Magnesium, reaction of with alkyl and

McGwire, Mark, 1041 Macrolide antibiotics, 758 Magnesium, reaction of with alkyl and aryl halides, 550-551, 571 Magnetic field... 

Alkyl and aryl iodides usually react with magnesium more rapidly than the corresponding bromides, and the bromides very much more rapidly than the chlorides. Aryl (as distinct from alkyl) chlorides have usually only a slow reaction with magnesium and are therefore very rarely used. With alkyl and aryl iodides in particular, however, a side reaction often occurs with the formation of a hydrocarbon and magnesium iodide ... 

Reaction of an alkyl (usually trimethyl) of Group-IIIb element (Al, Ga, In) with a hydride of a Group-Vb element (P, As, Sb) at 600-800°C and 1 atm. [4i][42] p. doping obtained from addition of diethyl zinc or bis(cyclopentadienyl) magnesium. 

Reaction of Various Aldimine and Ketimine Magnesium Bromide Salts with Alkylating Agents in Tetrahydrofuran... 

The reaction with alkyl- and aryllithium reagents has also been carried out without preliminary formation of RLi a mixture of RX and the carbonyl compound was added to a suspension of lithium pieces in THF.364 Yields were generally satisfactory. The magnesium analog of this process is called the Barbier reaction,365 Lithium dimethylcopper Me2CuLi... 

Like magnesium, lithium reacts with alkyl halides, vinyl halides, and aryl halides to form organometallic compounds. Ether is not necessary for this reaction. Organolithium reagents are made and used in a wide variety of solvents, including alkanes. 

Many other kinds of orgonometallic compounds can be prepared in a manner similar to that of Grignard reagents. For example, nlkyllithium reagents, RU. can he prepared by the reaction of an alkyl halide with lithium metal. Alkyllithiuma are both nucleophiles and bases, and their chemistry is similar in many respects to that of the alkyl magnesium halides. 

In 1912 Victor Grignard received the Nobel prize in chemistry for his work on the reaction that bears his name, a carbon-carbon bond-forming reaction by which almost any alcohol may be formed from appropriate alkyl halides and carbonyl compounds. The Grignard reagent is easily formed by reaction of an alkyl halide, in particular a bromide, with magnesium metal in anhydrous ether. Although the reaction can be written and thought of as simply... 

There are very few studies of the Barbier reaction mechanism with magnesium as the metallic source. However, with the discovery that the reaction will often proceed to a greater extent with other metals such as lithium, some good mechanistic studies have been conducted. The focus of most of these studies has been the reaction of an alkyl or aryl halide with a ketone. The conclusions drawn from these studies are considered to be valid for magnesium as well, and they will be referenced in this section. 

Reactions of Activated Magnesium with Alkyl and Aryl Halides... 

In this section, the reactions of gew-dibromocyclopropanes and dibromomethylsilanes with trialkylmagnesate reagents are described. Preparation of a chiral secondary Grignard reagent by alkylation of the chiral magnesium carbenoid species is also discussed. 

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