The Sn Mechanism in aromatic compounds. XXIII. Substituent groups attached by saturated sulphur

Abstract

The activating power of p-SMe and p-SMe₂⁺ in aromatic nucleophilic substitution has been compared with available data for ?NH₂, -NMe₃⁺, and OMe. The ?Sme₂⁺; group is very powerfully activating and there is strong evidence for a -T effect of ?Sme₂⁺ but not of -SMe, involving expansion of the valency shell beyond an octet. The -SMe group, like -Cl, -Br, and -I, is however also activating, whereas ?NH₂, -OMe, and -F are more or less deactivating.