Vinylogous Anionic Ring-Opening Polymerization of Vinylidenecyclopropanes with Native C-H Bonds as the Dormant...

Since its inception in 2023, the concept of "C-H bonds as the dormant species" to control chain growth has emerged as a promising, though still evolving, strategy for precision polymer synthesis. Beyond offering a simpler polymerization method, this concept is expected to promote unprecedented reaction pathways. In this study, we report the first vinylogous anionic ring-opening polymerization (ROP) of vinylidenecyclopropanes. Cooperative La(OTf)₃/DBU catalysis, in conjunction with various sp³ and sp² C-H bonds, has streamlined the synthesis of well-defined alkyne polymers, which are amenable to further chemical modifications. Control experiments and density functional theory (DFT) calculations provide insights into the origin of selectivity and the role of dormant C-H bonds in the reversible-deactivation equilibrium.