Formation of thioketenes by thermal fragmentation of 1,2-dithiol-3-ones

Abstract

Thioketenes 6 are formed in a Wolff-type rearrangement together with OCS by flash vacuum thermolysis (FVT) of 1,2-dithiol-3-ones 4 and identified by a combination of Ar matrix isolation FTIR sepctroscopy and collisional activation mass spectrometry (CAMS). The thioketenes all have strong IR absorptions in the 1750 cm^-1 region ascribed to the C=C=S stretching vibration. The matrix IR and the CAMS of thioketenes 6a, 6d and 6e are identical with those of authentic samples generated by FVT of 1,2,3-thiadiazoles 7a, 7d and 2,3-dihydrobenzothiophene-2,3-dione 9, respectively. A competing fragmentation of the dithiolones leads to the corresponding acetylenes. CO and S₂ were also identified.

References

1. G. Seybold and C. Heibl, Angew. Chem., Int. Ed. Engl., 1975, 14, 248; Chem. Ber., 1977, 110, 1225.
2. (a) E. Schaumann, Tetrahedron, 1988, 44, 1827; (b) E. Schaumann, in Houben-Weyl, Metoden der Organischen Chemie, ed. D. Klamann, Thieme, Stuttgart, 1985, vol. E11/1, p. 232.
3. C. O. Kappe, C. Th. Pedersen, J.-M. Catel and Y. Mollier, J. Chem. Soc., Perkin Trans. 2, 1994, 351.
4. (a) M. W. Wong, C. Wentrup and R. Flammang, J. Phys. Chem., 1995, 99, 16 849; (b) C. Th. Pedersen, Tetrahedron Lett., 1996, 32, 4805.
5. H. Egsgaard and L. Carlsen, J. Chem. Res., 1991, 226.
6. Ar matrix FTIR spectra of authentic samples of CO, CS₂, phenylacetylene and diphenylacetylene were recorded for comparison.
7. G. C. Pimentel and S. W. Charles, Pure Appl. Chem., 1963, 7, 111.
8. H. Bender, F. Carnovale, J. B. Peel and C. Wentrup, J. Am. Chem. Soc., 1988, 110, 3458; C. Wentrup, S. Fischer, A. Maquestiau and R. Flammang, J. Org. Chem., 1986, 51, 1908.
9. C. Wentrup, H. Bender and G. Gross, J. Org. Chem., 1987, 52, 3838; C. O. Kappe, M. W. Wong and C. Wentrup, J. Org. Chem., 1995, 60, 1686.
10. J. Møller and C. Th. Pedersen, Acta Chem. Scand., 1968, 22, 706.
11. M. Torres, A. Chement, J. E. Bertie, H. E. Gunning and O. P. Strausz, J. Org. Chem., 1978, 43, 2490.
12. A. Krantz and J. Laureni, J. Am. Chem. Soc., 1981, 103, 486.
13. C. Wentrup, R. Blanch, H. Briehl and G. Gross, J. Am. Chem. Soc., 1988, 110, 1874.
14. J. Brown, R. Flammang, Y. Govaert, M. Plisnier, C. Wentrup and Y. Van Haverbeke, Rapid. Commun. Mass Spectrom., 1992, 6, 249; R. H. Bateman, J. Brown, M. Lefevere, R. Flammang and Y. Van Haverbeke, Int. J. Mass Spectrom. Ion Processes, 1992, 115, 205.
15. F. Boberg and J. Knoop, Liebigs Ann. Chem., 1967, 708, 148.
16. R. Mayer and J. Faust, Chem. Ber., 1963, 96, 2702.
17. W. Kirmse and L. Horner, Liebigs Ann Chem., 1958, 614, 4.
18. C. D. Hurd and R. I. Mori, J. Am. Chem. Soc., 1955, 77, 5359.