Synthesis of 2-cyano-1,4-cycloheptadiene derivatives via divinylcyclopropane rearrangement and alkylation of novel cycloheptadienyl anion species

An efficient synthetic method for 2-cyano-1,4-cycloheptadiene derivatives was developed on the basis of divinylcyclopropane rearrangement. The substrates were prepared from 2-vinylcyclopropanecarbonitrile and an α,β-epoxysilane through a Peterson olefination. The resulting 2-cyano-1,4-cycloheptadiene underwent deprotonation at the doubly allylic methylene group to afford a novel cycloheptadienyl anion, a useful intermediate for synthesizing polycyclic compounds.