Stereoselective Synthesis of endo-7-Halo-3-Oxo-2-Azabicyclo[4.1.0]Heptanes by Reductive Hydrodehalogenation of gem-Dihalocyclopropanes

The reduction of 7-gem-dihalo-3-oxo-2-azabicyclo[4.1.0]heptanes with metallic zinc yielded stereoselective synthesis of novel heterocyclic endo-7-halo-3-oxo-2-azabicyclo[4.1.0]heptanes in good to high yields without any evidence for the formation of corresponding exo-isomers. The prepared heterocyclic compounds were characterized by various techniques and their stereochemistry was established on the basis of the values of the coupling constants for H-1, H-5, H-6 and H-7 by recording homonuclear spin-spin decoupled 1H NMR spectra. The developed protocol has many advantages such as simple reaction conditions, lower cost, high yields, and selective synthesis of novel heterocyclic cyclopropyl compounds present in a large number of biologically active natural products and pharmaceuticals compounds.