Evaluation of an olefin metathesis pre-catalyst with a bulky and electron-rich N-heterocyclic carbene

SPN thanks the European Research Council(227817) (Advanced Investigator Award ‘FUNCAT’), the EU(CP-FP 211468) (Seventh Framework Programme Project ‘EUMET’), and the Engineering and Physical Sciences Research Council for funding. SPN is a Royal Society Wolfson Merit Award holder. AP thanks the Spanish MINECO for a Ramón y Cajal contract (RYC-2009-05226) and European Commission for a Career Integration Grant (CIG09-GA-2011-293900). The commercially-available metathesis pre-catalyst M23 has been evaluated alongside new complex [RuCl2((3-phenyl)indenylidene)(PPh3)(SIPrOMe)] (1), which bears a para-methoxy-substituted N-heterocyclic carbene ligand. Several model metathesis reactions could be conducted using only parts-per-million levels of ruthenium catalyst. The effects of the different NHC ligands on reactivity have been explored. Postprint