Graphical Abstract
Methyl substituents—and the temperature—influence the NiII-catalyzed isomerization of 1,5-cyclooctadienes. For example, reaction of isoprene in refluxing hexane leads, via 1, to the bicyclic compound 2 and reaction of isoprene and trans-piperylene leads, via 3, to the highly strained tricyclic cyclopropane derivative 4. The structures of the carbon frameworks were established by 2D INADEQUATE NMR experiments.
