Woodward-Hoffmann rules

The Woodward-Hoffmann rules are principles in chemistry that predict whether certain reactions will occur easily or require high energy. They are based on how electrons are arranged and move during reactions, considering the symmetry and energy levels of molecules' orbitals. Essentially, these rules help chemists determine if a reaction is “allowed” or “forbidden” under specific conditions, based on changes in the molecules’ electronic structure. This understanding helps explain reaction pathways and the likelihood of certain chemical transformations happening naturally or needing special conditions.