Cyclopropenylgold(I) Complexes as Aurated Carbenoids or Quasi‐Carbenes

Abstract 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 (E a 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