Intermolecular sequential [4 + 2]-cycloaddition–aromatization reaction of aryl-substituted allenes with DMAD affording phenanthrene and naphthalene derivatives

Abstract

An efficient entry to phenanthrene and naphthalene derivatives through intermolecular sequential [4 + 2]-cycloaddition–aromatization reactions of aryl-substituted allenes with DMAD in the absence of any catalyst was discovered. In this reaction the aromatic ring and the adjacent carbon–carbon double bond of the allene unit acted as the 1,3-diene.