Allylruthenium( IV ) Complexes as Highly Efficient ROMP Catalysts

First activate, then polymerize. This is the way that ruthenium complexes such as 1 can be used to catalyze the ring-opening metathesis polymerization efficiently. Diazoalkanes serve as activating agents and depending on their substitution pattern subequivalent or excess amounts are required. When ethyl diazoacetate is used, turnover frequency values above 105 h−1 have been achieved in the ring-opening metathesis polymerization of norbornene.