Both the vinyl insertion polymerization (VIP) of olefins [1–7] and the ring-opening metathesis polymerization (ROMP)[8, 9] of cyclic olefins are well-established polymerization techniques based on the insertion of a monomer between a transition metal (ion) and a growing polymer chain. In fact, they are related to each other, since a cationic, VIP-active catalyst may be converted into a ROMP-active catalyst by a simple α-elimination process. In ...
