Intramolecular Wittig reaction of α,α′-dioxocycloalkylidenetributylphosphoranes: formation and trapping of cycloalkyn-2-ones with five- and six-membered rings
Abstract
Reaction of the title phosphoranes with homophthalic anhydride or 1,3-diphenylisobenzofuran in the presence of Me3SiCl gave the corresponding Diels–Alder adducts, indicating the transient intermediacy of cycloalkyn-2-ones with five- and six-membered rings.