Copper(II)-Catalyzed Carbon–Carbon Triple Bond Cleavage of Internal Alkynes for the Synthesis of Annulated Indolizines

Abstract

Cleavage of C≡C bond in butynedioates via copper(II)-catalyzed reaction has been achieved, leading to the synthesis of benzo[f]pyrido[1,2-a]indole-6,11-diones in high yields by one-pot three-component reactions. In this unprecedented C≡C bond cleavage reaction of internal alkynes, both fragments from the alkyne are successively incorporated into the products.