Rearrangements of pinane derivatives. Part IV. Solvolysis of the myrthanyl toluene-p-sulphonates

Abstract

Methanolyses of the cis- and trans-myrtanyl toluene-p-sulphonates both proceed by part unimolecular and part bimolecular mechanisms. The unimolecular reactions proceed with synchronous shift of the C-2 hydrogen to give the pinan-2-yl cation. Formation of this ion by an indirect route removes the counterion from the vicinity of the carbonium ion centre, thus diminishing ion-pair effects on the reactions of the ion. Both isotope effects and product studies indicate that the bimolecular reaction proceeds by direct attack of the nucleophile on the substrate, rather than by attack on an ion-pair.