Heterosubstituted methyllithium compounds

Lithium-tellurium exchange can be put to further use, allowing the generation of a variety of heteroatom-substituted methyllithiums suitable for trapping with electrophiles.  

The reaction can also be performed satisfactorily in different solvents such as ether, 

Heteroatom-substituted methyllithiums (typical procedure) To a solution of Me0(CH2)20CH2TeBu-n (0.274 g, 1.0 mmol) in THF (5 mL) is added n-BuLi (1.6 M in 

Bis(butyl tellurium)methyl sulphide, prepared from bis(bromomethyl)sulphide and n-BuTeLi by treatment with 2 equiv of n-BuLi, gives rise to the corresponding bis(lithium methylsulphide), which can be isolated under vacuum as a colourless powder and stored at -20°C for 6 months. It decomposes under argon at 60°C and ignites explosively upon contact with traces of air. 

Reaction with BujSnCl and Me2PSiCl leads to the corresponding bis-stannylated and bis-silylated derivatives.  

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Tris-heterosubstituted organolithium compounds are considered as carboxyl anions and related synthons. Tris(methylsulfanyl)- and tris(phenylsulfanyl)methyllithium, 496 and 497, and other acyclic tris(alkylsulfanyl)methyllithiums 498-500 and cyclic ones 501 and 502 have been described as sulfur-containing LiCXYZ compounds12,684 687. 

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