Varying amounts of polymer Evidence for the structures and nance spectroscopy. undecatrien-4-ol (I11 and IV) j have been prepared and their dehydration reactions investigated. acid-catalyzed dehydrations were mainly associated with allylic rearrangements. and mixtures of four acyclic isomers (CISHZO) were formed in most cases. niechanisrn of formation of the dehydration products is presented.