Gold carbenes via 1,2-dialkoxycyclopropane ring-opening: a mass spectrometric and DFT study of the reaction pathways.

We report experimental and computational evidence that cationic N-heterocyclic carbene gold complexes with electron-rich cyclopropanes rearrange to produce Fischer gold carbene complexes in the gas phase, in analogy to long-known condensed-phase rearrangements of protonated cyclopropanes. Our results help to generalize the relationship between Lewis-acidic metal complexes of cyclopropanes, metallacyclobutanes and metal carbenes.