A method is provided of forming an olefin from a first olefin and a second olefin in a metathesis reaction, comprising reacting the first olefin with the second olefin in the presence of a compound that catalyzes the metathesis reaction such that the molar ratio of the compound to the first or the second olefin is from 1:500 or less, and the conversion of the first or the second olefin to the olefin is at least 30%.