Preparation of magnesium ate complexes

The reaction represented by equation (3) is fairly general, and several complexes with the stoichiometry MMgR3 have been isolated and characterized [D] an example is LiMgPh3, as a dimeric TMEDA complex [21]. An alternative method for preparing such complexes in solution is the reaction of an alkali metal with a dialkylmagnesium [22]  

However, a range of other stoichiometries is possible [D], and Na2MgPh4, for example, has been characterized as its PMDETA complex [23]. Remarkably, some magnesium ate complexes, e.g. NaMgBu Bu, are soluble in hydrocarbons [24]. 

Brandsma and FI. Verkruijjse, Preparative Polar Organometallic Chemistry, Vol. 1, p. 158. Springer-Verlag, Berlin, 1987. 

Covered in this section are processes which result in the substitution of the ligand X in an organomagnesium compound, RMgX  

For application in synthesis, the most important of these are those where X = halogen and Y = alkyl the transformation of Grignard reagents into dialkylmagnesium compounds. Other transformations of this type are valuable for preparing alkylmagnesium hydrides (Y = H), alkoxides (Y = OR ), carboxylates (Y = OCOR ), amides (Y = NR 2, thiolates (Y = SR ), etc., but since most of these products are not extensively employed in synthesis these transformations are summarized only briefly. 

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