Dodecyl methyl sulfoxide

Similarly, when dodecyl methyl sulfoxide (C12H25SOCH3) is used in the Swern oxidation, the odourless Dod-S-Me by-product instead of foul-smelling DMS is formed. 

This Dod-S-Me recovered from the reaction can be reoxidized to dodecyl methyl sulfoxide by sodium periodate. 

An unavoidable by-product of the Swem reaction is the volatile dimethylsulphide which, on account of its unpleasant smell, is a reagent regulated by offensive odour control laws. This makes large scale chemistry problematic, especially in industry. To overcome this, several methods exist to perform the Swem oxidation under odourless conditions. For example, Node et al. outline a protocol for the Swem oxidation which uses dodecyl methyl sulfoxide in place of methyl sulfoxide,12 while Crich and co-workers have developed a fluorous Swem oxidation reaction that uses tridecafluorooctylmethyl sulfoxide 17,l3a,b This reagent can be recovered via a continuous fluorous extraction procedure and recycled by reoxidation with hydrogen peroxide. Additionally, the fluorous DMSO is crystalline, odourless and soluble in CH2CI2 to —45 °C. 

One drawback of these reactions is the formation of volatile, odorous dimethyl sulfide. Various solutions to this problem have been reported, such as the use of dodecyl methyl sulfoxide (Ci2H25SOMe) with oxalyl chloride followed by triethy-lamine. The by-product dodecyl methyl sulfide is non-volatile and yields are only slightly reduced in comparison with the use of dimethyl sulfoxide. 

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