Synthesis of 1H-2,3-dihydropyrrolizine derivatives as precursors of bifunctional alkylating agents

Two 1H-2,3-dihydropyrrolizine derivatives bearing a nitro group at the 6 position have been synthesized and an improved method for nitrating pyrroles using potassium nitrate in trifluoroacetic acid was developed. An efficient, two-step synthesis of the butterfly pheromone, Danaidone, was also developed with an overall 33% yield.