Full text of DOI:10.1016/S0040-4039(01)87191-4

Tetrahedron Letters No. 12,
1059
1062.
Press Ltd. 1979. Printed in Great Britain.
ELECTROCHEMICAL REDUCTION OF COMPLEX SULFONAMIDES
A CATHODIC SYNTHESIS OF AZA AND
LIGANDS
Jacques
and Georges
Groupe
BP 45, F
(b) Laboratoire de Chimie Organique Biologique,
63170
Organique, Universitd de Clermont II,
63170
de Clermont II,
BP 45, F
Recent reports on interesting properties of multiheteromacrocycles
and specially their tendency to complex with metals have prompted us to exami-
ne a synthetic route to poly-aza and poly-oxa-aza-cycloalkanes, which was ge-
l-5
The last step in
nerally carried out via macrocyclic polysulfonamides
this synthesis is the removal of the tosyl groups, Such a removal can be
achieved electrochemically and we wish here to report the successful cathodic
cleavage of N-S bonds in the poly -p-toluenesulfonamides according to the ge-
neral scheme
Ts-N
IV’,
2
The electrochemical reduction of these substrates can be carried out
the direct reduction in solvent-electrolyte couples
by using two methods
such as DMF
and/or the indirect reduction by
7-11
or
This second method al-
some well chosen electrogenerated anion radicals
lows the use of alkali metal salts as supporting electrolytes, in dipolar
aprotic solvents, when the primary electron source is the mercury cathode.
In the case of macrocyclic polysulfonamides, such as I-V, table 1
shows that the electrochemical deprotection is feasible often in good yield,
when indirect reduction using the pyrene anion radical as reducing reagent is
performed. Similar results were found with direct
a more problematic work up.
although with

12
1062
b
a
vs
vs
: Cyclic voltammograms at a stationnary mercury electrode of pyrene
M) in the presence of (I) ((I))s/(pyrene)s, before and after
(a) x = 0 (b) x = 10
after consumption of 8.2 F.
lometry at
Moi!Supporting-electrolyte
in aprotic DMF. Sweep rate 10
In the three cases the starting potential is
Cyclic voltammograms at a stationnary mercury electrode of (I) in
the presence of phenol m = (phenol)s/((I))s. Concentration of (I)
(a) m (b) m = 5 m = 7 (d) Medium
100 mV.s
Figure 2
m
Sweep rate
References
:
1
2
3
H. Stetter and E.E. ROOS, Chem. Ber.,
H. Stetter and K.H. Mayer, Ber.,
and T.J. Atkins, J. Amer. 'Chem.
W. Wehner and F. Liebigs Ann. Chem., 916, (1976).
566, (1954).
1410, ( 1961) .
2268, (1974).
J.E.
W.
4
5
6
7
M. Hediger and T.A. Kaden, J.C.S. Chem. Comm., 14, (1978).
P.T. Cottrell and C.K. Mann, J. Amer. Chem. 3579, ( 1971) .
G. Jeminet and J. Simonet, Electrochim. 1395, (1977)
H. Lund and J. Simonet, J. Electroanal. Chem., 205, (1975).
J. Sease and R. Reed, Tetrahedron Lett., 393, (1975).
Bendersky and V.G. Mairanovskii, J. Electroanal. Chem.,
R.
8
9
401,
10
(1977).
J. Simonet and
H. Lund,
Chem.
909, (1977).
11
(Receive& in UK 15
January