REARRANGEMENT STUDIES WITH C14: III. THE FRIEDEL–CRAFTS ALKYLATION OF ANISOLE WITH 2-PHENYLETHYL-1-C14 CHLORIDE AND 2-PHENYLETHANOL-1-C14

The Friedel–Crafts alkylation of anisole with 2-phenylethyl-1-C 14 chloride and 2-phenylethanol-1-C 14 resulted in a product, p-methoxydibenzyl, which showed isotope position rearrangement corresponding to an essentially 50% rearrangement of the C 14 labeled atoms from the C-1 to the C-2 positions in the original chloride and alcohol. If one were to assume that both rearrangement and alkylation involve the same intermediate, these results may be explained on the basis of either an ionic mechanism for the Friedel–Crafts alkylation, the rearrangement being attributed to the formation of the phenylethyl cation, or a displacement mechanism in which the alkylation product is formed from a reaction between anisole and a rearranged polarized complex of aluminum chloride and alkylating agent. The possibility that rearrangement in the Friedel-Crafts alkylation may arise from a process separate from and prior to the alkylation stage itself is also discussed. On this basis, the intermediates involved in the rearrangement and alkylation stages will not necessarily have to be the same.