Tetramethylsilane in synthesis: Selective mono- and polymethylations of germanium tetrachloride

Article abstract of DOI:10.1021/om00125a024

In the presence of catalytic amounts of aluminum bromide (or chloride), selective mono-, di-, tri-, or tetramethylation of germanium tetrachloride was effected in high yield with tetramethylsilane (Me₄Si) as the methylating reagent. According to the Me₄Si/GeCl₄ ratio, MeGeCl₃, Me₂GeCl₂, Me₃GeCl, and Me₄Ge were prepared in 66, 86, 100, and 91% maximum yields, respectively. In these reactions, Me₄Si was converted into Me₃SiCl and subsequently Me₂SiCl₂. A mechanism for methylation is proposed, involving the initial formation of Me₄Ge (observed regardless of the proportions of starting reagents) followed by disproportionation reactions, with methylchlorosilanes or -germanes present when the initial molecular ratio Me₄Si/GeCl₄ was lower than 4/1.