Pleiadiene,27, can be efficiently prepared in 45% yield by copper catalyzed intramolecular coupling of the bis-Grignard reagent of 1,8-trans-(β-bromovinyl)naphthalene,5. Also obtained in 6% yield is the unsaturated 14-membered ring compound28. Whereas the bis(β-bromovinyl) compound5is readily available from 1,8-divinylnaphthalene, α-bromovinyl compounds are obtained from divinylbenzenes. On coupling the Grignard reagent from 1,4-bis(β-bromovinyl)-benzene, only linear dimeric products were obtained.