 2-ethynyl-1,3-amino alcohols bearing three chiral centers in good yields.