Use of Tellurium(IV) and Tellurium(VI) as Oxidants in Organic Synthesis

Article abstract of DOI:10.1021/jo00147a031

The oxidizing properties of TeO2, Te(OH)6, and TeO3 in acetic acid solution containing LiBr have been explored.It was found that certain aromatic compounds were acetoxymethylated by the action of TeO2 or, when especially activated, converted into diarylmethane derivatives.Te(OH)6 and TeO3, in contrast, mainly effected side-chain acetoxylation, as was also the case with SeO2.In the acetoxymethylation reaction TeO2 apparently slowly oxidized the solvent, HOAc, to a reactive species of some kind, e.g., acetoxycarbene, which attacked the aromatic compound.In the side-chain acetoxylations, Te(VI) oxidized bromide ions to Br2, which caused benzylic bromination.The solvolysis of benzylic bromides to acetates was significantly enhanced by the presence of Te(IV) species.Both TeO2 and TeO3 effected more conventional oxidations like the transformation of deoxybenzil to benzil.Benzoin acetate is a probable intermediate in this oxidation.