Toward an understanding of the cubyl and related caged carbocations

The product ratios observed upon fluorodeiodination of a series of caged cyclobutane-containing iodides are explained on the basis of the relative energies of the intermediate cations involved. The relative energies of these cations have been evaluated by ab initio calculations with the inclusion of electron correlation (MP2/6-31G * //RHF/3-21G; MP2/6-31G ** ), the results of which lend support to the view that hyperconjugative involvement of the cationic center with the α,β and β,γ C-C bonds in each cyclobutyl moiety is the critical factor responsible for the stabilityof the cation in each case