Regioselective [5 + 1] rearrangement–annulation: a new and efficient domino route to highly functionalized [1,6]naphthyridines

Abstract

A new [5 + 1] rearrangement–annulation for the regioselective formation of polyfunctionalized [1,6]naphthyridines is described. The new construction of a pyridin-2(1H)-one skeleton and its alkylation on the pyridin-2(1H)-one unit were readily achieved through a novel sequential [4 + 2] cyclization–ring opening–intramolecular cyclization–re-cyclization–elimination of urea process.