Copper catalysis in the construction of indole and benzo[b]furan rings.

This perspective reports on some of the main copper-catalyzed routes to the construction of the pyrrole and furan rings incorporated into the indole and benzo[b]furan systems, respectively. The first part illustrates the synthesis of indoles through cyclizations of 2-alkynylanilid(n)es, preformed or generated in situ, and cyclizations via intramolecular N-arylation, N-vinylation, and C-C bond forming reactions. The second part illustrates the synthesis of benzo[b]furans through cyclizations of preformed 2-alkynylphenols, domino synthesis of 2-alkynylphenols/cyclization processes, and cyclizations via intramolecular O-arylation reactions.