Cross-Conjugated Oligo(enynes)

Synthetic efforts toward cross-conjugated enyne oligomers are detailed in this account. This includes the realization of iso-polydiacetylenes (iso-PDAs) and iso-polytriacetylenes (iso-PTAs), the cross-conjugated constitutional isomers of polydiacetyl­enes and polytriacetylenes, respectively. These compounds can be readily accessed via palladium-catalyzed cross-coupling reactions between vinyl triflates and terminal alkynes, or oxidative acetylenic coupling of terminal alkynes using Hay methodology. Electronic communication along the π-framework of these oligomers is described as a function of both oligomer length and terminal substitution.