Challenges in olefin metathesis: past, present and future

Olefin metathesis has become a cornerstone in modern synthetic chemistry, enabling diverse applications across organic synthesis, polymer science, and industrial processes. Despite its transformative impact, significant challenges persist, including catalyst stability, functional group tolerance, selectivity, and scalability. Ruthenium-based catalysts dominate the field, yet their sensitivity to oxygen, moisture, and harsh conditions limits industrial applicability. Functional group incompatibility and the difficulty in achieving precise product selectivity further hinder its versatility, particularly in cross-metathesis (CM) and ring-closing metathesis (RCM). Advances in catalyst recycling, green chemistry practices, and alternative systems using earth-abundant metals like iron are promising but remain underdeveloped. Expanding substrate scope, improving mechanistic understanding, and integrating metathesis with other catalytic processes offer opportunities for innovation. Addressing these issues through predictive catalysis, novel ligand design, and artificial intelligence-driven insights will enhance the sustainability and efficiency of metathesis, cementing its role as a pivotal reaction in future chemical synthesis. • Olefin Metathesis is key in modern synthesis, supporting green chemistry in organic, polymer, and industrial applications. • Ruthenium catalysts dominate, but issues such as stability, functional group tolerance, and decomposition limit efficiency and scalability. • Advances in catalyst design, such as CAAC ligands, have improved Z-selectivity in cross-metathesis reactions. • Research is focused on developing more sustainable, earth-abundant metal catalysts like iron and manganese. • Achieving precise control in CM reactions remains a significant challenge, necessitating tailored catalyst structures.