Organic Electrode Reactions - Fundamentals and Applications of Organic Electrochemistry - page 128

Figure 5.5 Homo coupling of aryl halide using
Pd(0) complex

5.1.2.7 Electrosynthesis Using Mediator
Immobilzed on Solid

N -Oxyl radicals exemplified by

2,2,3,3-tetramethylpiperidinyl- N -oxyl
(TEMPO) are useful mediators for efficient
oxidation of alcohols and amines. The
mediators have never been recovered and
reused after electrolysis, but recyclable
mediators have recently been developed from
an atom economical aspect. Mediators are
immobilized on the surface of silica gel through
silane coupler, and are readily recovered and
recycled after electrolysis. Thus, the
combination of halide ions and
TEMPO-immobilized silica gel or polymer
particles as a disperse phase enables a mediated
electrocatalytic reaction in aqueous
NaBr-NaHCO 3 as a disperse media [17].
Asymmetric oxidation of alcohols is also
possible using a chiral N -oxyl mediator [18].

5.2 Electrogenerated Acids and
Bases

5.2.1 Electrogenerated Bases

Acids and bases play very important roles in
organic synthesis. It is well known that when
aqueous solution containing a neutral