Zirconium-mediated selective synthesis of 1,2,4,5-tetrasubstituted benzenes from two silyl-substituted alkynes and one internal alkyne.

Selective synthesis of 1,2,4,5-tetrasubstituted benzenes was achieved via formation of 2,5-bis(trimethylsilyl)zirconacyclopentadienes from 2 equiv of TMS-substituted alkynes with Cp(2)ZrBu(2) and Cu-mediated formation of 1,4-disilylbenzene by cycloaddition of zirconacyclopentadienes to disubstituted alkynes. Preparation of 1,2,3,4,9,10-hexasubstituted pentacene and 2,3,6,11-tetrasubstituted naphthacene derivatives were demonstrated by a homologation or coupling method using tetrasubstituted benzene.