Stereochemical studies. Part XLVII. Conformational analysis of many-membered ring compounds. The cyclododecenes

Abstract

The equilibrium has been determined for an eight-component system of position- and cis–trans-isomeric 1,1,4,4-tetramethylcyclododecenes; enthalpies of hydrogenation have been measured for the cis- and trans-1,1,4,4-tetramethylcyclododec-8-ene pair; large differences in the relative stabilities and hydrogenation enthalpies have been found. The results are discussed in conformational terms and possible conformations of the cis- and trans-cyclododecenes are considered.