Methods for Organic Electrosynthesis - Fundamentals and Applications of Organic Electrochemistry - page 74

(b) Anode Material Dependence of Kolbe
Electrolysis
It is well known that Kolbe electrolysis with a
platinum anode generates a radical
intermediate, while that with a carbon anode
generates a cationic intermediate [1].
(c) Stereoselectivity
The reduction of 2-methylcyclohexanone at zinc
and copper cathodes in aqueous NaOH solution
provides mainly the corresponding
trans -alcohol, while that with a tin cathode
provides cis -alcohol as a major product [17].
4.4 Molecular Orbitals and
Electrons Related to Electron
Transfer
The electrons involved in electrode electron
transfer are not characteristic of electrolysis.
From the viewpoint of molecular orbitals, the
oxidation process can be explained by electron
transfer from the highest occupied molecular
orbital (HOMO) of a substrate molecule to the
anode, while the reduction process is explained
by electron transfer from the cathode to the
lowest unoccupied molecular orbital (LUMO) of
a substrate, as shown in Figure 4.8 [18].