Sodium amide, carbanion formation with

Among the ethers of prolinol, (5)-2-methoxymethylpyrrolidinc [SMP, (S)-10] has found most applications. It is readily prepared from prolinol by the normal sodium hydride/iodo-methane technique9,13 (sec also Section 2.3. for O-alkylations of other amino alcohols) and is also commercially available. An improved synthesis from proline avoids the isolation of intermediates and gives the product (which is highly soluble in water) by continuous extraction14. SMP has been used as the lithium salt in deprotonation and elimination reactions (Section C.) and as an auxiliary for the formation of chiral amides with carboxylic acids, which in turn can undergo carbanionic reactions (Sections D.l.3.1.4., D.l. 1.1.2.. D.l. 1.1.3.1., in the latter experimental procedures for the formation of amides can be found). Other important derivatives are the enamines of SMP which are frequently used for further alkylation reactions via enolates (Sections D.l.1.2.2.. where experimental procedures for the formation of enamines are... 

Sulphonyl ylides usually are obtained by proton removal from a sulphone. Jarvis and Saukaitis" have found that the reaction of an a-bromo- or o-chloro-sulphone with triphenylphosphine resulted in abstraction of the halc en and formation of the sulphonyl ylide as an intermediate, which was trapped by protons from the water present. Benzyl phenyl sulphone was converted into the aa-dilithio-carbanion by treatment with n-butyl-lithium in THF-heptane," and Bosworth and M nus " have reported that a bicyclic phenylsulphone, upon treatment with n-butyl-lithium and then D2O, was converted into the ao-dideuteriosulphone, and that it was not possible to obtain the mono-deuteriosulphone by that method. Kaiser et al. have found that using sodium, lithium, or potassium amide with dimethyl sulphone or with dibenzyl sulphone resulted in formation of the aa -dicar-banion, as detected by deuteriation or by reaction with benzophenone. Amel and Marek determined the pK. s of a series of phenylphenacyl sulphones and concluded that the sulphone group provided less stabilization for the phenacylide than did a sulphonium group. The p value for substituents on the phenacyl portion was similar to that obtained for sulphonium, phosphonium, arsonium, and pyridinium phenacylides. 

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