Alkyl hydroperoxide, from carboxylic acids

Saponification of alkyl peroxyesters yields alkyl hydroperoxides and carboxylic acids or their alkali metal salts. a-Ether-substituted peroxides can be hydrolyzed to the unsubstituted alkyl hydroperoxides, eg, tert-huty hydroperoxide from tert-huty 2-oxacyclohexyl peroxide [28627-46-5] (62) ... 

A hydroxymethyl group can be introduced (ArH —> ArCH20H) by several variations of this method. Alkylation of these substrates can also be accomplished by generating the alkyl radicals in other ways from hydroperoxides and FeS04, from alkyl iodides and H2O2—Fe V from carboxylic acids and lead tetraacetate, or from the photochemically induced decarboxylation of carboxylic acids by iodoso-benzene diacetate. 

Alkyl radicals for such reactions are available from many sources such as acyl peroxides, alkyl hydroperoxides, particularly by the oxidative decarboxylation of carboxylic acids using peroxy-disulfate catalyzed by silver. Pyridine and various substituted pyridines have been alkylated in the 2-position in high yield by these methods. Quinoline similarly reacts in the 2-, isoquinoline in the 1-, and acridine in the 9-position. Pyrazine and quinoxaline also give high yields of 2-substituted alkyl derivatives <74AHC(16)123). 

It has been proposed that the crucial step of the oxidation by the reagent O2 - H2O2 - VOj"- pyrazine-2-carboxylic acid is the very efficient generation of HO radicals [15]. These radicals abstract a hydrogen atom from the alkane, RH, to generate the alkyl radical, R. The latter reacts rapidly with an O2 molecule affording the peroxo radical, ROO. This radical is then transformed simultaneously into three products alkyl hydroperoxide, ketone, and alcohol. The relative content of the last two products is increased if the reaction temperature is higher. 

Recently, we have developed a versatile aqueous medium self-assembly method for the generation of diverse multicopper(II) complexes and coordination polymers derived from cheap and commercially available ligands such as aminoalcohols and benzenecarboxylates [6-15]. The obtained compounds were applied as highly efficient and versatile catalysts or catalyst precursors in two different alkane functionalization reactions. These include the mild oxidation of alkanes (typically cyclohexane as a model substrate) by hydrogen peroxide into alkyl hydroperoxides, alcohols, and ketones [6-9, 11, 16, 17], as well as the hydrocarboxylation of gaseous and liquid C ( = 2 - 9) alkanes, by carbon monoxide, water, and potassium peroxodisulfate into the corresponding carboxylic acids [12-15, 18-22]. 

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