How Does Ring-Closing Metathesis (RCM) Help Build Complex Cyclic Molecules?

At Apeiron, we specialize in advanced synthetic strategies that unlock the full potential of molecular design. One of the most powerful tools in our toolkit is ring-closing metathesis (RCM) — a transformative reaction that enables the efficient formation of cyclic and macrocyclic molecules, including high-value compounds like musks, bioactive natural products, and pharmaceutical scaffolds.

What Is Ring-Closing Metathesis?

Ring-closing metathesis is a type of olefin metathesis reaction in which a linear molecule bearing two terminal alkenes reacts to form a new carbon–carbon double bond, effectively "closing the ring." Catalyzed by well-defined ruthenium-based catalysts (such as UltraCat and UltraNitroCat), RCM has revolutionized the synthesis of macrocyclic structures, offering cleaner reactions, fewer steps, and high atom economy.

Why Is RCM Ideal for Macrocyclization?

RCM is particularly well-suited for macrocyclization, the process of forming large ring systems (typically 12 atoms or more). Traditional macrocyclization routes often suffer from low yields and side reactions due to entropic and enthalpic challenges. In contrast, RCM facilitates ring formation under mild conditions and with remarkable functional group tolerance.
This makes it especially attractive for the synthesis of:

• Fragrance compounds like macrocyclic musks, prized for their long-lasting scent profiles.
• Cyclic peptides and depsipeptides, relevant in drug discovery.
• Macrocyclic drug candidates, known for their target specificity and bioavailability.

Applications in Fragrance and Beyond

At Apeiron, we leverage ring-closing metathesis not only in pharmaceutical R&D but also in fine chemicals, particularly in the production of musks. These high-value compounds benefit from the precision and efficiency RCM offers, enabling scalable routes to otherwise difficult-to-access macrocycles.

Why Choose Apeiron?

Our team at Apeiron brings deep expertise in metathesis chemistry, offering custom synthesis, route scouting, and scale-up solutions for partners in pharmaceuticals, fragrances, and advanced materials. Whether you're developing a macrocyclic drug, designing a new musk fragrance, or exploring complex ring systems, we can help bring your ideas to life through the strategic application of RCM and macrocyclization.