Rhodium-Catalyzed/Copper-Mediated Tandem C(sp2)–H Alkynylation and Annulation: Synthesis of 11-Acylated Imidazo[1,2-a:3,4-a′]dipyridin-5-ium-4-olates from 2H-[1,2′-Bipyridin]-2-ones and Propargyl Alcohols

DOI: 10.1021/acs.orglett.6b00177