When well-defined olefin metathesis catalysts started to come on scene, the majority of initial interest was in ring opening metathesis polymerization (ROMP), and subsequently ring closing metathesis (RCM). Cross metathesis (CM) remained a niche application until somewhat later. I can’t help but think that the reluctance of the community to embrace CM is due in part to the perception that it’s an equilibrium process from which you always get mixtures.
The work of Arnab Chatterjee in the Grubbs group helped to change this perception. The 2003 Grubbs JACS paper didn’t have a ton of new chemistry in it but was important because it outlined a paradigm that made practical CM accessible to the masses. CM reactions were broken down by substrate type and catalyst, and a predictive model was put forth for designing selective CM reactions.
The ideas in this article may seem obvious after you’ve been working with cross metathesis for a while, but it’s the place to start for all future CM users.