Lithiumorganic compounds

The mechanism of this unusual dimerization is not known. All the lithiumorganic compounds have been identified by the reaction with dimethyl sulfate as well as by deuterolysis with deuterium oxide. 

Waak 13-15) was the first to attempt anionic initiation by means of an unsaturated lithiumorganic compound, namely vinyllithium. This reagent can be obtained by an exchange reaction between tetravinylzinc and butyllithium ... 

Due to our engagement in carbanion rearrangements we were especially interested in the homoallylic system 4,4-dilithio-l-butene 33. In the case of homoallyllithium 29 ring-chain equilibrium strongly favors the open-chain lithiumorganic compound and the introduction of four methyl groups into the a- and -positions is necessary... 

Transmetalation reactions with several other elements of the periodic table can also be used for the synthesis of lithiumorganic compounds but polylithiated... 

In contrast, isocentric polylithiated hydrocarbons often show reactivities quite atypical for normal lithiumorganic compounds. Already in 1971 Krohmer and Gou-beau reported that dilithiomethane 3 reacts with chlorotrimethylsilane only under forced conditions — 48 hours at 150 °C in a sealed tube — which is rather unusual for an alkyllithium compound. We found that -the reaction can be performed much more conveniently by refluxing CHjLij in McjSiCI in the absence of a solvent, but anyhow it needs four days to be complete... 

However, the efficiency of this compound as an anionic polymerization initiator is rather poor, as compared with that of standard lithiumorganic initiators. 

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