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 dearomatizative ring expansion that transforms benzenoids into functionalized cycloheptatrienes (CHTs). However, due to challenges in compatibil-ity and selectivity, achieving seamless integration of this reaction with upgrading transformations within a unified system re-mains 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 formally rearranged heteropropellanes in high chemo-, regio- and diastereoselectivities that have been previously inaccessible. The challenges related to general reactivity and selectivity issues were circumvented through smooth merging of the photoinduced Büchner reaction with radical [6+2] cycloaddition. Experimental and computational stud-ies have been performed to support diradical mechanism and interpret the origins of the observed chemo-, regio- and dia-stereoselectivities.