Mo-based1 and Ru-based2 complexes are regularly used to catalyze a range of ring- forming or ring-opening processes. 3 Mocatalyzed reactions that give rise to macrocyclic trisubstituted olefins, 4 and Ru-based catalysts that effect the formation of disubstituted olefins within large rings, 5 have been employed to fabricate an impressive array of complex molecules. In most instances, without catalytic ring-closing metathesis (RCM), such ...