Linear Acene Derivatives. New Routes to Pentacene and Naphthacene and the First Synthesis of a Triptycene with Two Anthracene Moieties

Article abstract of DOI:10.1021/jo00231a001

The cycloaddition of o-xylylene to arene 1,4-endoxides was used to construct linear arene derivatives.For example, heating benzocyclobutene 4 with anthracene 1,4-endoxide (10) followed by dehydration and dehydrogenation gave pentacene in three steps and 64percent overall yield.An analogous sequence but with naphthalene 1,4-endoxides gave naphthacenes.Dehydration of the di adducts from 4 and anthracene 1,4:5,8-diendoxides (5) gave a mixture of 5,9,14,18- and 5,8,15,18-tetrahydroheptacenes 3 and 9.The previously unknown triptycene 2 was synthesized from 5,14-dihydropentacene (12), an intermediate in the new pentacene synthesis, in three steps and 29percent overall yield.