Methods for Organic Electrosynthesis - Fundamentals and Applications of Organic Electrochemistry - page 82

(4.15)
Based on this principle, selective C-O bond
cleavage at the benzylic and allylic positions can
be easily achieved, as shown in Eq. 4.16 .
(4.16)
Although the C-F bond is not so easily cleaved
by reduction owing to its larger bond energy
compared to that of the C-H bond, fluorine
attached to a benzylic position or α to carbonyl
and imino groups is readily removed by
cathodic reduction. This is also quite similar to
the cases shown in Eqs. 4.15 and 4.16 . As shown
in Eq. 4.17 , electron transfer first takes place at
the aromatic ring or carbonyl and imino groups
followed by β-elimination of the fluoride ion
[25]. When the cathodic reaction shown in Eq.
4.17 is carried out in the absence of Me 3 SiCl,
further cathodic reduction takes place to result
in successive elimination of fluorine atoms,
providing complicated products.