Aryl- or styrylcycloheptatrienes undergo retro-Buchner reactions with cationic gold(I) complexes such as [2-PhC6H4(Me3C)2PAuN≡CMe]+.bul.SbF6- to generate gold carbene complexes which cyclopropanate olefins such as trans-stilbene to give di- and trisubstituted cyclopropanes in 39-91% yields and in most cases stereoselectively.
![Cyclopropanation with gold(I) carbenes by retro-Buchner reaction from cycloheptatrienes](https://www.iciq.org/wp-content/uploads/2014/03/Cyclopropanation-with-goldI_11952.gif)