Mayr, Herbert and Heilmann, Werner
Steric control of regiochemistry in the reactions of methyl substituted pentadienyl cations with isobutene.
In: Tetrahedron, Vol. 42, No. 24: pp. 6657-6662
The dienylic chlorides 1–5 react with isobutene in the presence of zinc chloride/ether in dichloromethane to give the acyclic adducts 6–10 in 64–91% yield. The orientation effects are in contrast to the predictions of perturbational molecular orbital theory and can be explained on the basis of steric effects.