Synthesis of Pyrrolidines and Pyrrolizidines with α-Pseudoquaternary Centers by Copper-Catalyzed Condensation of α-Diazodicarbonyl Compounds and Aryl γ-Lactams.

N-aryl γ-lactams react intermolecularly with acceptor-acceptor diazo reagents, usually dicarbonyl compounds, in a copper-catalyzed process to yield functionalized pyrrolidines with α-pseudoquaternary centers. As 1,2-acyl or -phosphoryl migration is preferred, single regioisomers are obtained. Furthermore, in the presence of a Lewis acid, subsequent Friedel-Crafts reactions yield tricyclic pyrrolizidines in excellent yields (90-96 %) and diastereoselectivities (up to >20:1).