“…Subsequently, another groundbreaking result was reported by Buchmeiser and co-workers, who demonstrated the first example of CP using easy-to-use, modified Grubbs catalysts containing electron-withdrawing ligands, such as the trifluoroacetate ligand, and showed that these catalysts produced conjugated polyenes with five-membered ring repeat units exclusively via α-addition. , Recently, our group reported a highly efficient living CP of 1,6-heptadiyne derivatives using third-generation Grubbs catalyst to produce conjugated polyenes with exclusive five-membered ring backbones with excellent molecular weight control and narrow polydispersity index (PDI) . With this catalyst, the syntheses of fully conjugated block copolymers and other functional polyenes were also possible. − However, the formation of conjugated polyenes with six-membered rings by selective β-addition using Ru catalysts has not been achieved. Instead, Ru catalysts could only produce polyenes with six-membered rings from various 1,7-octadiyne monomers by selective α-addition .…”