Abstract: Ruthenium carbene complexes of the type (PPh& (X) 2Ru= CH-CH= CPh2(1, X= C1; 2, X= CF3COO) can react with strained acyclic olefins and functionalized olefins. Complex 1 reacts with methylenecyclopropane and methylenecyclobutane and their derivatives to generate new active ring-opening metathesis polymerization (ROMP) catalysts. The product from the reaction between 1 and ethyl vinyl ether decomposes ...