Rapid and Atom-Economical De Novo Access to Polysubstituted Quinolines via Sequential C-C Bond Cleavage and Reassembly.

Herein, we report a Cu(II), Rh(III) relay-catalyzed multicomponent reaction of easily available arylformylacetonitriles and alkynes, enabling the efficient de novo synthesis of polysubstituted quinolines via two steps in a "one-pot" manner. Various polysubstituted quinolines could be provided in up to 88% yields for 23 examples. The title products exhibit favorable fluorescence emission. Mechanistic studies suggest that unique domino two-C-C bond cleavage and the formation of multiple new bonds (five C-C bonds and one C-N bond) are involved in this process. This protocol features mild reaction conditions and is extremely simple and scalable. The luminescence of the products enhances their promising applications in functional materials.