On the Structure of Intermediates in Enyne Gold(I)‐Catalyzed Cyclizations: Formation of trans‐Fused Bicyclo[5.1.0]octanes as a Case Study

The nature of cyclopropyl gold(I) carbene‐type intermediates has been reexamined as part of a mechanistic study on the formation of  cis ‐ or  trans ‐fused bicyclo[5.1.0]octanes in a gold(I)‐catalyzed cascade reaction. Benchmark of DFT methods together with QTAIM theory and NBO analysis confirms the formation of distinct intermediates with carbenic or carbocationic structures in the cycloisomerizations of 1,6‐enynes.