Dinuclear thiazolylidene copper complex as highly active catalyst for azid–alkyne cycloadditions

Abstract

SummaryA dinuclear N-heterocyclic carbene (NHC) copper complex efficiently catalyzes azide–alkyne cycloaddition (CuAAC) “click” reactions. The ancillary ligand comprises two 4,5-dimethyl-1,3-thiazol-2-ylidene units and an ethylene linker. The three-step preparation of the complex from commercially available starting compounds is more straightforward and cost-efficient than that of the previously described 1,2,4-triazol-5-ylidene derivatives. Kinetic experiments revealed its high catalytic CuAAC activity in organic solvents at room temperature. The activity increases upon addition of acetic acid, particularly for more acidic alkyne substrates. The modular catalyst design renders possible the exchange of N-heterocyclic carbene, linker, sacrificial ligand, and counter ion.

Side-Arm Functionalized Silylene Copper(I) Complexes in Catalysis

“…Putting Click chemistry in simple terms, any Cu­(I) source can be used as a catalyst; however, well-designed Cu­(I) complexes can increase the selectivity, decrease catalyst loadings, or establish milder reaction conditions. − When Fokin and Finn revealed crucial details of the CuAAC mechanism in 2005 and therefore the mandatory role of copper­(I), following studies increasingly concentrated on dinuclear copper species as the active species and illustrated their potential. ,,,, …”

Synthesis of the First Resorcin[4]arene-Functionalized Triazolium Salts and Their Use in Suzuki–Miyaura Cross-Coupling Reactions

“…Their precursors, namely 1,2,3-triazoles, are easily accessible through copper-catalyzed Huisgen [3 + 2] click-type cycloaddition of azides and alkynes (CuAAC) [6,7], followed by N3-quaternarization. The resulting 1,2,3-triazolium salts can then be converted to transition metal complexes that, i.a., are suitable for Suzuki-Miyaura [8][9][10][11][12][13][14][15][16][17][18], Mizoroki-Heck [19,20], and Sonogashira coupling reactions [19,21], as well as for various reduction or oxidation reactions [22][23][24][25][26][27], and C-heteroatom bond forming reactions [28][29][30][31][32].…”

“…], as well as for various reduction or oxidation reactions [22][23][24][25][26][27], and C-heteroatom b ng reactions [28][29][30][31][32].…”

Photocatalytic copper-catalyzed azide–alkyne cycloaddition click reaction with Cu(ii) coordination polymer

“…Such as the copper halide compounds, some improved Cu(I)-organic complexes, simple Cu(II) salts together with reducing agents and nano-structured solid catalysts. [8][9][10][11][12][13][14][15] However, the oxide species existing in the reaction system will inuence the effect of Cu(I) catalysts and homogeneous catalytic systems are inconvenient with regards to the separation and purication of the product. As we all know, although copper is an essential element for humans, large and acute doses can have harmful, even fatal, effects.…”