On the Effect of Diene Geometry in Intramolecular Allyl Cation Cycloadditions

Abstract

Attempted intramolecular allyl cation cycloaddition of trienol 2a, which contains a conjugated diene of Z-configuration, affords monocyclic trienes 3a,b, in contrast to related trienols known to produce [5,5]-bicyclic and/or [5,7]-bicyclic products. Cyclopentyl trienes 3a,b are isomeric with multifidene, an algal pheromone. Dimethyl trienol 6 fails to cyclize (under identical conditions), but eliminates to yield tetraene 7.