A 1,3-dipole is a type of reactive species in organic chemistry characterized by a dipolar structure with positive and negative charges separated by one bond. This unique arrangement allows 1,3-dipoles to participate in various chemical reactions, particularly in cycloaddition processes, where they can react with dipolarophiles to form new cyclic compounds. Common examples of 1,3-dipoles include azomethine ylides and nitrones. These species are important in synthetic chemistry for creating complex molecules, including pharmaceuticals and natural products. Their reactivity and versatility make them valuable tools for chemists in designing new compounds.