Metathesis

Olefin metathesis is an organic reaction that involves the rearrangement of carbon-carbon double bonds by redistributing alkene fragments. This reaction has revolutionized organic synthesis by revealing new disconnections, opening up opportunities for advancements in polymer chemistry, drug discovery, and natural product synthesis. There are three primary types of metathesis reactions: ring-closing metathesis (RCM) and cross metathesis, which are commonly used for small molecule organic synthesis, and ring-opening metathesis, which is mainly applied in polymerization processes. The most notable and widely used application of olefin metathesis in organic synthesis is ring-closing metathesis (RCM), an intramolecular reaction of an acyclic diene to form a ring. This methodology enables the construction of both all-carbon and heteroatom-containing rings rich in sp3-centers, a key feature in modern medicinal chemistry. Cross metathesis involves the reaction of two olefins in an intermolecular manner, resulting in a product containing substituents from each starting olefin. The reaction is notable for its excellent functional group compatibility and tolerance to residual moisture and oxygen, making it highly effective for ruthenium-catalyzed macrocyclization to form large rings (≥12 atoms). Ring-opening metathesis polymerization (ROMP) is another important application of olefin metathesis, used to design polymers with tunable properties. ROMP has become a significant technological advancement in polymer synthesis, enabling the large-scale production of polymers due to its use of low-cost, readily available starting materials.