[reaction: see text] LiBr catalyzes efficiently the dihydroxylation of alkenes to afford syn and anti diols with excellent diastereoselectivity depending upon the use of NaIO(4) (30 mol %) or PhI(OAc)(2) (1 equiv), respectively, as the oxidants. The oxidation of non-benzylic halides has been achieved for the first time to afford the corresponding diols in excellent yields.

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A new transition-metal-free, sodium metaperiodate (NaIO4)-mediated direct oxidation of methylarenes and benzylic bromides to the corresponding aromatic carboxylic acids is described. Under the same reaction conditions, benzylic alcohols are selectively oxidized to afford the corresponding aldehydes in good yields without undergoing overoxidation. Unprecedentedly, oxidation of benzyl bromide, toluene, or benzyl alcohol with NaIO4 underwent nuclear bromination followed by oxidation to give 4-bromobenzoic acid in 60-79% yields.

A new method for the oxidation of aromatic olefins and alkynes has been developed using inexpensive iron(III) chloride hexahydrate (FeCl(3)center dot 6H(2)O, 5 mol%) catalyst in combination with commercially available aqueous 70% tert-butyl hydroperoxide (TBHP) as oxidant. The present system works well for aromatic alkenes and alkynes with both electron-donating and electron-withdrawing substituents being tolerated. The protocol is free from chromatographic purification and the carboxylic acids are obtained in high yields by simple filtration

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