2-ethynylaniline and cupric-bromide

A direct approach to 2-(aminomethyl)indoles by copper-catalyzed domino three-component coupling-cyclization of 2-ethynylanilines with a secondary amine and aldehyde has been developed. By use of a cyclic or acyclic secondary amine and aldehyde (paraformaldehyde, aliphatic or aromatic aldehydes) in the presence of 1 mol % of CuBr, 2-ethynylanilines were converted to a variety of substituted 2-(aminomethyl)indoles in good to excellent yields. Utilizing this domino reaction and C-H functionalization at the indole C-3 position, polycyclic indoles were readily synthesized. Construction of benzo[e][1,2]thiazine and indene motifs by the reaction of sulfonamide and malonate congeners is also presented.

Topics: Acetylene; Aldehydes; Aniline Compounds; Bromides; Catalysis; Copper; Cyclization; Formaldehyde; Heterocyclic Compounds; Indenes; Indoles; Malonates; Methylamines; Models, Chemical; Nitrogen; Polymers; Sulfonamides; Thiazines