Our retrosynthetic plan (Scheme 1) is based on the key cleavage of the N−C10 bond that reveals the octahydroquinoline system of type A. This moiety is accessible by an intermolecular Diels−Alder reaction of a 5-alkenyl-3,4-dihydropyridin-2-one B with methyl acrylate. We planned to build this N-acylaminodiene 7 by aza-annulation reaction using an acetylenic ketone of type C as a substrate. The presence of the ketone functionality was necessary to induce the ...
