Organomagnesium halides reagents

Organomagnesium halide reagents RMgX (RX = CjH,Br, i-PrBr, n-BuBr, PhBr) react in toluene-ether with (t7 -Cp)2MoH2 to form compounds II, in which each molecule contains four Mo—Mg bonds " . When II is dissolved in THF a red solution is formed, which after concentration yields orange crystals of III. Compound III is monomeric with a Mo—Mg bond of length 273.2 pm, consistent for Mo as a one-electron donor. 

Among organomagnesium halide reagents, only Mg(I)Me and Mg(Br)CH2-Ph react with (>/ -Cp)2TiCl2 to give dialkylated products the route usually leads to... 

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 ... 

The reaction of organolithiums or organomagnesium halide reagents with silver halides produces organosilvers, but these are less stable than those containing Cu and Au and readily decompose to form homo-coupled products via alkyl radicals ... 

Hydrolysis of magnesium amides from organomagnesium-halide reagent addition to imsaturated nitrogen compounds proceeds similarly" ... 

Aluminum alkyls, although inconvenient to handle because of their spontaneous inflammability, are powerful reducing agents and are applied to the synthesis of transition-metal hydrides . They, and the organomagnesium halide reagents to be discussed in 1.10.8.4, function by initial alkylation of the transition metal (e.g., for EtjAl) ... 

As a secondary organomagnesium halide reagent, cyclohexylmagnesium bromide may also be useful for the synthesis of metal hydrides ... 

For those reactions covered by Eqs. (c) and (e), the order of addition of the organolithium or organomagnesium-halide reagents and the starting Cu salts may affect the nature and purity of the organocopper products (cf. ref. 4 for a discussion and examples). 

In the syntheses of trialkylaluminums, primary, secondary or tertiary alkyl groups are transferred from Li or Mg to AI e.g., t-BujAl-OEtj is isolated as a crystalline solid in > 70 % yield (AICI3 in Et20 is added to the organomagnesium-halide reagent) ... 

Organomagnesium halide reagents react with GaXj to give, depending on the conditions, 1 1 solvates or solvent-free RjGa ... 

The organomagnesium-halide reagents are sensitive to air and moisture and are, therefore, used directly in solution for further transformations. However, they may be isolated as white, frequently self-igniting solids that are stable to ca. 100°-150°C. Their structures in the solid state involve coordination numbers for Mg varying from three to six, but the majority of cases show Mg to be tetracoordinated, with one organic group. 

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