Dimethylsulfonium dicarbonylmethylides

Oxidation of p-hydroxy ketones. Reaction of the Corey-Kim reagent with these substrates can result in dimethylsulfonium dicarbonylmethylides in 80-98% yield. These S-ylides are desulfurized to p-diketones by zinc in acetic acid, p-... 

The Corey-Kim conditions have also been applied to 3-hydroxycarbonyl compounds to afford 1,3-dicarbonyls and this variation is curious in that in some cases stable dimethylsulfonium dicarbonylmethylides are isolated which have to be further treated with zinc-acetic acid to afford the desired dicarbonyl product. In 1988, Yamauchi showed that the outcome of the addition of 3-hydroxycarbonyls to the Corey-Kim reagent varied depending upon the C-2 substitution pattern.10 As illustrated by the examples below, if the C-2 position is unsubstituted such as in 38, the dimethylsulfonium dicarbonylmethylide 39 was isolated whereas the desired oxidation product 42 was produced if there was at least one substituent (Rj or R4) present at C-2. Other cases of non-C-2-substituted 3-hydroxycarbonyls furnishing stable dimethylsulfonium methylides and their conversion to die desired diketones have been reported. 

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See also in sourсe #XX -- [ ]

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