Grignard reagents, formation

Barbier reported (1) in 1899 that a mixture of methyl iodide, a methyl ketone, and magnesium metal in diethyl ether produced a tertiary alcohol. Detailed studies by his student Victor Grignard are documented in his now classical doctoral thesis, presented in 1901. Grignard estabUshed (2) that the reaction observed by Barbier could be separated into three distinct steps Grignard reagent formation, Grignard reaction, and hydrolysis. 

The mechanism of Grignard reagent formation involves free radicals," and... 

Grignard reagent formation amidation of a Lepetit Research Nebuloni and... 

Formation of Grignard reagent formation of Ciba-Geigy Brogli etal. (1981)... 

After quenching with DzO or Bu OD, analysis of the products from the Grignard reagents formed from PhCHXMe (X = Cl, Br, I) in the optically active solvent -(R)-2-methoxypentane leads to the conclusion that Grignard reagent formation occurs on the Mg surface within a solvent cage by a one-electron transfer mechanism.1... 

Eor factors controlling Grignard reagent formation, see W. E. Lindsell, in Comprehensive Organometallic Chemistry I (Eds. G. Wilkinson, E. G. S. Stone and G. E. Ebel), Vol. 1, Chap. 3, Pergamon Press, Oxford, 1982, pp. 155-252 and references therein. 

Alkanes can also be prepared from alkyl halides by reduction, directly with Zn and acetic acid (AcOH) (see Section 5.7.14) or via the Grignard reagent formation followed by hydrolytic work-up (see Section 5.7.15). The coupling reaction of alkyl halides with Gilman reagent (R 2CuLi, lithium organocuprates) also produces alkanes (see Section 5.5.2). 

Reactions of Arvl Halides 3.10.2.1 Grignard Reagent Formation... 

C. Walling, The Nature of Radicals Involved in Grignard Reagent Formation, Acc. Chem. Res. 1991, 24, 255. 

C. Humdouchi, H. M. Walborsky, Mechanism of Grignard Reagent Formation, in Handbook of Grignard Reagents (G. S. Silverman, P. E. Rakita, Eds.), Marcel Dekker Inc., New York, 1996, 145—218. 

J. F. Garst, F. Unvary, Mechanisms of Grignard Reagent Formation, in Grignard Reagents—New Developments, Ed. by H. G. Richey, Jr., John Wiley Sons, Chichester, U. K., 2000, 185—275... 

Reactivity in Grignard reagent formation varies in the sequence I > Br > Cl > F. Fluorides are particularly unreactive, but Grignard preparation has been reported with metal vapor and matrix-isolation techniques. Mg anthracene, and most efficiently, with Rieke magnesium. Side reactions with iodides, and to a lesser extent bromides, may lower the yield of the reagent. 

Solvents for (irignard reactions. J. T. Baker supplies dry, peroxide-free ether and THF containing an activator for Grignard-reagent formation. 

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