Zur Reaktion von Cyclopropenonen mit Azomethinen; VII. Diphenylcyclopropenon und cyclische Amidine: Synthese von bi- und tricyclischen Pyrrolinon-Derivaten
pyrrolizidines and indolizidines, respectively, each with a hydroxy group on the carbon atom at the bridgehead. The cyclopropenone functions as an all-carbon 1,3-dipole equivalent towards the cyclic imine in this reaction, and the cyclic imines used include polyhydroxylated systems, thus allowing access to australine, alexine and hyacinthacine type compounds. The pyrrolizidine products contain the core of the