Transition State Regioselectivity

Transition state regioselectivity refers to the preference of a chemical reaction to form one specific arrangement of atoms (regioisomer) over others during the most critical moment—called the transition state—when bonds are breaking and forming. This preference depends on factors like the stability of intermediates and the distribution of electron density, which influence how the reaction proceeds. Essentially, the reaction "chooses" the pathway that requires the least energy and leads to the most stable arrangement, guiding the formation of a specific product among possible options.