A base-modulated chemoselective synthesis of 3-cyanoindoles or 4-cyanoquinolines using a palladium-catalyzed N-heterocyclization

A selective methodology for the synthesis of either 3-cyanoindoles or 4-cyanoquinolines via a base-modulated palladium-catalyzed reductive N-heterocyclization from a common 1-cyano-1-(2-nitrophenyl)-1-alkene precursor is described. The required starting materials were prepared either by a Kosugi–Migita–Stille coupling of 2-halo-1-nitrobenzenes with a tributyl(1-alkenyl)stannane or by a vicarious nucleophilic substitution (VNS) of nitrobenzenes followed by a Knoevenagel condensation with an aldehyde.