Olefin metathesis is an exceptionally versatile methodology for the catalytic assembly of carbon-carbon bonds. Long embraced by synthetic chemists in discovery operations in academia and industry, molecular metathesis catalysts are now beginning to see uptake in ambitious applications: in process chemistry in pharma, in chemical biology, and in the valorization of renewable feedstocks and plastic wastes (Figure 1a). This is a welcome development, as metathesis has tremendous potential to reduce the environmental footprint associated with chemical and pharmaceutical manufacturing. However, these demanding contexts reveal major limitations arising from short catalyst lifetimes.
The pathways by which the important ruthenium catalysts deactivate or decompose are now coming into focus. We believe that such understanding is key to designing better processes and, ultimately, better catalysts. Insights will be described into the operation and decomposition of key metathesis catalysts, including the most recent generation of high-performing catalysts (Figure 1b). These will be tied to key challenges and new opportunities relating to catalyst design, synthesis, and deployment. More broadly, these studies highlight the importance of understanding catalysis decomposition, a little-explored frontier in molecular catalysis.
Figure 1. (a) Advanced applications of olefin metathesis in pharmaceutical and sustainable synthesis. (b) Key metathesis catalysts.