Domino reactions of 4,5-dicyanopyridazine with dihydroheterocycles: synthetic and mechanistic features.
The title pyridazine 1 was found to react with both 2,3-dihydrofuran (2) and 3,4-dihydro-2H-pyran (9) to give the tetracyclic skeletons 5-8 and the phthalonitrile 12 through the intermediates 4 and 10, respectively. A more complex mechanism was ascertained for the reaction of 1 with the pyrroline 14 which, under suitable conditions, afforded the bicyclic derivative 19 as the predominant product; selective elaborations of this species into the 5,6-dicyanoindoles 22 and 23 are reported.
Giomi
Donatella
D
Dipartimento di Chimica Organica Ugo Schiff, Polo Scientifico, Università di Firenze, Via della Lastruccia 13, I-50019 Sesto Fiorentino, Florence, Italy. donatella.giomi@unifi.it
Cecchi
Marco
M