J. Am. Chem. Soc. 1997, 119, 9077-9078
9077
which left pure 1 as colorless crystals. Thus, the presumed
intermediary thiophene 1-oxide is oxidized faster than thiophene
with DMD and the yield of 1 is quantitative based on the
thiophene consumed. Removal of the volatile materials below
-40 °C is crucial to isolate 1 in pure form to prevent
decomposition in concentrated solution. For example, the
oxidation at -20 °C and removal of the solvent at -25 °C
afforded a 9:1 mixture of 1 and the dimerization product 2.3a,c
The dioxide 1 melted at about 6 °C with decomposition and
then solidified slowly on standing because of the formation of
dimerization and trimerization products (vide infra).8
Synthesis, Isolation, and Full Characterization of
the Parent Thiophene 1,1-Dioxide
Juzo Nakayama,* Hidehiro Nagasawa,
Yoshiaki Sugihara, and Akihiko Ishii
Department of Chemistry, Faculty of Science
Saitama UniVersity, Urawa, Saitama 338, Japan
ReceiVed June 12, 1997
Thiophene 1,1-dioxides are synthetically and theoretically
important compounds which act as 2π- or 4π-components in a
range of cycloadditions. A recent exhaustive literature survey
has revealed that more than 300 papers had appeared on the
chemistry of thiophene 1,1-dioxides.1,2 Among them, at least
33 papers have been concerned with the chemistry of the parent
thiophene 1,1-dioxide (1) theoretically or experimentally.3-5
However, despite such enormous efforts, 1 has eluded isolation
most likely as a result of a rapid cyclodimerization process.
Thus, most of the evidence for its existence comes from
chemical trapping experiments.3 We report here the synthesis,
isolation, and full characterization of 1.
Previously 1 was mainly generated by dehydrobromination
of 3-bromo-2,3-dihydrothiophene 1,1-dioxide.3a,b,p-r We have
examined the preparation of 1 by oxidation of thiophene with
dimethyldioxirane (DMD).6,7 Thus, a dilute solution of thiophene
in Me2CO was treated with DMD (3 equiv) at -20 °C for 36
h. The solvent and the unreacted DMD and thiophene were
removed thoroughly below -40 °C under reduced pressure,
The GCMS (EI, 70 eV) of 1 showed the molecular ion peak
at m/z 116 and the strongest peak at m/z 68 due to the furan
radical cation, and HRMS gave the satisfactorily results: calcd
for C4H4O2S 115.9932, found 115.9931. In the 1H NMR
spectrum (400 MHz) at -40 °C in CDCl3, the R- and
â-hydrogen signals appeared at δ 6.53-6.61 and 6.75-6.83 as
multiplets, respectively, whereas, for thiophene, these signals
appear as multiplets centered at δ 7.18 and 6.99, respectively.9
The above assignment was confirmed by comparison of the
spectra of 1 and 2-deuteriothiophene 1,1-dioxide prepared
separately.10 The 13C NMR spectrum (100.6 MHz) at -40 °C
showed two signals at δ 131.1 and 129.3, which were assigned
to the R- and â-carbons, respectively, by a C-H COSY
experiment.10,11 In the FTIR spectrum in CDCl3 solution, very
strong SO2 symmetric and asymmetric stretching absorptions
appeared at 1152 and 1306 cm-1, respectively; the latter signal
was accompanied by a weaker absorption at 1327 cm-1. In
the Raman spectrum, the strong sharp absorption due to the
CdC bond appeared at 1530 cm-1 and the strong absorptions
due to the SO2 moiety at 1151 cm-1 (sym) and 1305 cm-1
(asym). The UV spectrum in CHCl3 showed two absorption
maxima at 245 (ꢀ 870) and 288 (1070) nm.12
The half-life of 1 in solution depends on concentration. Thus,
the half-lives of 1 at 298 K were 137, 371, and 747 min for
0.12, 0.047, and 0.025 M CDCl3 solutions, respectively,
indicating that decomposition of 1 is not a unimolecular path.
In addition, the decomposition products depend on concentra-
tion. The decomposition in high dilute solution produces only
3, which comes from cyclodimerization followed by loss of SO2.
With increasing concentration of 1, trimerization product 4
begins to form. Thus, although decomposition product in 0.024
M CDCl3 solution is only 3, products of 0.20 M solution and
neat 1 were 3 and 4 in the ratios 1.0:0.36 and 1.0:1.5,
respectively. The 13C NMR of the trimer 4 showed six peaks
(1) Nakayama, J.; Sugihara, Y. In Organosulfur Chemistry (Synthetic
Aspects); Page, P. C. B, Ed.; Academic Press: New York, 1998, in press.
(2) (a) Rajappa, S. In ComprehensiVe Heterocyclic Chemistry; Bird, C.
W., Cheeseman, G. W. H., Eds.; Pergamon Press: Oxford, U.K., 1984;
Vol. 4, Chapter 3.14. (b) Rajappa, S.; Natekar, N. V. In ComprehensiVe
Heterocyclic Chemistry II; Bird, C. W., Ed.; Pergamon Press: Oxford, U.K.,
1996; Vol. 2, Chapter 2.10. (c) Raasch, M. S. In Thiophene and Its
DeriVatiVes; Gronowitz, S., Ed.; John Wiley: New York, 1985; p 571. (d)
Simpkins, N. S. Sulphones in Organic Synthesis; Pergamon Press: Oxford,
U.K., 1993; p 319.
(3) For generation and reactions (chemical trapping) of 1, see: (a) Backer,
H. J.; Melles, J. L. Proc. Koninkl. Nederland Akad. Wetenschap. 1951, 54B,
340. (b) Bailey, W. J.; Cummins, E. W. J. Am. Chem. Soc. 1954, 76, 1932.
(c) Bailey, W. J.; Cummins, E. W. J. Am. Chem. Soc. 1954, 76, 1936. (d)
Bailey, W. J.; Cummins, E. W. J. Am. Chem. Soc. 1954, 76, 1940. (e)
Procha´zka, M. Collect. Czech. Chem. Commun. 1965, 1158. (f) Reiter, S.
E.; Dunn, L. C.; Houk, K. N. J. Am. Chem. Soc. 1977, 99, 4199. (g) Copland,
D.; Leaver, D.; Menzies, W. B. Tetrahedron Lett. 1977, 639. (h) Patterson,
R. T. Diss. Abstr. Int. 1980, 41, 204-B. (i) Becker, J.; Wentrup, C.; Katz,
E.; Zeller, K.-P. J. Am. Chem. Soc. 1980, 102, 5110. (j) Zeller, K.-P.; Berger,
S. Z. Naturforsch. 1981, 36b, 858. (k) Albini, F. M.; Ceva, P.; Masherpa,
A.; Albini, E.; Caramella, P. Tetrahedron 1982, 38, 3629. (l) Molz, T.;
Ko¨nig, P.; Goes, R.; Gaugliz, G.; Meier, H. Chem. Ber. 1984, 117, 833.
(m) Meier, H.; Molz, T.; Kolshorn, H. Z. Naturforsch. 1984, 39b, 915. (n)
Bates, H. A.; Smilowitz, L.; Lin, J. J. Org. Chem. 1985, 50, 899. (o) Wetzel,
A.; Zeller, K.-P. Z. Naturforsch. 1987, 42b, 903. (p) Chou, T.-s, Hung, S.
C.; Tso, H.-H. J. Org. Chem. 1987, 52, 3394. (q) Chou, T.-s.; Chen, M.-
M. Heterocycles 1987, 26, 2829. (r) Chou, T.-s.; Chen, M.-M. J. Chin.
Chem. Soc. 1988, 35, 373. (s) Mu¨ller, P.; Schaller, J-.P. HelV. Chim. Acta
1989, 72, 1608. (t) Dent, B. R.; Gainsford, G. J. Aust. J. Chem. 1989, 42,
1307. (u) Frolov, P. A.; Kushnarev, D. F.; Iglamova, N. A.; Mazitova, F.
N.; Bazhenov, B. A.; Kalabin, G. A. Neftekhimiya 1990, 30, 556.
(4) For metal carbonyl complexes of 1, see: (a) Chow, Y. L.; Fossey,
J.; Perry, R. A. J. Chem. Soc., Chem. Commun. 1972, 501. (b) Eekhof, J.
H.; Hogeveen, H.; Kellogg, R. M.; Sawatzky, G. A. J. Organomet. Chem.
1976, 111, 349. (c) Albrecht, R.; Weiss, E. J. Organomet. Chem. 1990,
399, 163. (d) Albrecht, R.; Weiss, E. J. Organomet. Chem. 1991, 413, 355.
(e) Meier-Brocks, F.; Albrecht, R.; Weiss, E. J. Organomet. Chem. 1992,
439, 65.
(8) A DSC analysis showed an exothermic peak at about 8 °C when the
temperature was raised at a rate of 1 °C/min.
(9) Bird, C. W.; Cheeseman, G. W. H. In ComprehensiVe Heterocyclic
Chemistry; Bird, C. W., Cheeseman, G. W. H., Eds.; Pergamon Press:
Oxford, U.K., 1984; Vol. 4, Chapter 3.01.
1
(10) The previously reported H and 13C NMR data of 1,3m which was
generated by treatment of 3-bromo-2,3-dihydrothiophene 1,1-dioxide with
Et3N, are not in harmony with the present data. It was reported that R- and
â-hydrogen signals appeared at δ 6.64 and 6.38, respectively, as multiplets
in CDCl3. These chemical shift values differ from ours and at least the
assignment should be reversed. In addition, reportedly, the 13C NMR
spectrum showed only one signal in C6D6 at δ 131.0 because of accidental
overlapping of CR and Câ signals, which appeared as a broad signal at δ
129.1 in CDCl3.
(5) For theoretical study on 1, see: (a) Fortina, L.; Montaudo, G. Gazz.
Chim. Ital. 1960, 987. (b) Lert, P. W.; Trindle, C. J. Am. Chem. Soc. 1971,
93, 6392. (c) de Jong, F.; Janssen, M. J. Chem. Soc., Perkin Trans. 2, 1972,
572. (d) de Jong, F.; Janssen, M. Rec. TraV. Chim. Pays-Bas 1973, 92,
1073. (e) de Jong, F; Noorduin, A. J.; Bouwman, M. T.; Janssen, M. J.
Tetrahedron Lett. 1974, 1209. (f) Rozas, I. J. Phys. Org. Chem. 1992, 5,
74. (g) Jursic, B. S. J. Heterocycl. Chem. 1995, 32, 1445.
(6) Adam, W.; Hadjiarapoglou, L.; Smerz, A. Chem. Ber. 1991, 124,
227.
(7) Miyahara, Y.; Inazu, T. Tetrahedron Lett. 1990, 31, 5955.
(11) For thiophene, R- and â-carbon signals appear at δ 125.6 and 127.3,
respectively.9
(12) It was reported that 1 showed absorptions at 220 (ꢀ 2010), 254 (450),
3b
and 289 nm (1230) in CHCl3 and at 220 (ꢀ 2000) and 289 nm (880) in
MeOH.3e
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