Construction of Fused Oxacyclic Compounds via Dual α- and β-C–H Functionalization and Ring Decomposition of Cyclic Ethers

A new synthetic method for the synthesis of bicyclic scaffolds featuring a dihydropyran and tetrahydrofuran (THF) hybrid in the fashion of a fused structure with excellent <i>syn</i>-selectivity is realized via the reactions of enaminones and THF. In addition to displaying a dual role as both a cyclic fragment and a one-carbon synthon, the current method also shows a rarely known mode of two vicinal C-H bonds' functionalization in THF or analogous oxa-heterocycles.