PBr3-Mediated Cyclization of 1,7-Diyn-3,6-bis(propargyl carbonate)s: Synthesis of 5-Bromotetracenes.

A new and straightforward method for the synthesis of 5-bromotetracenes through PBr3-mediated cyclization of 1,7-diyn-3,6-bis(propargyl carbonate)s has been developed. This method offers several advantages such as easily accessible starting materials, high efficiency, and wide functional group compatibility. In addition, chloro- and iodo-substituted tetracenes were also synthesized using appropriate halogenating reagents. The utility of the 5-bromotetracene products has been illustrated by their efficient transformations through various palladium-catalyzed cross-coupling reactions.