1. Reaction of pyrrole with aldehydes – a mysterious story
Daniel T. Gryko
Institute of Organic Chemistry of the Polish Academy of Sciences
Warsaw, Poland

2. Ehrlich reagent

3. Variety of products

4. Complexity
Fig. 1 A representative LD-MS spectrum from a crude oxidized reaction mixture of pyrrole + benzaldehyde (100 mM pyrrole + benzaldehyde, 10 mM BF3–Et2O, CH2Cl2, room temperature, 2 min). The oligomer length (n) is given by the number above the symbol. The yield of TPP (UV–Vis) is noted.

5. Rothemund P. Rothemund J. Am. Chem. Soc. 1935, 57, 2010.
P. Rothemund, A. R. Menotti J. Am. Chem. Soc. 1941, 63, 267.

6. Adler
A. D. Adler, F. R. Longo, W. Shergalis J. Am. Chem. Soc. 1964, 86, 3145.
A. D. Adler, F. R. Longo and co-workers J. Org. Chem. 1967, 32, 476.

7. Lindsey
J. S. Lindsey, I. C. Schreiman, H. C. Hsu, P. C. Kearney et al J. Org. Chem , 52, 827.
G. R. Geier III, J. A. Riggs, J. S. Lindsey JPP 2001, 5,681.

8. Lindsey
J. S. Lindsey, I. C. Schreiman, H. C. Hsu, P. C. Kearney et al J. Org. Chem , 52, 827.

9. Lindsey-salts No correlation with cations.
No correlation with desiccative power.
Reversible or not???
F. Li, K. Yang, J. S. Tyhonas, K. A. MacCrum, J. S. Lindsey Tetrahedron 1997, 53,

10. Lindsey-salts
F. Li, K. Yang, J. S. Tyhonas, K. A. MacCrum, J. S. Lindsey Tetrahedron 1997, 53,

11. Lindsey-deep
G. R. Geier III, J. S. Lindsey Org. Lett. 2000, 2, 1745.

12. Lindsey-st. hind.
J. S. Lindsey, R. W. Wagner J. Org. Chem , 54, 828.

13. Trans-A2B2-porphyrins
J. S. Lindsey, R. W. Wagner J. Org. Chem , 64, 2864.
D. T. Gryko, M. Tasior, Tetrahedron Lett. 2003, 44, 3317.

14. Gas phase
C. M. Drain, X. Gong Chem. Commun , 2117.

15. Gas phase-2
C. M. Drain, et al. J. Porphyrins Phthalocyanines , 14, 621.

16. Oxidative Lewis Acids
E. F. LLama and co-workers J. Chem. Soc. Perkin , 2611.

17. In phenols
G. A. Mirafzal, H. M. Bosse, J. M. Summer Tetrahedron Lett , 40, 623.

18. In micelles
R. P. Bonar-Law J. Org. Chem 1996, 61, 3623.

19. Rocha-Gonzalves
M. d’A. Rocha Gonzalves and co-workers J. Het. Chem , 22, 931.

20. Rocha-Gonzalves
M. d’A. Rocha Gonzalves and co-workers Heterocycles 1996, 43, 1423.
M. d’A. Rocha Gonzalves and co-workers JPP, 2007, 11,

21. Sharghi H. Sharghi, A. H. Nejad Helv. Chim. Acta 2003, 86, 408.
H. Sharghi, A. H. Nejad Tetrahedron 2004, 60, 1863.

22. Krausz P. Krausz et al. J. Porphyrins Pkthalocyanines 2006, 10, 937.
P. Krausz et al. Tetrahedron Lett. 2008, 49, 5537.

23. Furuta/Lotos
L. Latos-Grażyński and co-workers Angew. Chem. Int. Ed , 33, 779.
H. Furuta, H. Osano, T. Ogawa J. Am. Chem. Soc. 1994, 116, 767.

24. Lindsey N-confused
G. R. Geier III, J. S. Lindsey J. Org. Chem. 1999, 64, 1596.
J. S. Lindsey, K. A. MacCrum, J. S. Tyhonas, Y.-Y. Chuang J. Org. Chem , 59,579.
G. R. Geier III, D. M. Haynes, J. S. Lindsey Org. Lett. 1999, 1, 1455.

25. Lindsey N-confused
G. R. Geier III, D. M. Haynes, J. S. Lindsey Org. Lett. 1999, 1, 1455.

26. Cavaleiro
J. A. S. Cavaleiro and coworkers Chem. Commun. 1999, 385.

27. Cavaleiro
J. A. S. Cavaleiro and coworkers Chem. Commun. 1999, 385.

28. Osuka-1
J.-Y. Shin, H. Furuta, K. Yoza, S. Igarashi, A. Osuka J. Am. Chem. Soc. 2001, 123, 7190.

29. Osuka-2
J.-Y. Shin, H. Furuta, K. Yoza, S. Igarashi, A. Osuka J. Am. Chem. Soc. 2001, 123, 7190.
S. Shimizu, J.-H. Shin, H. Furuta, R. Ismael, A. Osuka Angew. Chem. Int. Ed , 42, 78.

30. Who was first?
N. M. Loim and co-workers Izv. Akad. Nauk. Ser. Khim. 1994, 5, 925.
E. Rose and co-workers J. Am. Chem. Soc. 1996, 118, 1567.
L. Latos-Grażyński and co-workers New J. Chem. 1997, 21, 691.

31. No catalyst…
G. I. Zhungietu, F. N. Chukhrii Zh. Vses. Khim. Obshchest. 1970, 15, 586.
T. Severin, I. Ipach Chem. Ber. 1975, 108, 1768.
S. P. Ivonin, A. V. Lapandin, A. A. Anishchenko Synth. Comm. 2004, 34, 451.

32. With base…
S. Taniguchi and co-workers Synlett 1999, 73.

33. Summary We utilize the reaction which we do not understand
More accidental than rational development
Probably still at the early stage