Herein we report a palladium-catalyzed [2+2+1] annulation among 3-iodochromones, bridged olefins, and cyclopropenone, giving a variety of chromone fused cyclopentanones that are of interest in medicinal chemistry. This protocol involves...

A series of chromone fused methylenecyclopentanes are efficiently constructed in moderate to good yields by Pd-catalyzed [2 + 2 + 1] annulation, in which aziridine is used as a vinylidene unit by cleavage of two C–N bonds for the first time.

A variety of chromone-containing polycyclic compounds are efficiently generated via Pd-catalyzed decarboxylation [2 + 2 + 2] annulation of 3-iodochromones, bridged olefins and o-bromobenzoic acids, in which o-bromobenzoic acids were employed as the electrophilic aryl units.