Organic Electrosynthesis - Fundamentals and Applications of Organic Electrochemistry - page 268

of dienes in NaClO 4 /MeNO 2 generated
quinones, which underwent Diels-Alder
reaction with the dienes to provide cyclic
products in excellent yields [98]. Use of an
uncoated glassy carbon anode also generates
quinones from hydroquinones, but the
coexisting dienes are easily oxidized and
decompose prior to reaction with the quinones.
However, when a PTFE-fibre-coated glassy
carbon electrode is used, the easily oxidizable
diene is maintained on the PTFE-fibres and
only the polar hydroquinones can reach the
electrode through the hydrophobic fibres, as
shown in Figure 6.33 . Next, the anodically
generated hydrophobic quinones immediately
react with the dienes adsorbed on the PTFE
fibres, and the resulting hydrophobic products
are also maintained on the fibres to avoid
further oxidation of the products. This novel
method is useful for the synthesis of various
terpenes [99].