Olefin metathesis catalyst: Stabilization effect of backbone substitutions of N-heterocyclic carbene

Ruthenium olefin metathesis catalysts bearing an N-phenyl-substituted N-heterocyclic carbene (NHC) ligand that are resistant to decomposition through C-H activation have been prepared and tested in ring closing metathesis (RCM), cross metathesis (CM), and ROMP reactions. The N,N '-diphenyl-substituted NHC complex proved to be one of the most efficient catalysts in RCM to form tetrasubstituted olefins.