Sulfoxide, methyl thiomethyl

The seleno derivative 1374, which can be readily prepared by reduction of di-phenyldiselenide with sodium borohydride then alkylation with chloromethyltri-methylsilane, is alkylated to 1375 to give, on oxidative hydrolysis, aldehydes 1376 in high yields, PhSe02H-H20 1377 [104], and 7 (Scheme 8.44). Alkylation of the commercially available methyl thiomethyl sulfoxide 1378 leads to mono- or dialkyl... 

Monoalkylation of the carbanion generated from methyl thiomethyl sulfoxide and 1,3-dithiane I-oxide - has been reported (Scheme 74, entry b) but reexamination of both reactions - proved unsatisfactory under conditions similar to those previously described or slightly modified. Neither the stepwise- nor the one-pot dialkylation was successful at 20 C, but the latter reaction was apparently achieved by Schill- by performing it at 50 °C with a slight excess (2.2 equiv.) of n-alkyl bromides in... 

As expected ( )-l,4-dichlorobut-2-ene reacts differently from its (2Z)-isomer with methyl methyl-thiomethyl sulfoxide, and produces a vinylcyclopropane instead of the cyclopentene derivative (Scheme 83, entry b, compare to entry a). 

Aromatische Aldehyde kondensieren mit Methyl-thiomethyl-sulfoxid zu Keten-dithioacetal-monoxiden, die hydrolytisch in substituierte Aryl-essigsauren ubergefuhrt werden konnen419. 

Zur Kondensation von Carbonyl-Verbindungen mit Isonitrilen bzw. Methyl-thiomethyl-sulfoxid s. S. 361. 

Methyl Methylthiomethyl Sulfone. Methyl methyl-thiomethyl sulfone is the 5-methyl analog of MT-sulfone and it is conveniently synthesized by oxidation of methyl methylthiomethyl sulfoxide (FAMSO) with potassium permanganate or H202-Na0H. It is useful for synthetic methods similar to those using MT-sulfone synthesis of carboxylic esters, ketones, and a-aLkoxy- -arylacetates. In the reaction of this reagent with allylic bromides, a-methylthio- /,5-unsaturated sulfones are obtained by stirring the bromide with potassium carbonate and potassium iodide in hexamethylphosphoric triamide (eq 14), which does not occur with MT-sulfone. 

In comparison to some of the other activation methods however, the dimethyl sulfoxide-acetic anhydride procedure has certain disadvantages. The method often requires the use of long reaction times (1 24 h), which can result in many side reactions, especially with sensitive substrates. Notable in this respect is that it is not uncommon for this procedure to result in the formation of substantial yields of the thiomethyl ethers obtained from the Pummerer rearrangement product as described above. In fact upon attempted oxidation of cholesterol with this system, the major product obtained was the corresponding (methylthio)methyl ether. Acetates may also be formed if the alcohol is unhindered. For example the sugar derivative (9) reacts under these conditions to form an enol acetate (derived from the requir carbonyl compound) in 40% yield contaminated with 30% of the acetate (10 equation S). ... 

An alternate route to a -thiomethyl methyl sulfoxides involves substitution of an a-chloromethyl sulfoxide with sodium thiomethoxide. ... 

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