Sulfoxide, methyl methylthiomethyl alkylation

Carbanions formed from methyl methylthiomethyl sulfoxide 94 and ethyl ethylthio-methyl sulfoxide 95 were shown to be alkylated in excellent yields126,127. Treatment of 94 with rc-BuLi or KH and subsequent reaction with 1, n-dihalo- or bis(tosyloxy)alkane gave 3-, 4-, 5- and 6-membered 1-methylsulfmyl-l-methylthiocycloalkanes128"130. Upon hydrolyses of these products, the corresponding aldehydes and ketones are obtained. 

For a recent synthesis of a-oxoacid amides from nitriles using methyl methylthiomethyl sulfoxide see ref. (478). Further interconversions between a-acylamino-a-hydroxy acid derivatives and the corresponding a-acylamino-a-aryl(alkyl)thio-, a-arylamino- and a-alkoxy compounds were reported (479, 480, 511). 

The methylthiomethyl (MTM) group is a related alcohol-protecting group. There are several methods for introducing the MTM group. Alkylation of an alcoholate by methylthiomethyl chloride is efficient if catalyzed by iodide ion. Alcohols are also converted to MTM ethers by reaction with dimethyl sulfoxide in the presence of acetic acid and acetic anhydride or with benzoyl peroxide and dimethyl sulfide. The latter two methods involve the generation of the methyl-thiomethylium ion by ionization of an acyloxysulfonium ion. 

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