Ruthenium carbene complexes of the type (PPh(3))(2)(X)(2)Ru=CH-CH=CPh(2) (1, X = Cl; 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 through a bimolecular coupling pathway, Complex 2 reacts with functionalized terminal olefins, such as alkyl vinyl ether, enamine, and alkyl vinyl sulfide to give hetero-substituted carbene complexes. However, in the case of alkyl vinyl ether, the resulting alkoxymethylenecarbene complex decomposes to ruthenium carbonyl species at room temperature. Complex 2 can also isomerize allylic vinyl ether or alcohol. Aromatic amines can react with 2 by first coordinating trans to the carbene ligand; a fact which indicates that the potential coordination site for olefin metathesis may be trans to the carbene moiety. The reactivity pattern of 2 with functionalized vinyl olefins suggests that this reaction is best understood under the context of a Lewis acid/Lewis base interaction.