Nine new helical compounds were synthesized using a one-pot reaction between phenanthrolinium N-ylides and quinones as cyclic olefinic dipolarophiles. 1,4-naphthoquinone, 1,4-benzoquinone and 1,2-naphthoquinone were used as dipolarophiles, resulting in excellent to moderate yields. The structure of the compounds was deduced using NMR spectroscopy and the helical distortion was ascertained using X-ray analysis.

Although a relatively simple system, pyrrolo[1,2-b]pyridazines have been subject to numerous studies and synthetic attempts. The present review represents an update to the 1976 review of Kuhla and Lombardino.