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Efficient Synthesis of Heterocycles with the Aid of Electrophilic Cyclizations and Fluorous Chemistry. Roman Dembinski, Department of Chemistry, Oakland University.
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Efficient Synthesis of Heterocycles with the Aid of Electrophilic Cyclizations and Fluorous Chemistry Roman Dembinski, Department of Chemistry, Oakland University Ligand-free 5-endo-dig cyclization of 1,4- and 1,2,4-substituted but-3-yn-1-yl (homopropargyl) azides in the presence of zinc chloride (usually 20 mol %) in dichloroethane at elevated temperature provides 2,5-di- and 2,3,5-trisubstituted pyrroles in high to moderate yields (91-41%). Both conventional and microwave protocols furnished comparable results. A structure of 2-(4-fluorophenyl)-5-(4-methylphenyl)-1H-pyrrole was confirmed by X-ray crystallography.