Chemists break cycloaddition ‘rule-of-five’ by simply tweaking electronic properties of molecule

Tuning the substituent attached to a dialkene helps control the type of bicyclic ring formed during radical cyclisation reactions.¹ This breaks a long-standing rule of thumb, otherwise known as the ‘rule-of-five’, which chemists use to predict the outcome of such reactions. The researchers behind the work say that accessing different bicyclic rings from a common starting material could be useful to quickly screen the impact of these ring systems in drug molecules.