52826-45-6Relevant articles and documents
Cationic Copper Iminophosphorane Complexes as CuAAC Catalysts: A Mechanistic Study
Korstanje, Ties J.,Oudsen, Jean-Pierre H.,Tromp, Moniek,Van Der Vlugt, Jarl Ivar,Venderbosch, Bas
supporting information, p. 3480 - 3489 (2020/11/02)
We have combined Cu K-edge X-ray absorption spectroscopy with NMR spectroscopy (1H and 31P) to study the Cu-catalyzed azide-alkyne cycloaddition (CuAAC) reaction under operando conditions. A variety of novel, well-defined CuI iminophosphorane complexes were prepared. These ligands, based on the in situ Staudinger reduction when [Cu(PPh3)3Br] is employed, were found to be active catalysts in the CuAAC reaction. Here, we highlight recent advances in mechanistic understanding of the CuAAC reaction using spectroscopic and kinetic investigations under strict air-free and operando conditions. A mononuclear Cu triazolide intermediate is identified to be the resting state during catalysis; cyclization and protonation both have an effect on the rate of the reaction. A key finding of this study includes a novel group of highly modular CuI complexes that are active in the base-free CuAAC reaction.
Chemoselectivity in coupling of azides with thioacids in solution-phase and solvent-free conditions
Nagarajan, Sangaraiah,Shanmugavelan, Poovan,Sathishkumar, Murugan,Priyadharshini, Namachivayam,Sudakar, Padmanaban,Ponnuswamy, Alagusundaram
, p. 668 - 680 (2013/01/15)
Solvent-free rapid coupling of monothiocarboxylic acid with azide affords carboxamide chemoselectively. Triphenyl phosphine included as an additive influences the chemoselectivity, yielding carboxamide and thioamide. Similar variation in the chemoselectivity is observed in the absence and presence of triphenyl phosphine in solution-phase methodology. Rapidity and ecofriendliness of the solvent-free approach to yield the products in just 15min is noteworthy compared to the solution-phase protocol, which has a long reaction time (1-3 days).
Organophosphorus-catalysed Staudinger reduction
Van Kalkeren, Henri A.,Bruins, Jorick J.,Rutjes, Floris P. J. T.,Van Delft, Floris L.
supporting information; experimental part, p. 1417 - 1421 (2012/07/03)
The first Staudinger reduction that is catalytic in phosphine has been developed, showing excellent yields and functional group selectivity. To this end we utilised dibenzophosphole catalysts and mild in situ reduction of the intermediate iminophosphoranes. We could avoid the necessity of water during the reduction, obtained no phosphine oxides as waste and thus enabled facile purification of the product. A range of azides was converted into amines with good to excellent yields and high functional group tolerance. Copyright