Formation of Isomerized E,Z-Configured 1,3-Dienes in Construction of Macrocyclic Trienes by Diene-Ene RCM

Construction of macrocyclic trienes by diene-ene RCM of tetraenes was examined. In the reactions, macrocyclic trienes were obtained as a mixture of two isomers with E,Z-configured 1,3-diene moiety. The formation of two isomers can be understandable by the E-Z isomerization of the initially generated ruthenium alkenyl carbene intermediate.