Organic Electrode Reactions - Fundamentals and Applications of Organic Electrochemistry - page 133

(5.9)
EGB derived from hindered phenol catalyzes a
selective double aldol condensation reaction, as
shown in Eq. 5.10 [25].
(5.10)
It is well known that the substrate molecule
itself also serves as an EGB. For instance, as
shown in Eq. 5.11 , a catalytic amount of EGB
efficiently catalyzes aldol condensation. In this
reaction, aldehyde itself is cathodically reduced
to generate a trace amount of its radical anion,
which acts as a base to abstract the α-proton
from unreacted aldehyde, and aldol
condensation proceeds successively [26].
Finally, eliminating hydroxyl ion would act as
an EGB in a manner similar to a chain reaction.