Cyclization reactions of homopropargyl azide derivatives catalyzed by PtCl4 in ethanol solution: synthesis of functionalized pyrrole derivatives.

[Structure: see text] PtCl4-catalyzed cyclization reactions of homopropargyl azide derivatives to pyrrole rings were investigated. Using ethanol as solvent with 2,6-di-tert-butyl-4-methylpyridine as the base was found to be the best set of conditions for effecting this ring-closing reaction. These reaction conditions can be applied to the preparation of functionalized pyrrole derivatives, with no effect on the functional groups.