An efficient and green microwave-assisted heterogeneous S-arylation protocol, reported for the first time, provided excellent coupling conversions and selectivities in minutes of reaction using Fe (homocoupling) and Cu (cross-coupling) supported metal nanoparticles.

A library of ten 1,3-diyne-linked peptoids has been synthesized through an Ugi four-component reaction (U-4CR) followed by a copper-catalysed alkyne homocoupling (Glaser reaction). The short and chemoselective reaction sequence allows generating diverse (pseudo) dimeric peptoids. A combinatorial version allows the one-pot preparation of, e.g., six-compound-libraries of homo- and heterodimers ve...

A novel silver(I)-fluoride-mediated homocoupling reaction of β,β-difluorostyrene derivatives is described. The transformation is initiated via nucleophilic addition of silver(I) fluoride to β,β-difluorostyrenes, which is followed by dimerization of the corresponding benzylsilver intermediates. The reaction shows good substrate scope, functional group tolerance, and represents the first report o...

Carbon-nitrogen (C-N) bond-forming reactions of amines with aryl halides to generate arylamines (anilines), mediated by a stoichiometric copper reagent at elevated temperature (>180°C), were first described by Ullmann in 1903. In the intervening century, this and related C-N bond-forming processes have emerged as powerful tools for organic synthesis. Here, we report that Ullmann C-N coupling ca...

Chloromethylgold(I) complexes of phosphine, phosphite, and N-heterocyclic carbene ligands are easily synthesized by reaction of trimethylsilyldiazomethane with the corresponding gold chloride precursors. Activation of these gold(I) carbenoids with a variety of chloride scavengers promotes reactivity typical of metallocarbenes in solution, namely homocoupling to ethylene, olefin cyclopropanation...

A novel pathway for the homocoupling reaction has been achieved using a similar protocol as the cross-coupling reaction. Ethyl bromoacetate is chosen to initiate the coupling reaction through oxidative addition to a Pd(0) species, and an PdBr(enolate) intermediate is formed. This intermediate can undergo double transmetalation with an alkynyl copper reagent, and reductive elimination produces a...

The copper-mediated aromatic nucleophilic substitution reactions developed by Fritz Ullmann and Irma Goldberg required stoichiometric amounts of copper and very high reaction temperatures. Recently, it was found that addition of relatively cheap ligands (diamines, aminoalcohols, diketones, diols) made these reactions truly catalytic, with catalyst amounts as low as 1 mol% or even lower. Since t...

The Ullmann-type coupling reaction of vinyl bromides and imidazoles in ILs at 90-110 degrees C gave the corresponding N-vinylimidazoles in good to excellent yields by using L-proline as the ligand; the double bond geometry of the vinyl bromides was retained under the reaction conditions.