Synthesis of Naphthoquinolizinones through Rh(III)-Catalyzed Double C(sp2)-H Bond Carbenoid Insertion and Annulation of 2-Aryl-3-cyanopyridines with α-Diazo Carbonyl Compounds.

An unprecedented Rh(III)-catalyzed double C(sp2)-H bond carbenoid insertion and annulation of 2-aryl-3-cyanopyridines with α-diazo carbonyl compounds is presented. Through this cascade reaction, a series of naphthoquinolizinone derivatives with a large π-system were efficiently prepared. The reactions could selectively afford naphthoquinolizinones with either an amine or an amide unit attached on the 11-position depending on the nature of the solvent and the additive used. Compared with literature methods, this is a more efficient, convenient, and atom-economic way to provide polycyclic heteroaromatic compounds through direct π-extension of simple aromatics via inert C-H bond activation and functionalization.