Merging metathesis and photochemical Csp3-H activation: Access to masked β-formyl hexanolides and their rearrangement to furofuranones

β-Masked formyl hexanolides were prepared by a three-step sequence including esterification of homoallylic alcohols, ring-closing metathesis and the photochemically induced addition of dioxanyl radical. When treated under oxidative conditions, the adducts underwent cleavage of the ketal group leading after rearrangement to parent furofuranones, structures found in some biological active compounds. [Display omitted]