Germyllithiums reactions with

When steric hindrance makes nucleophilic substitution difficult, germyllithiums reacted with acyl chlorides to give a competitive SET reaction (equation 184 and Scheme 38)15. 

The reaction of these electrochemically generated anions with phenylacetylene (i) was compared with the same reaction with the corresponding germyllithiums (ii). The stereochemistry of the resulting vinyl intermediates was different. Reaction (ii) produced a mixture of Z (33%) and E (57%) 2-organogermylstyrene, while reaction (i) led to Z (75%) and E (25%) 2-organogermylstyrene. These differences were interpreted in terms of the dependence of the activation energy for the isomerization of the intermediate on the nature of the counterion and its state of solvation . ... 

Since the original preparation of optically active germyllithium by Brook and Peddle (31), these reagents have been found to undergo various stereospecific reactions. Carbonation and reaction with carbonyl compounds (eq. [12]) lead to retention of configuration at germanium (31). 

We assume that all these reactions take place with retention of configuration at germanium because germyllithium always reacts with this stereochemistry. ... 

Anions prepared by direct reaction of germyllithium with metal carbonyls or by hydrogen abstraction are obviously identical and reveal the same reactivity. 

Most of the reactions of silicon or germanium organic compounds proceed photochemically via a radical mechanism or via a cycloaddition mechanism (Chapters 4 and 6). There are few examples of nucleophilic addition of RSi or RGe to Cgo [118,119]. Reaction of silyUithium derivatives RjSili or germyllithium derivatives RjGeLi with different alkyl- and aryl-substituents R yields mainly the 1,2-adduct 28 or the 1,16-adduct 29 1,4-addition and dimerization of two fullerene-units was also found as a minor pathway. One example is given in Scheme 3.15. 

The reaction of germyllithiums with chloromethyl methyl ether gave the germylmethyl methyl ether in good yield (equation 91)9,136. 

The X-ray analysis of diphenylbis[tris(trimethylsilyl)germyl]plumbane, obtained from the reaction of diphenyldichlorolead with the appropriate germyllithium (equation 131), showed a staggering of methyl groups around the lead center154. 

The reaction of germyllithiums with C6o gave different 1,2-monoadducts (equation 175)185, the structures of which were resolved by X-ray analysis. 

A route to germyllithiums is reaction of xs RjGeLi with a germylene, such as GeXj in 1,2-dimethoxyethane (DME), e.g. ... 

The synthesis of digermanes was similarly achieved using stereospecific reactions of germyllithium (33). The optically active anion 17 reacted with a menthoxy-germane of the same, 18 (or opposite, 19) relative configuration, leading to the meso, 20 (or optically active, 21) digermane (Scheme 1). 

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