Construction of Functionalized ortho‐Naphthoquinone Methides via Site‐Selective Ring Opening of 1‐Siloxy‐1,4‐epoxy‐1,4‐dihydronaphthalenes

Abstract 1‐Siloxy‐4‐(benzyloxy)methyl‐1,4‐epoxy‐1,4‐dihydronaphthalenes, generated from benzynes and furans, underwent automatic site‐selective ring opening because of the synergetic effect of the steric strain of the 1,4‐epoxy moiety and the electron‐donating ability of the siloxy group on the acetal structure to afford the precursors of ortho ‐naphthoquinone methides ( o ‐NQMs). Subsequent Lewis acid‐facilitated o ‐NQM formation and annulation with olefins afforded multi‐fused heterocycles. Notably, the consecutive hexacyclic skeleton of rubioncolin B was constructed via solvent‐dependent regioselective annulation of naphthofuran derivatives.