Iron-catalyzed olefin cis-dihydroxylation by H2O2: electrophilic versus nucleophilic mechanisms.
Previous studies have classified a series of nonheme iron catalysts for olefin cis-dihydroxylation by H2O2 into two groups. Complex 1, [(TPA)Fe(OTf)2], representative of Class A catalysts, forms a low-spin FeIII-OOH intermediate that gives rise to a high-valent FeV(=O)OH oxidant. The preference of this catalyst for electron-rich olefins demonstrates its electrophilic character. On the other hand, complex 2, [(6-Me3-TPA)Fe(OTf)2], representative of Class B catalysts, prefers instead to oxidize electron-deficient olefins, suggesting an oxidant with nucleophilic character. It is suggested that such a nucleophilic oxidant may be the high-spin FeIII-OOH intermediate derived from 2 or the FeIV(=O)(*OH) species derived therefrom.
Fujita
Megumi
M
Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN 55455, USA.
Costas
Miquel
M
Que
Lawrence
L
D000438:Alcohols / Q000138:chemical synthesis*; D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D005290:Ferric Compounds / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D006900:Hydroxylation; D010084:Oxidation-Reduction
D000438:Alcohols; D000475:Alkenes; D005290:Ferric Compounds; D006861:Hydrogen Peroxide