Tosylates Komblum oxidation

The Komblum oxidation was the first reported oxidation reaction using DMSO. a-Bromo ketones such as 23 were converted to the corresponding glycoxals in good yield.1 Less reactive halides, such as most benzylic halides and aliphatic halides, can be oxidised by conversion to the tosylate derivative with silver tosylate and then oxidising in situ with a sodium bicarbonate-DMSO mixture.17,18... 

Komblum et al. had asserted that it was necessary to convert primary iodides to tosylates for the oxidation to proceed. However, Johnson and Pelter have claimed that primary iodides can be oxidized directly. They observed that ketonic substrates failed, undergoing aldol condensation under the reaction conditions, but that hydroxy-containing halides reacted normally. For substrates insoluble in DMSO such as 1-bromododecane, they found that DME worked well as a cosolvent. The most interesting example... 

One way to increase the nucleofiigacity of halides is to introduce silver ion. Komblum reported that primary unactivated chlorides, bromides and iodides could be oxidized by prior conversion to the tosyl-ate with silver tosylate, followed by reaction in DMSO (Scheme 4). ... 

Oxidations using dimethyl sulfoxide activated by various reagents began with discoveries by Komblum and co-workers that primary tosylates and certain a-bromo ketones could be converted into aldehydes and glycoxals, respectively, by treatment with dimethyl sulfoxide as the oxidising agent. This was followed by the discovery several years later by Pfitzner and Moffatt that alcohols could be oxidised to carbonyl compounds with dimethyl sulfoxide, dicyclohexylcarbodiimide (DCC) and phosphoric acid at room temperature.2 Eventually the method developed by Swern and co-workers, involving activation of dimethyl sulfoxide with oxalyl chloride, came to be the most synthetically useful and widely applied of these mild oxidation procedures.3-6... 

Komblum N, Frazier HW (1966) A new and convenient synthesis of glyoxals, glyoxalate esters, and a-diketones. J Am Chem Soc 88(4) 865-866. doi 10.1021/ja00956a063 Komblum N, JonesWJ, Anderson GJ (1959) A new and selective method of oxidation. The conversion of alkyl halides and alkyl tosylates to aldehydes. J Am Chem Soc 81(15) 4113-4114. doi 10.1021/ja01524a080... 

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