Digermanes synthesis

Biotransformation as a Preparative Method for the Synthesis of Optically Active Silanes, Germanes, and Digermanes Studies on the (l )-Selective Microbial Reduction of MePh(Me3C)ElC(0)Me (El = Si, Ge), MePh(Me3Ge)GeC(0)Me, and MePh(Me3Si)GeC(0)Me Using Resting Cells of Saccharomyces cerevisiae (DHW S-3)... 

Synthesis of Optically Active Silanes, Germanes, and Digermanes 239... 

In conclusion, enantioselective microbial reductions of silicon and germanium compounds containing an El-C(0)Me (El = Si, Ge) moiety El-CH(OH)Me] proved to be an efficient preparative method for the synthesis of optically active silanes, germanes, and digermanes. Furthermore, the commercially available yeast Saccharomyces cerevisiae (DHW S-3) is considered to be an efficient biocatalyst for this particular type of bioconversion. 

Convenient and inexpensive Me3SiCl can be used as solvent for the relative stable silylmercury. Displacement occurs smoothly and the thermally labile germylmercury species may be kept at low temperatures or prepared in situ. Their use in Ge-metal synthesis is discussed in S.8.4.S the other application is in the synthesis of digermanes or silylgermanes by elimination of mercury... 

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). 

Scheme 1. Stereospecific synthesis of digermanes from a chiral germyl anion.

Chlorodigermane. If it is essential to manipulate a digermanyl halide, it is preferable to use the more stable chloride. In addition to the synthesis from the iodide, the chloride may be made from the reaction of digermane with heated AgCl4 or with a deficit of SnCl4 at room temperature according to the equation 11... 

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