barbaralyl

Intramolecular cyclopropanation of a gold(I) carbene can lead to very complex structures starting from 7-alkynylcyclohepta-1,3,5-trienes 95 (Scheme 25 ). 116 This reaction generates highly fluxional barbaralyl gold(I) cations 96 that can be trapped by the pending alkene to form 97a, b, which are in equilibrium by Cope rearrangement both in the solid state and in solution.