While gold‐mediated synergistic catalytic processes involving transmetalations with other metals are well understood, AuI/AuIII cycles in these reactions are rarely reported. Herein a gold‐catalyzed direct alkynylation of cyclopropenes is enabled by two operating catalytic cycles, an oxidative catalytic cycle involving an alkynyl AuIII complex formed by oxidative addition and one involving a silver‐mediated C−H activation.

Gold(I) complexes are considered active species toward oxidative addition; current understanding indicates a different mechanism in contrast to other late transition metals, but a rational understanding of the reactivity profile is lacking. Herein, we propose that the accessibility of the gold(I) center to tri-or tetracoordination is critical in the oxidative process involving a tri-or tetra-coordinate gold(I) with the oxidizing reagent as one of the ligands as an intermediate. A computational study of the geometry of (Phen)R 3 PAu(I)NTf 2 complexes shows that the accessibility of such tricoordinate species shows a good correlation with the "trans influence" of phosphine ligands: the weak σ-donating phosphine ligands promote tricoordination of gold(I) complexes. The oxidative addition to the asymmetric tricoordinate (Phen)R 3 PAu(I)NTf 2 complexes with alkynyl hypervalent iodine reagents was built. The kinetic profile of the oxidative addition exhibits a good relationship to the Hammett substituent parameter (ρ = 3.75, R 2 = 0.934), in which the gold(I) complexes bearing less σ-donating phosphine ligands increase the rate of oxidative addition. The positive ρ indicates a high sensitivity of the oxidative addition to the trans influence. The reactivity profile of oxidative addition to a linear bis(pyridine)gold(I) complex further supports that the oxidative addition to gold(I) complexes is promoted by ligands with small trans influence.

Highly strained hydrocarbons have always been a research target of high interest. Due to their untypical electronic structure, they show interesting reactivity patterns and can easily be activated by π‐coordination to or insertion reactions with metal complexes. Herein we report the synthesis of a range of 3,3‐disubstituted cyclopropenylgold(I) complexes. The synthesis of such compounds with a metal, which usually easily activate cyclopropenes is a double‐edged sword. We found σ‐bound vinylic gold to generally have a strong stabilizing effect in terms of ring strain. The complexes show a strong distortion, preactivating the cyclopropenyls towards the ring‐opening mode which thermally generates 1‐aurated vinylcarbenes which is reflected by a much faster conversion (Ea of 10 kcal/mol instead of 40 kcal/mol, the reaction proceeds at temperatures as low as −20 °C instead of 200 °C reported in the literature). In 3‐phenyl‐cyclopropenyl complexes, these could be trapped intramolecularly to give indenylgold(I) complexes. The properties of these highly strained complexes were investigated, utilizing a range of analytical and experimental procedures and Kohn‐Sham density functional theoretic methods.magnified image

Using 2-methyl THF as solvent enables efficient and ultrafast amidation of esters by lithium amides at room temperature in air, edging closer towards reaching air- and moisture-compatible polar organometallic chemistry.