Dearomative Skeletal Editing of Benzenoids via Diradical

Abstract

Dearomative skeletal editing of benzenoids represents a promising yet challenging strategy for the rapid construction of high-value carbon frameworks from readily accessible starting materials. Büchner reaction is a unique type of expansive skeletal editing that transforms benzenoids into functionalized cycloheptatrienes. However, due to challenges in compatibility and selectivity, achieving seamless integration of this reaction with dearomative cycloaddition within a unified system remains undeveloped. Here, we demonstrated an energy-transfer-induced intermolecular dearomative skeletal editing reaction of benzenoids with a range of electronically diverse alkynes. This protocol employed N-acylimines as diradical precursors to efficiently construct various structurally diverse polycyclic frameworks in high chemo-, regio-, and diastereoselectivities that have been previously inaccessible. The challenges related to general reactivity and selectivity issues were circumvented through the smooth merging of photoinduced skeletal editing with dearomative cycloaddition. Experimental and computational studies were performed to support the diradical mechanism and interpret the origins of the observed chemo-, regio-, and diastereoselectivities.