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.