Collect. Czech. Chem. Commun. 1994, 59, 2641-2649

Phenanthridinium-Based Azomethine Ylides in 1,3-Dipolar Cycloaddition with Dimethyl Acetylenedicarboxylate

Milan Potáčeka, Tomáš Topinkaa, Jiří Dostálb and Jaromír Marekc

a Department of Organic Chemistry, Masaryk University, 611 37 Brno, Czech Republic
b Department of Biochemistry, Masaryk University, 662 43 Brno, Czech Republic
c Department of Inorganic Chemistry, Masaryk University, 611 37 Brno, Czech Republic


Azomethine ylides generated from 5-(alkoxycarbonylmethyl) phenanthridinium cations I were used in the 1,3-dipolar cycloadditions with dimethyl acetylenedicarboxylate as dipolarophile. The cycloadducts II were found to be very unstable species and readily oxidized to fully aromatic pyrrolo[1,2-f]phenanthridines III. Their structure was compared with the compounds formed by the oxidation of cycloadducts IV of the same ylide with dimethyl fumarate and maleate. In both cases pyrrolines V were found as intermediates. The structure of the products was determined by NMR and MS as well as by X-ray analysis.