Catalytic Three-Component Synthesis of Functionalized Naphtho[2,1-]oxecines via a Double Bond Cleavage-Rearrangement Cascade.

A new double annulation cascade involving a [2 + 2] cycloaddition-retroelectrocyclization (CA-RE) process was first reported, leading to the generation of unprecedented dibenzoannulated naphtho[2,1-]oxecines with good to excellent yields and high stereoselectivity through catalytic scission/recombination of C-C double bonds under the mild conditions. An Y(OTf)-catalyzed three-component reaction of α-alkynyl naphthalen-2-ols with β,γ-unsaturated α-ketoesters enabled direct ring expansion of the naphthalene ring and carbon-carbon double bond cleavage/rearrangement of α-ketoesters to give macrocyclic architectures.