Tetracyanocyclopentadienide anion and its electrophilic aromatic substitution

Abstract

1,4-Diethoxycarbonyl-2,3-dicyanocyclopentadienide salts have been made from 1,4-diethoxycarbonylcyclopentane-2,3-dione by addition of hydrogen cyanide, acetylation, and treatment with base. The tetracyano-cyclopentadienide anion was formed by dehydrogenation of all-trans-tetracyanocyclopentane with phosphorus pentachloride. The tetracyano-salts can be converted into halogeno-, nitro-, and acetyl derivatives by the appropriate electrophilic reagents.