Synthesis of tetrasubstituted N-alkoxypyrroles from reaction of -oximino ketones, dialkylacetylendicarboxylates and trialkylphosphites via intramolecular Wittig reaction

The protonated reactive 1:1 adduct generated from reaction of dialkyl acetylendicarboxylates and trialkylphosphites by ?-oximinoketones leads to vinyltrialkoxy phosphonium salts, which endure intramolecular Wittig reaction to produce dialkyl 1-alkoxypyrrole dicarboxylates in good yields.