Relative rate profile for ring-closing metathesis of a series of 1-substituted 1,7-octadienes as promoted by a 4,5-dihydroimidazol-2-ylidene-coordinated ruthenium catalyst

[reaction: see text] This report details the kinetic responses of nine compounds of type 6 to ring-closing metathesis as promoted by 2 to give the identical product 7. The experimental observations have been subjected to Hammett analysis. The rho value for the composite aromatic derivatives (R = p-XC(6)H(4)-) differs from that of the aliphatic series, although both are negative because electron-donating groups accelerate the reaction.