An anomalous Dakin–West reaction of N-carbamate substituted prolines and trifluoroacetic anhydride

Abstract

A novel transformation of N-alkoxycarbonylprolines 1 to 4-trifluoroacetyl-2,3-dihydropyrroles 2 was efficiently realized by utilizing trifluoroacetic anhydride, in which probable intermediates were mesoionic 1,3-oxazolium-5-olates B.

References

1. G. L. Buchanan, Chem. Soc. Rev., 1988, 17, 91.
2. M. Kawase, H. Miyamae, M. Narita and T. Kurihara, Tetrahedron Lett., 1993, 34, 859; M. Kawase, Heterocycles, 1993, 36, 2441.
3. M. Kawase, Tetrahedron Lett., 1994, 35, 149.
4. M. Kawase, S. Saito, H. Kikuchi and H. Miyamae, Heterocycles, 1997, 45, 2185.
5. M. Kawase, Chem. Pharm. Bull., 1997, 45, 1248.
6. T. S. Kaufman, V. L. Ponzo and J. Zinczuk, Org. Prep. Proced. Int., 1996, 28, 487 and references cited therein.
7. Full details of the D–W reaction of N-alkoxycarbonyl-N-alkyl-α-amino acids will be reported elsewhere.
8. R. Wilder and S. Mobashery, J. Org. Chem., 1992, 57, 2755; H. Collet, C. Bied, L. Mion, J. Tailades and A. Commeyras, Tetrahedron Lett., 1996, 37, 9043 and references cited therein.
9. K. T. Potts, D. Bhattacharjee and S. Kanemasa, J. Org. Chem., 1980, 45, 4985.
10. G. A. Kraus and K. Neuenschwander, J. Org. Chem., 1981, 46, 4791; Y. Nomura, K. Ogawa, Y. Takeuchi and S. Tomoda, Chem. Lett., 1977, 693.
11. T. Nishio, C. Kashima and Y. Omote, J. Synth. Org. Chem. Jpn., 1976, 34, 526; J. V. Greenhill, Chem. Soc. Rev., 1977, 6, 277.