Olefin metathesis is a chemical reaction that involves the exchange of alkene groups between different molecules. This process allows for the formation of new alkenes by breaking and reforming carbon-carbon double bonds. It is widely used in organic synthesis and materials science to create complex molecules and polymers. The reaction is typically facilitated by catalysts, such as Grubbs catalysts, which help to lower the energy barrier for the reaction. Olefin metathesis has applications in various fields, including pharmaceuticals, plastics, and renewable energy, making it an important tool in modern chemistry.