Monomeric Magnesium Amides

The low solubility of magnesium amides is the result of their state of aggregation. On the contrary, TMPMgQ-LiCl has a monomeric structure and can be handled as a 1.2 M solution in THF [29]. The improved kinetic basicity of this reagent allows the selective magnesiation of oligofunctional compounds (Scheme 5.4) [30]. As... 

Reaction mechanism Detailed mechanistic studies have been conducted on this reaction. While the stoichiometric protonolysis reaction of [ (ArNCMe)2CH Mg" Bu]2 with benzylamine, 2-methoxyethylamine, and pyrrolidine to yield the corresponding dimeric magnesium amides and methane proceeds rapidly and non-reversibly at room temperature [88], the reaction of [ (ArNCMe)2CH Ca N (SiMe3)2 (THF)] with benzylamine forms a quantifiable equilibrium between monomeric bis(trimethylsilyl)amide and dimeric benzylamide reaction products. A van t Hoff analysis of this equilbrium mixture allowed derivation of AG°(298 K) as —2.7 kcal mol consistent with facile precatalyst activation via protonolysis with a primary amine [76, 87]. 

Chisholm, M. H. Gallucci, J. Phomphrai, K. Coordination chemistry and reactivity of monomeric alkoxides and amides of magnesium and zinc supported by the diiminato ligand CH(CMeNC6H3-2,6- Pr2)2- A comparative study. Inorg. Chem. 2002,41, 2785-2794. 

---