Intramolecular palladium-catalysed enolate arylation of 2-and 3-iodoindole derivatives for the synthesis of beta-carbolines, gamma-carbolines, and pyrrolo[3,4-b]indoles

The palladium-catalysed intramolecular alpha-arylation of carbonyl compounds with amino-tethered 2- and 3-iodoindoles provides a useful methodology for the synthesis of indolo-b-fused nitrogen heterocycles. A variety of substituted tetrahydro beta- and gamma-carbolines, and pyrrolo[3,4-b]indoles, have been prepared by means of this palladium-catalysed annulation process.