Cyclization reactions of N-acryloyl-2-aminobenzaldehyde derivatives: formal total synthesis of martinellic acid

Abstract

N-Alkyl acryloylamides derived from o-aminobenzaldehyde derivatives react with N-alkyl glycine derivatives to provide cis-fused pyrrole[3,2- c]quinolones in moderate yield and high diastereoselectivity. These same substrates engage in a tandem Michael–Mannich pathway on treatment with a secondary amine, providing corresponding quinolone derivatives. The elaboration of a pyrroloquinolone derivative via addition of an in situ generated functionalized copper acetylide to an in situ generated iminium ion provided the C2-substituted derivative. Global deprotection and reduction of the alkyne afford the tricyclic triamine core (as the HCl salt) found in martinellic acid.