An unusual bicyclic aziridine, 1-azabicyclo[4.1.0]heptan-2-one, and its reaction with nucleophiles

Unexpected reaction pathways have been unravelled that are involved in the generation of 2,2,5,5-substituted tetrahydrofurans from the mesylate of 5-hydroxy-5-methyl-6-oxo-2-phenyl-2-piperidinemethanol (). Upon treatment of with amines under controlled conditions two reactive intermediates could be isolated. The first is a strained aziridine-fused lactam, 1-azabicyclo[4.1.0]heptan-2-one , which reacts further with amines or methoxide at the lactam carbonyl group to form γ-hydroxyalkylaziridines. Final N-acylation results in internal OH attack to give the hydrofuran products. Reaction of with some other nucleophiles led to 3,3,6,6-substituted 2-piperidinones.