Generation, characterization and some reactions of 1,1-ethylene-1H-azulenium ion

Article abstract of DOI:10.1246/cl.1997.1011

The title carbocation, generated from 1,1-ethylene-1,6-dihydroazulene and trityl tetrafluoroborate in deuterated acetonitrile at - 20°C, was characterized by means of low temperature NMR spectroscopy, and was found to undergo expansion of the cyclopropane ring at elevated temperature and to react with nucleophiles to give the addition products at the cyclopropane methylene carbon.