Some Applications of Zirconium(IV) Tetrachloride (ZrCl4) and Zirconium(IV) Oxydichloride Octahydrate (ZrOCl2.8H2O) as Catalysts or Reagents in Organic Synthesis
H. Firouzabadi* and M. Jafarpour
Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71454, Iran
Both ZrCl4 and ZrOCl2.8H2O are commercially available solid chemicals. Due to their low toxicities (LD50 [ZrCl4 oral rate] = 1688 mg/kg), (LD50 [ZrOCl2.8H2O oral rate] = 2950 mg/kg), low costs, ease of handling, high activity, the zirconium(IV) compounds are potential green catalysts or reagents which are of importance from different views. In this review we have paid attention to the applications of these compounds as reagents or catalysts in Friedel-Crafts reactions, Fries rearrangements, reduction and oxidation reactions, cycloaddition and hydrometalation reactions, protection and deprotection of functional groups, reactions of epoxides, iodination of alcohols, S-alkylation of thiols with alcohols, Michael addition, condensation of indoles with carbonyl compounds, Claisen ester condensation, Baylis-Hillman reaction, preparation of organozirconium compounds and some other miscellaneous reactions.
Keywords: ZrCl4 and ZrOCl2.8H2O, Friedel-Crafts reaction, Fries rearngement, Reduction, oxidation, cycloaddition, and hydrometalation, Michael addition, Claisen condensation, Baylis-Hillman reaction