179. Synthesis of pyrrolidines and pyrrolizidines with α-pseudoquaternary centers by Cu-catalyzed condensation of α-diazodicarbonyls and aryl γ-lactams
     Sébastien Goudedranche, Céline Besnard, Léo Egger, Jérôme Lacour
     Angew. Chem. Int. Ed. 2016, 55, 13775-13779

Under copper-catalysis exclusively, N-aryl γ-lactams react intermolecularly with acceptor-acceptor diazo reagents, usually dicarbonyls, to yield functionalized pyrrolidines carrying α-pseudoquaternary centers. Thanks to preferred [1,2]-migrations of acyl or phosphoryl groups, single regioisomers are obtained. Furthermore, in the presence of a Lewis acid, subsequent Friedel-Crafts reactions occur yielding tricyclic pyrrolizidines in excellent yields (90-96%) and diastereoselectivity (up to and higher than 20:1).

DOI : 10.1002/anie.201607574 

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