Catalyst-controlled divergent synthesis of 2,8-dioxabicyclo[3.3.1]nonanes and benzo[c]chromen-6-ones

Abstract

Oxabicyclic scaffolds are increasingly coveted for their distinctive bioactivities. Herein, we report a BF₃·OEt₂-catalyzed Michael addition/ketalization sequence to access structurally fascinating 2,8-dioxabicyclo[3.3.1]nonanes from easily accessible 4-hydroxy-6-methyl-2H-pyran-2-one and ortho-hydroxychalcones. Simply by modulating the catalyst into CuCl, the same manifold can be steered to furnish benzo[c]chromen-6-ones, that are difficult to access by traditional methods.