Novel synthesis of bridged phenylthienylethenes and dithienylethenes via Pd-catalyzed double-cyclization reactions of diarylhexadienynes.

[reaction: see text] Bridged phenylthienylethenes and dithienylethenes were synthesized via Pd-catalyzed double-cyclization reactions of (Z,Z)-1,6-diaryl-1,5-hexadien-3-ynes. Pd-catalyzed as well as photoinduced Z/E isomerization of the products were also investigated.