Additive and medium effects on Lewis acid-promoted cationic pi-cyclizations of alkenyl- and alkynylcyclopentane-1,3-diones

Solvents, nucleophilic additives and Lewis and Bronsted acids influence the cationic pi-cyclizations of alkynyl- and alkenylcyclopentane-1,3-diones, which are mediated through BF3. Et2O. The nature of the reaction solvent affects regioselectivity, while the nucleophiles regulate the rates and selectivity of the cyclization reactions. These type of reactions are significant for the synthesis of bicyclic ring systems with different functional groups.