KINETICS, SELECTIVITY, AND MECHANISM OF THE REACTIONS OF ARENES WITH ADAMANTYL CARBOCATIONS IN SULFURIC ACID

Data on the kinetics, selectivity, kinetic isotope effect, and the effect of the acidity of the medium on the rate of the reactions of benzene and alkylbenzenes in sulfuric acid (59-78 wt.% H2SO4) solutions of 1-adamantanol at 30 °C indicate that the direct reagents are the adamantyl carbocations (Ad+) that alkylate the arenes. The ortho positions of the benzene ring are not accessible on account of steric hindrances. The rate of attack by the Ad^+ cation on the accessible para and meta positions of the ring is controlled by the formation of a sigma complex.