Methods for Organic Electrosynthesis - Fundamentals and Applications of Organic Electrochemistry - page 109

nucleophiles (nucleophilic addition). However,
in the case of sulfide with a strongly acidic
α-hydrogen, α-deprotonation of the radical
cation occurs predominantly and eventually
α-nucleophilic substitution takes place
selectively. Among the substitution reactions,
fluorination is of great importance in synthetic
organic chemistry. However, in the case of
selenides, even selenides having an
electron-withdrawing group do not always
undergo nucleophilic substitutions, and a
nucleophilic addition reaction also occurs at the
selenium atom. In contrast, anodic substitution
of organotelluides is not known and
nucleophilic addition at the tellurium atom
predominantly occurs.
(4.106)
4.7.2.4 Halogen Species
Halogen is easily oxidized and also readily
reduced. Since the redox reaction of the halide
ion is reversible, it is widely used as a mediator
for indirect electrochemical oxidation (see
Chapters 3 and 5 ).
(4.107)