π-Extended Alkylidenecycloproparenes

Abstract

Reaction of benzene-1,4-dicarboxaldehyde with anion 6 derived from 1,1-bis(trimethylsilyl)cyclopropa[b]naphthalene 1 gives 4-(methylidene-1H-cyclopropanaphthalenyl)benzaldehyde 7 as a minor product and 1,4-bis(methylidene-1H-cyclopropanaphthalenyl)benzene 8 as the major product of the reaction. With 4-{(E)-2-[4-(dimethylamino)phenyl]ethenyl}benzaldehyde 14, this same anion affords the stilbene-substituted π-extended (1-arylmethylidene)cyclopropanaphthalene 15 as a sparingly soluble orange-red powder.