Zur konformation sterisch gehinderter allyl-radikale; hyperkonjugation in verdrillten π-radikalen—VII

For the sterically hindered allyl radicals 2 and 6a, which are produced as model compounds for 1,1,3,3-tetramethylallyl radical, twist angles of about 10° are determined on the basis of their ESR coupling constants. Even the more hindered radicals 8a,b are twisted to only about 16°. These results are in contrast to the interpretation of experimental results regarding 1,1,3,3-tetramethylallyl radical and the corresponding cation.