Germanium amines, tertiary

Although there are no informations available concerning the structure of the dilithiated 1,3-diamines in solid phase or in solution, subsequent reactions of la,b with di- and trichlorosilanes support the existence of these dianions. la,b are important building blocks in organoelement synthesis, not only restricted to the field of silicon chemistry. Remarkable results have been achieved in reactions with N- or C-substituted dichlorophosphanes. An extension to germanium and tin is possible, but side reactions or lower yields are often observed. Nevertheless, the facile double metalation of TMMDA and CMMDA is unique for tertiary amines (e g., the phosphorus homologue (CH3)2PCH2P(CH3)2 is only metalated at the methylene carbon atom [8]). 

Diazo(trialkylsilyl)acetates 1 can be prepared conveniently from an alkyl diazoacetate and a trialkylsilyltriflate in the presence of a tertiary amine (path A). Furthermore, metalation of ethyl diazoacetate with butyllithium at — 110 °C, followed by addition of chlorotrimethylsilane provides ethyl diazo(trimethylsilyl)acetate. Ethyl diazo(trimethylsilyl)acetate and the corresponding trimethylgermyl- and trimethylstannyl- substituted diazoacetate have been prepared from mercury bis(ethyl diazoacetate) and bis(trimethylsilyl-, germyl- or stannyl)sulfide (path B). Ethyl diazo(trimethylgermyl)- and ethyl diazo(trimethylstannyl)acetate were obtained from ethyl diazoacetate and diethylaminotrimethyltin or -germanium (path C). Similarly, the ethyl (trimethylplumbyl)diazoacetate was obtained from bis(trimethylsilyl)aminotrimethyl-lead. 2... 

Reactions between germanium tetrachloride, alkyltrichlorogermane, or dialkyldichlorogermane and secondary amines in petroleum ether yield compounds of the type Ge(NR2)4, RGe(NR2)3, and R2Ge(NR2)2i respectively 4,26). With tertiary amines the germanium halides either do not react or form adducts (cf. Table I). 

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