Heterocyclisch anellierte Indolizine durch intramolekulare [3 + 2]-Cycloaddition mit Nicotinium-dicyanmethyliden

Heterocyclically Annulated Indolizines by Intramolecular [3 + 2]-Cycloaddition with Nicotinium-dicyanomethylides Thermally induced intramolecular [3 + 2] cycloaddition reactions of the nicotinium dicyanomethylides 4a - c , containing different ω-alkyne sidechains as substiuents at the pyrrolidine nitrogen, lead to the corresponding novel, heterocyclically annulated indolizines 6 - 8 in high yields. The dicyanmethylide 9 bearing an activated side chain dipolarophile yields the naph-thyridine 14 in small amounts besides the indolizine 11 .