Organomagnesium ate complexes

The chemistry of organomagnesium ate complexes TABLE 2. Reactions of 2-cyclohexen-l-one with ethylmetals... 

Oshima, K. Selective halogen—magnesium exchange reaction via organomagnesium ate 483 complexes./. Org. Chem. 2001, 66, 4333—4339. 

Organomagnesium compounds sometimes behave as single-electron donors. Such behaviour is most likely to be observed in highly polar, cation-solvating media and/or when steric hindrance inhibits alternative pathways. Ate complexes of magnesium can also act as single electron donors (see p. 97). It should be noted that the presence of traces of transition metals may lead to electron transfer processes [2]. 

Active polymerization catalysts have been derived from organomagnesium compounds, for example by reaction with titanium (tv) chloride [7] the polymerization of various vinyl monomers has been initiated by organomagnesium compounds [8] and recently polymerization initiated by magnesium ate complexes has been described [9, 10]. 

The reaction of organolithiums or organomagnesium halide reagents with gold halides proceeds similarly to the copper halides in a 1 1 ratio. Their phosphine complexes can be isolated and characterized. In a 2 1 ratio, the transmetallation reaction is followed by ate complexation to form organoaurate complexes ... 

Organomagnesium compounds show less tendency than organolithium compounds to form the cationic part of ate complexes (but see, for example, the cobalt example in Table 16.1). Indeed, even with aluminum the complexes are probably better regarded as mixed aggregates, for example Mg2Al2(CH,) [70] and the volatile complexes [(n-C4H,)2MgAl(OR)3]2 [71], It should also be noted that magnesium can also participate in the anionic part of ate complexes (see Section 3.3.3). 

Oxidative coupling. Organolithium and organomagnesium compounds react with the complex in THF or dimethoxyethane at —78° to give copper(l) ate complexes, which in the presence of atmospheric oxygen undergo coupling.2 The reaction of it-butyllithium is typical ... 

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