PHENYLATION CATIONIQUE DU CHLORO-4 ANISOLE, ETUDE DE LA MIGRATION DU CHLORE ET DU PHENYLE DANS LES CATIONS IPSO-ARENIUM.

Article abstract of DOI:10.1016/S0040-4020(01)97204-7

The phenyl cations obtained from the thermolysis of benzenediazonium tetrafluoroborate react with 4-chlroanisole to give, in addition to phenylation products at position 2 and 3, 2-chloro-4-methoxybiphenyl.The latter is formed by the attack of C6H5(1+) ipso to the chlorine followed by 1,2 migration of the halogen.This rearrangement is totally suppressed in nucleophilic solvents such as dimethylsulfoxide, whereas it is important in heterogeneous conditions.The ability of DMSO to trap the ipso-arenium ions has provided indirect evidence for the attack of C6H5(1+) ipso to the methoxy group. 1-2 migration of the phenyl group has been observed in arenium ions formed by attack of C6H5(1+) ipso to the chlorine and ipso to the methoxy group. 4-methoxybiphenyl and 2,4-dichloroanisole have not been detected by G L C so that dechlorophenylation of 4-chloroanisole must be negligible.