The synthesis of nitrogen heterocycles via the intramolecular Khand reaction: formation of tetra- and hexa-hydrocyclopenta[c]pyrrol-5(1H)-ones and hexahydro-6H-2-pyrindin-6-ones

Abstract

Azabicyclo[3.3.0]octenones and azabicyclo[4.3.0]nonenones have been obtained by cyclisation of hexacarbonyldicobalt complexes of aza-heptenynes and -octenynes respectively. An unusual feature of the cyclisation of N-acyl-4-azahept-1-en-6-ynes is the extensive formation of the reduced products, N-acyl-3-azabicyclo[3.3.0]octan-7-ones under most reaction conditions.