Germyllithium reagents

FIGURE 2. Proposed pathway for alkylation of germyllithium reagents with alkyl iodides... 

In contrast, silyl- or germyllithium reagents attack one of the trimethylsilyl groups attached to the central silicon atom rather than the carbonyl group of the acylsilanes 179120-122 Subsequent elimination of disilane or germylsilane, respectively, results in the formation of lithium silenolate anions 180-183 (equation 45), which were characterized by NMR spectroscopy (see Section I.C.2)120-122 and by trapping experiments120-123. 

The analogous asymmetric germyl anion appears to be more optically stable. Solutions of optically active germyllithium reagent are easily prepared by treatment of a chiral hydrogermane with butyllithium96-98 (equation 29). 

The germyllithium reagents have been found to undergo a variety of stereospecific reactions99"102. 

In addition to these general methods, Nicholson and Allred (6) have found that the addition of germyllithium reagents to aromatic acid chlorides at low temperature leads to excellent yields of acylgermanes. However, the... 

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). 

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