Formal [3+2] Annulation of Silyloxyallyl Cations with 2-Naphthols: Synthesis of Tetrahydrodibenzofuran Scaffolds

Abstract

We report a new intermolecular formal [3+2] annulation strategy for the synthesis of tetrahydrodibenzofuran scaffolds under mild Brønsted acid catalysis. This modular transformation leverages silyloxyallyl cations as programmable two-atom electrophilic synthons and 2-naphthols as three-atom nucleophilic partners, enabling rapid assembly of structurally diverse tetrahydrodibenzofurans. The annulation proceeds through a one-pot cascade process involving regioselective coupling, desilylation, and intramolecular cyclization.