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

Abstract

AbstractTunable 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