p-cymene as a solvent for olefin metathesis: matching efficiency and sustainability.

The underexploited, biorenewable, p-cymene is employed as a solvent for the metathesis of various substrates. p-cymene is a nontoxic compound that can be obtained in large amounts from side product of cellulose and citrus industry. For the cross-metathesis of estragole with methyl acrylate, this solvent prevents the consecutive double-bond isomerization of the product and gives the best yield of all solvents tested. Undesired consecutive isomerization is a major problem for many substrates in olefin metathesis, including pharmaceutical precursors, and the use of p-cymene as solvent may be a way to prevent it. This solvent presented a better performance for metathesis than toluene for three substrates tested in this work, matching its performance for other two substrates.