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The cyclodimerization of aryl vinyl sulphones: A facile and specific reaction when activated by cathodic electron transfer
Te
Lettax.VoL31,No.5.Pp 667-66&1!JW
oo4o4o39/90 $3.00 + ml
pfh&dillOlcltBriuin
W-b&
THE CYCLODIMERIZATION REACTION
OF ARYL VINYL SULPIIONES
WHEN ACTIVATED
BY CATHODIC
: A FACILE
ELECTRON
AND SPECIFIC
TRANSFER
by Jacques DELAUNAY, Gilles MABON, Armelle ORLIAC and Jacques SIMONET*
au CNRS, UniversitB de Rennes 1, Beaulieu, 35042 RENNES(FRANCE). Laboratoire
d’Electrochimie,
Associo
Summary ; Aryl vinyl sulphones, when “reduced” under well defined experimental conditions, do not lead to cleavage products or to hydrodimers but to cyclodimets, namely tram bii - 1,2-(aryl sulphonyl)-cyclobutanes. Tbe reduction of activated oletins remains one of the highly successfitl fields of organic electrochemistry. The
out come of the reaction is to produce a hydrodimer, the electron-withdrawing group A being or not modified by subsequent pmcesses : 2
sA
A//-A
The industrkl synthesii of adiponitrile from acrylonitrile is well known1 . Rather surprismgly, similar mactions were not described with unsaturated sulphones. This activating group is considered to be of high interest 2 since it can be elimiited
later by simple reducing cleavage. Up to now, however, the conditions to form selectively such
dimets were unclear and unsuccessfitl 3. The present preliminaty paper describes the first cathodic cyclodimerization of olefm activated by different aryl sulphonyl groups. The formation of a cyclobutane requires only very small amounts of electricity and is therefore “el ecmxamlyzed”. In other words, the reaction is activated by single electron tmnsfer : Ar-so2
2
Ar-S02-
withAr=Phenyl:
)
CH = CH2
la,-4-Tolyllb,-4-Methoxyphenyl
2
lc,=2-Naphthylld.
Results and experimental conditions are collected in table 1. All sulphones studied exhibit, at high sweep rates (v>ZOV.s-l), a main voltammetric step which appears to be speclflc of 1 and not of 2 within the potential range [-1.3OV to - l.S!iV]vs Ag/Ag I/I- O.lM. The potentials applied can be varied from that of the threshold to that of the peak. Thus, entries 1 and 2, corresponding to an activation by low cathodic currents (electrolyses ended after 0.1 and 0.2 F. molal), afford rather good yields of 2. On the contrary, more cathodic potentials lead to a decay of the yield of cyclobutane, probably because its cathodic reduction camrot be avoided. On the contrary, an indirect activationappearstobe
successful (entry lo), when a mediator Ph-CH=C(CN)OPh
z is added to the electrolysis solution. Several other side-products are isolated in very low yields. Most of them are hydmdimem and their products of anionic elimination.
667
668
Since (2+2) q&additions
from a, 6 - un&wted
tutlphones are rather tare (photochemical activation4), and
the only reported cyclodimerlzatlon is under those conditions that of bemxthiophene dioxide 5, the electrochemical method appears to be of very high interest. This intereat is probably reinforced by the tact that common reductants (NaorKinTHF)andstrongbasea(LiBuinhexane)arenotcapableofinducingcatalyticchainsleadingto~.
9
10
ld &+l
- 1.30
0.1
57
- 1.20
0.2
74
unreacted g:4%
zzg? 76% Tablt
Retwlts of cathodic cyclodimerlzation of 1 as a function of the applied potential to the mercury pool.
Reactions arc condllctcdin aalydms dimethylformamide containing O.lM tetmethylammonium perchlorate with 3 milliioles
of 1 (Entry 10 : mtio [la1 / 131-6). A divided cell was used.
l-
MM. Balzer, “Electrolytic reductive coupling”, ln “Organic electrochemistry”, MM. Baler and H. Lund Ed., M. Dekker Inc., New York (1983) (and referencea cited therein). .
2-
J. Simonet “Electrochemistry
3-
(a) N. Djeghidjegh. These de Doctorat, Univetsiti de Rennea I 1988. (b) N. Djeghidjegh and J. Simonet, J.
4-
Chem. Sot. Chem. Commun. 1317, (1988). M.S. ElFaghiElAmoudi,P.GenesteandJ.L.Olive,J.Org.
5-
MS. El Faghi El Amoudi, P. Geneate and J.L. Olive, Nouv. J. Chim., A 25 1, ( 198 1).
of sulphones and sulphoxides”
sulphoxides”, S. Patai, 2. Rappopott and C.Stirlii
(Received in France 15 November 1989)
in the “Chemistry
of sulphones and
Ed., J. Wiley, New York (1983).
Chem.,&,4258,
(1981).
Lettax.VoL31,No.5.Pp 667-66&1!JW
oo4o4o39/90 $3.00 + ml
pfh&dillOlcltBriuin
W-b&
THE CYCLODIMERIZATION REACTION
OF ARYL VINYL SULPIIONES
WHEN ACTIVATED
BY CATHODIC
: A FACILE
ELECTRON
AND SPECIFIC
TRANSFER
by Jacques DELAUNAY, Gilles MABON, Armelle ORLIAC and Jacques SIMONET*
au CNRS, UniversitB de Rennes 1, Beaulieu, 35042 RENNES(FRANCE). Laboratoire
d’Electrochimie,
Associo
Summary ; Aryl vinyl sulphones, when “reduced” under well defined experimental conditions, do not lead to cleavage products or to hydrodimers but to cyclodimets, namely tram bii - 1,2-(aryl sulphonyl)-cyclobutanes. Tbe reduction of activated oletins remains one of the highly successfitl fields of organic electrochemistry. The
out come of the reaction is to produce a hydrodimer, the electron-withdrawing group A being or not modified by subsequent pmcesses : 2
sA
A//-A
The industrkl synthesii of adiponitrile from acrylonitrile is well known1 . Rather surprismgly, similar mactions were not described with unsaturated sulphones. This activating group is considered to be of high interest 2 since it can be elimiited
later by simple reducing cleavage. Up to now, however, the conditions to form selectively such
dimets were unclear and unsuccessfitl 3. The present preliminaty paper describes the first cathodic cyclodimerization of olefm activated by different aryl sulphonyl groups. The formation of a cyclobutane requires only very small amounts of electricity and is therefore “el ecmxamlyzed”. In other words, the reaction is activated by single electron tmnsfer : Ar-so2
2
Ar-S02-
withAr=Phenyl:
)
CH = CH2
la,-4-Tolyllb,-4-Methoxyphenyl
2
lc,=2-Naphthylld.
Results and experimental conditions are collected in table 1. All sulphones studied exhibit, at high sweep rates (v>ZOV.s-l), a main voltammetric step which appears to be speclflc of 1 and not of 2 within the potential range [-1.3OV to - l.S!iV]vs Ag/Ag I/I- O.lM. The potentials applied can be varied from that of the threshold to that of the peak. Thus, entries 1 and 2, corresponding to an activation by low cathodic currents (electrolyses ended after 0.1 and 0.2 F. molal), afford rather good yields of 2. On the contrary, more cathodic potentials lead to a decay of the yield of cyclobutane, probably because its cathodic reduction camrot be avoided. On the contrary, an indirect activationappearstobe
successful (entry lo), when a mediator Ph-CH=C(CN)OPh
z is added to the electrolysis solution. Several other side-products are isolated in very low yields. Most of them are hydmdimem and their products of anionic elimination.
667
668
Since (2+2) q&additions
from a, 6 - un&wted
tutlphones are rather tare (photochemical activation4), and
the only reported cyclodimerlzatlon is under those conditions that of bemxthiophene dioxide 5, the electrochemical method appears to be of very high interest. This intereat is probably reinforced by the tact that common reductants (NaorKinTHF)andstrongbasea(LiBuinhexane)arenotcapableofinducingcatalyticchainsleadingto~.
9
10
ld &+l
- 1.30
0.1
57
- 1.20
0.2
74
unreacted g:4%
zzg? 76% Tablt
Retwlts of cathodic cyclodimerlzation of 1 as a function of the applied potential to the mercury pool.
Reactions arc condllctcdin aalydms dimethylformamide containing O.lM tetmethylammonium perchlorate with 3 milliioles
of 1 (Entry 10 : mtio [la1 / 131-6). A divided cell was used.
l-
MM. Balzer, “Electrolytic reductive coupling”, ln “Organic electrochemistry”, MM. Baler and H. Lund Ed., M. Dekker Inc., New York (1983) (and referencea cited therein). .
2-
J. Simonet “Electrochemistry
3-
(a) N. Djeghidjegh. These de Doctorat, Univetsiti de Rennea I 1988. (b) N. Djeghidjegh and J. Simonet, J.
4-
Chem. Sot. Chem. Commun. 1317, (1988). M.S. ElFaghiElAmoudi,P.GenesteandJ.L.Olive,J.Org.
5-
MS. El Faghi El Amoudi, P. Geneate and J.L. Olive, Nouv. J. Chim., A 25 1, ( 198 1).
of sulphones and sulphoxides”
sulphoxides”, S. Patai, 2. Rappopott and C.Stirlii
(Received in France 15 November 1989)
in the “Chemistry
of sulphones and
Ed., J. Wiley, New York (1983).
Chem.,&,4258,
(1981).