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Chemicals >> Oxidizing Agents

Ruthenium(III-VII) compounds

RuCl3 - the most used reagent - is used mainly catalytically in oxidation reactions. By means of stoichiometric quantities of an oxidizing agent such as Oxone or NaIO4 it is oxidized in catalytic cycles to ruthenium tetroxide. RuO4 reacts similar to OsO4, but with a smaller efficiency. However, the use of Ru compounds as reagents is clearly cheaper.

See also: TPAP

Recent Literature

An improved protocol for the RuO4-catalyzed syn-dihydroxylation uses only 0.5 mol% catalyst under acidic conditions. Various olefins can be hydroxylated in good to excellent yields with only minor formation of side products.
B. Plietker, M. Niggemann, Org. Lett., 2003, 3353-3356.

An efficient oxidant-free oxidation for a wide range of alcohols was achieved by a recyclable ruthenium catalyst, which was prepared from readily available reagents through nanoparticle generation and gelation.
W.-H. Kim, I. S. Park, J. Park, Org. Lett., 2006, 8, 2543-2545.

Specific oxidation protocols have been developed for the cleavage of styrenes, aliphatic olefins, and terminal aliphatic olefins to carbonyl compounds with ruthenium trichloride as catalyst. Olefins that are not fully substituted are converted to aldehydes rather than carboxylic acids.
D. Yang, C. Zhang, J. Org. Chem., 2001, 66, 4814-4818.

A catalytic amount of a composite material, RuO2/BaTi4O9, in combination with NaIO4 in EtOAc-H2O has been shown to efficiently cleave alkenes, affording ketones, aldehydes and/or carboxylic acids in high yields.
H. Okumoto, K. Ohtsuko, S. Banjoya, Synlett, 2007, 3201-3205.

D. Yang, C. Zhang, J. Org. Chem., 2001, 66, 4814-4818.

A new mild RuO4-catalyzed ketohydroxylation of olefins is reported. α-Hydroxy ketones were obtained with high regioselectivity and in good to excellent yields.
B. Plietker, J. Org. Chem., 2003, 68, 7123-7125.

A two-step sequence of asymmetric dihydroxylation and regioselective monooxidation gave enantiopure α-hydroxy ketones (acyloins). The combination of RuCl3/Oxone/NaHCO3 was used in the first catalytic regioselective oxidation of vic-diols to α-ketols.
B. Plietker, Org. Lett., 2004, 6, 289-291.

An efficient method for the oxidative cleavage of internal and terminal alkynes to carboxylic acids using a combination of RuO2/Oxone/NaHCO3 in a CH3CN/H2O/EtOAc solvent system is described. Various alkynes, regardless of their electron density, were oxidized to carboxylic acids in excellent yield.
D. Yang, F. Chen, Z.-M. Dong, D.-W. Zhang, J. Org. Chem., 2004, 69, 209-212.

A highly enantioselective and catalytic vinylation of aldehydes leads to allylic alcohols that are then transformed to the allylic amines via Overman's [3,3]-sigmatropic rearrangement of imidates. Oxidative cleavage of the allylic amines furnishes amino acids in good yields and excellent ee's. The scope and utility of this method are demonstrated by the synthesis of challenging allylic amines and their subsequent transformation to valuable nonproteinogenic amino acids, including both D and L configured (1-adamantyl)glycine.
Y. K. Chen. A. E. Lurain, P. J. Walsh, J. Am. Chem. Soc., 2002, 124, 12225-12231.

RuCl3-catalyzed oxidative cyanation of tertiary amines with sodium cyanide under molecular oxygen at 60C gives the corresponding α-aminonitriles in excellent yields. This reaction is clean and should be an environmentally benign and useful process.
S.-I. Murahashi, N. Komiya, H. Terai, T. Nakae, J. Am. Chem. Soc., 2003, 125, 15312-15313.

A novel, high-yielding method for sulfation of alcohols proceeds via sulfite- and sulfate diester intermediates. Sulfite diesters serve as versatile sulfate monoester precursors, that allow interesting transformations.
M. Huibers, I. Manuzi, F. P. J. T. Rutjes, F. L. van Delft, J. Org. Chem., 2006, 71, 7473-7476.

A facile ruthenium-catalyzed methodology for the preparation of pentavalent iodine compounds uses peracetic acid as an oxidant. The new procedure allows the preparation of iodylarenes bearing strongly electron-withdrawing groups.
A. Y. Koposov, R. R. Karimov, A. A. Pronin, T. Skrupskaya, M. S. Yusubov, V. V. Zhdankin, J. Org. Chem., 2006, 71, 9912-9914.