TiCl4/Et3N-Promoted Three-Component Condensation between Aromatic Heterocycles, Aldehydes, and Active Methylene Compounds

A one-pot methodology for the synthesis of polyfunctionalized indole derivatives by a TiCl4/Et3N-promoted trimolecular condensation of aldehydes, indole heterocycles, and various activated carbonyl compounds is reported. Rationalization of these reactions and extension to other heterocyclic systems is also described.