Formal one-carbon insertion into esters via copper-catalyzed diyne cyclization/[1,2]-acyl shift†

Transition metal-catalyzed formal one-carbon insertion into carbonyl compounds is an efficient method for the preparation of complex molecules. Herein, we report a copper-catalyzed intramolecular formal one-carbon insertion into esters through a cascade diyne cyclization/[1,2]-acyl shift pathway, enabling the atom-economical synthesis of various chromeno[3,4-c]pyrroles bearing quaternary carbon stereocenters under mild reaction conditions. Moreover, moderate enantioselectivities are achieved in the catalytic asymmetric formal one-carbon insertion. The reaction mechanism is illustrated through computational studies.