Catalytic asymmetric dearomatization of (hetero)aromatic frameworks

Catalytic asymmetric dearomative cycloaddition provides a powerful route to polycyclic chiral frameworks, yet the precise control of selectivity in such cycloadditions remains a formidable challenge. Herein we report a mechanism-guided strategy that harnesses the unique reactivity of vinylidene ortho-quinone methides as highly reactive and multifunctional synthons to realize such cycloaddition with diverse (hetero)polycyclic aromatics. Density functional theory calculations revealed that the distinctive charge distribution, orbital delocalization, and narrow frontier molecular orbital gap of the synthons underpin their multisite reactivity and predictable selectivity. Leveraging these features, we accomplished cycloadditions at challenging sites with excellent regio-, chemo-, and enantioselectivity, including the C6a-C13c site of dibenzo[c,g]carbazole, the C9-C10 site of anthracene, and the C5-C6/C5-C8 sites of quinoline. This work establishes an efficient and controllable pathway for the modular synthesis of chiral polycyclic scaffolds and expands the conceptual scope of vinylidene ortho-quinone methide chemistry.