An aerobic [2 + 2 + 2] Cyclization via Chloropalladation: From 1,6-Diynes and Acrylates to Substituted Aromatic Carbocycles

A Pd-catalyzed aerobic [2 + 2 + 2] cyclization of 1,6-diynes and acrylates proceeding through a chloropalladation process has been developed. Polysubstituted five-membered aromatic carbocycles/heterocycles were obtained in good to excellent yields. The results of the mechanistic study are consistent with the proposed reaction mechanism.