Synthesis of Seven-Membered Nitriles by Formal Anionic Divinylcyclopropane Rearrangement

A method for the synthesis of 3-cyanocyclohepta-1,4-diene derivatives via divinylcyclopropane rearrangement was developed. The substrate was prepared via the intramolecular alkylation of a diene with a nitrile moiety. Although heating substrates with alkenyl groups in trans -relationship failed to induce the rearrangement, treatment with a suitable base facilitated the reaction under mild conditions. This reaction was applied to the total synthesis of nardoguaianone J.