Organomagnesium amide

Organomagnesium amides and related compounds with group 15-bonded ligands 106... 

The structures in the solid state of three of the initially formed organomagnesium amides, 222, 223 and 224, were determined by X-ray crystallography. All three compounds are discrete monomers and have comparable structures of which that of 222 is shown (Figure 93). In 222 the ethyl group is a-bonded to magnesium and interacts with the three nitrogen atoms of the A-alkylated 2,6-bis(imino)pyridine in a pincer-type ... 

FIGURE 100. Schematic representation of the stmctures of organomagnesium amides 255-263 derived from secondary amines... 

This chapter is devoted to the chemistry of organomagnesium-group 15- and group 16-bonded complexes, with emphasis on their synthesis, structural characterization and utility. In particular, organomagnesium amides will be the central focus of the first section, as... 

II. ORGANOMAGNESIUM-GROUP 15-BONDED COMPLEXES A. Organomagnesium Amides... 

TABLE 1. Stmcturally characterized organomagnesium amides synthesized from the reaction of amines or metal amides with diorganomagnesium precursors... 

TABLE 3. Structurally characterized organomagnesium amides synthesized by miscellaneous methods... 

Many monomeric organomagnesium amide solvates may be transformed on heating under vacuum. In some instances this leads to simple desolvation of the complexes and in turn gives rise to dimerization or even further aggregation Another outcome... 

A useful application of organomagnesium amides is in the enantioselective conjugate addition to enamidomalonate to prepare /3-amino acid derivatives (Scheme 16). The alkylmagnesium amide complexes provided both high yields and high selectivity in the organic transformation. 

Chiral organomagnesium amides form an efficient method to realize enantioselective conjugate addition. Sibi and Asano have reported the Michael addition of cr-bound magnesium reagents derived from bisoxazolines to enamidomalonates (equation 41). The enantioselectivity of the addition is discussed in Section El. This method allows the preparation of chiral -amino acid derivatives. ... 

---