Cyanoazulene-based Multistage Redox Systems Prepared from Vinylcyclopropanecarbonitrile and Cyclopentenone via Divinylcyclopropane-rearrangement Approach

Abstract

A series of 4-cyanoazulene derivatives 1–5 were synthesized from 4-cyanohexahydroazulen-1-one, which was efficiently obtained by the annulation of the seven-membered ring on the cyclopentenone skeleton via the divinylcyclopropane rearrangement. This synthetic protocol is also effective in preparing 1,1′-bi(4-cyanoazulene) (6) and its p-phenylene-extended derivative 7, which undergo multistage redox reactions exhibiting electrochemical amphotericity.