Pd-catalyzed regio and stereocontrolled mono and bis-coupling reactions of 1-bromo-6-chlorohexa-1,3,5-triene: synthesis of a naturally occurring tetraenynone

The synthesis of new 1,6-dihalogenohexatrienes is described. The chemoselectivity of pallado-catalyzed cross-coupling reaction is studied and a short synthesis, by Negishi and Sonogashira reactions, of a natural product is described.