Selective Syntheses of Benzo[<i>b</i>]carbazoles and C3‐Substituted Indoles <i>via</i> Tunable Catalytic Annulations of <i>β</i>‐Alkynyl Ketones with Indoles

Abstract

Abstract Tunable catalytic annulation reactions of β alkynyl ketones with indoles have been developed, enabling multiple chemical bond‐forming events to selectively access skeletally diverse indole‐containing heterocycles with generally good yields. Silver‐catalyzed intermolecular benzannulation reaction of β ‐alkynyl ketones with indoles afforded tetracyclic benzo[ b ]carbazoles whereas isochromen‐1‐yl‐substituted indoles could be obtained using the same silver catalysis by lowering the reaction temperature (0 °C or rt). Interestingly, using Sc(OTf) 3 and AgOTf as a combined catalytic system led to the formation of C3‐naphthylated indoles via intramolecular benzannulation reaction. magnified image