Ruthenium trichloride, alcohol oxidant

Sodium hypochlorite is used for the epoxidation of double bonds [659, 691] for the oxidation of primary alcohols to aldehydes [692], of secondary alcohols to ketones [693], and of primary amines to carbonyl compounds [692] for the conversion of benzylic halides into acids or ketones [690] for the oxidation of aromatic rings to quinones [694] and of sulfides to sulfones [695] and, especially, for the degradation of methyl ketones to carboxylic acids with one less carbon atom [655, 696, 697, 695, 699] and of a-amino acids to aldehydes with one less carbon [700]. Sodium hypochlorite is also used for the reoxidation of low-valence ruthenium compounds to ruthenium tetroxide in oxidations by ruthenium trichloride [701]. 

Sodium bromate, NaBrOs, a white crystalline compound, converts acyloins into a-diketones under forcing conditions [740]. More often, this reagent is used as a reoxidant of ammonium cerium nitrate [421], cerium sulfate [741], or ruthenium trichloride [741] in oxidations of alcohols to aldehydes [421] or carboxylic acids [741]. 

Potassium ruthenate, K2RUO4, is prepared in situ from ruthenium trichloride and aqueous persulfate. The reagent catalyzes persulfate oxidations of primary alcohols to acids, secondary to ketones, and primary amines to nitriles or acids at room temperature in high yields [196],... 

The oxidation of alcohols with ruthenium tetroxide prepared by oxidation of ruthenium trichloride hydrate with sodium bromate takes place at room temperature. However, aldehydes may undergo further oxidation to carboxylic acids [940]. 

High yields of ketones result from the gentle oxidation of alcohols with compounds of ruthenium. Ruthenium tetroxide oxidizes cyclohexanol to cyclohexanone in carbon tetrachloride at room temperature in 93% yield [940], Instead of the rather expensive ruthenium tetroxide, which is required in stoichiometric amounts, catalytic amounts of ruthenium trichloride may be used in the presence of sodium hypochlorite as a reoxidant with the same results [701]. Sodium ruthenate [937] and potassium ruth-enate [196], which are prepared from ruthenium dioxide and sodium periodate in sodium hydroxide and from ruthenium trichloride and potassium persulfate, respectively, also effect oxidations to ketones at room temperature. 

Besides ruthenium tetroxide, other ruthenium salts, such as ruthenium trichloride hydrate, may be used for oxidation of carbon-carbon double bonds. Addition of acetonitrile as a cosolvent to the carbon tetrachloride-water biphase system markedly improves the effectiveness and reliability of ruthenium-catalyzed oxidations. For example, RuCl3 H20 in conjunction with NaI04 in acetonitrile-CCl4-H20 oxidizes (Ej-S-decene to pentanoic acid in 88% yield. Ruthenium salts may also be employed for oxidations of primary alcohols to carboxylic acids, secondary alcohols to ketones, and 1,2-diols to carboxylic acids under mild conditions at room temperature, as exemplified below. However, in the absence of such readily oxidized functional groups, even aromatic rings are oxidized. 

An alternative protocol for the ruthenium tetroxide oxidation of alcohols uses sodium perbromate to generate the reagent ijn situ from ruthenium trichloride in a chloroform - phosphate... 

Another alkene cleavage method is illustrated by the conversion of the alcohol moiety in 5.228 (the template) to a mesylate and then to azide 5.229. Oxidative cleavage with periodate and ruthenium trichloride was followed by hydrogenation of the azide to give 3-amino-2-methylpentanoic acid, 5.230. 

Ruthenium trichloridelsodium hypochlorite Oxidations with ruthenium trichloride-hypochlorite Ketones from sec. alcohols Oxidative elimination of phenyl groups... 

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