Brønsted Acid Catalyzed Remote Bisvinylogous Initiated Formal [4+2] Cycloaddition Reaction of β‐Allyl Cycloalkenones With in situ Generated <i>Ortho</i> ‐Quinone Methides

In this work, we disclose that β-allyl cycloalkenones can serve as effective bisvinylogous precursors through in situ generation of trienalcohol intermediates under Brønsted acid catalysis. This strategy enables a direct and highly diastereoselective δ,ε-regioselective remote bisvinylogous initiated formal [4+2] cycloaddition of β-allyl cycloalkenones with ortho-quinone methides (o-QMs). In this process, β-allyl cycloalkenones act as dienophiles while o-QMs function as diene precursors, providing efficient access to naphthopyran derivatives with excellent selectivity. Additionally, the asymmetric variant was also investigated using a BINOL-derived chiral Brønsted acid, thereby extending the utility of this method toward enantioselective synthesis.