Cyclisations of organolithiums onto aromatic rings

The synthesis of bicyclic and other polycyclic structures by intramolecular nucleophilic attack of organolithiums on aromatic rings is reviewed. This review begins with some early observations of cyclisation-rearomatisation reactions that suggested the possibility of using aromatic rings to trap organolithiums. More recent results have shown that anion-stabilising groups, particularly sulfur- or amide-containing functional groups, are able to retard the rearomatisation step and may lead to dearomatised products. Recent optimisation of such reactions, particularly those employing aromatic amides, has allowed them to be used as key steps in a number of syntheses of natural products and their analogues.