Exploring γ‑Nitroketones as 1,4-Dicarbonyl Precursors for Annulation to Pyridazines through Interrupted Nef Reaction

A practical approach toward pyridazine synthesis has
been realized
by exploring an interrupted Nef reaction strategy using a combination
of sulfur and hydrazine. The access to pyridazine was accomplished
through a challenging 1,4-dicarbonyl intermediate through umpolung
of γ-nitro ketones under milder conditions. Sulfur was shown
to facilitate access to a 1,4-dicarbonyl equivalent. The presented
methodology represents a broadly applicable solution to achieve a
challenging 1,4-dicarbonyl intermediate using a precursor.