Organocatalysis by an aprotic imidazolium zwitterion: regioselective ring-opening of aziridines and applicable to gram scale synthesis.

An imidazole-based zwitterionic-salt, 4-(3-methylimidazolium)butane sulfonate (MBS), has been found to be an efficient organocatalyst for aziridine ring-opening regioselectively by various nucleophiles like indoles, pyrroles, methanol, ethanol, acetic acid and di-iso-propylamine. The reactions are highly regioselective and they always afford the products resulting from benzylic attack. The present methodology is applicable to gram scale synthesis. [ABSTRACT FROM AUTHOR]