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

Ehrlich reagent

Variety of products

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.

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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. 1994, 59,579. G. R. Geier III, D. M. Haynes, J. S. Lindsey Org. Lett. 1999, 1, 1455.

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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.

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.

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

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