Palladium-catalyzed decarboxylation [2 + 2 + 2] annulation approach to chromone-containing polycyclic compounds†

Abstract

We present herein a palladium-catalyzed decarboxylation [2 + 2 + 2] annulation with 3-iodochromones, bridged olefins, and o-bromobenzoic acids to give various exo-chromone-containing polycyclic compounds (49 examples, up to 92% yield), in which o-bromobenzoic acids were employed as the electrophilic aryl units. Gram-scale experiments, late-stage modification of estrone, and further transformations of products show a great potential of this palladium-catalyzed Heck coupling/C(sp²)–H activation/decarboxylation cascade for drug discovery and development.