Ruthenium-indenylidene complexes: Scope in cross-metathesis transformations

A comparative study examining the catalytic activity of a series of five indenylidene-containing ruthenium complexes in olefin cross-metathesis reactions is presented. Results reveal the greater efficiency of precatalyst 5, highlighting the key role of the N,N’-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr) ligand for this transformation. The scope of this precatalyst was investigated and several microwave experiments were carried out allowing for catalyst loadings as low as 0.1 mol%. Overall, cross-metathesis products were isolated in moderate to excellent yields with high stereoselectivity.