Application of the Intramolecular Aza-Wittig Reaction to the Synthesis of Vinylogous Urethanes and Amides

Article abstract of DOI:10.1021/jo00225a066

The treatment of ω-azido β-dicarbonyl derivatives with 1 equiv of triphenylphosphine leads to a transient phosphinimine (Staudinger reaction), which cyclizes into vinylogous urethanes and amides via an intramolecular aza-Wittig reaction in excellent yields.The starting azides were obtained by a nucleophilic substitution by NaN3 in Me2SO on the corresponding ω-halo β-dicarbonyl derivatives that were accessible by the γ-alkylation of β-dicarbonyl compounds with α,ω-dihaloalkanes.