The nature of the preferred chain-carrying metallacarbene intermediate in metathesis reactions involving alk-1-enes

Abstract

The minor products from the cross-metathesis of norbornadiene (NBD) with hex-1-ene and of cyclopentene (CP) with octa-1,7-diene (1,7-OD), respectively, show that the complexed alkylidenes; RCH[Mt](where [Mt] denotes the metal site with the ligands attached), are much preferred to the complexed methylene, CH₂[Mt], as chain carriers formed by the reactions of the terminal olefins; but CH₂[Mt], when formed, is highly reactive towards the latter, with the strongly electrophilic methylene ligand selectively adding to the terminal olefins at the C-1 position.