Grignard Reaction

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Grignard reaction

[grin′yär rē‚ak·shən]
(organic chemistry)
A reaction between an alkyl or aryl halide and magnesium metal in a suitable solvent, usually absolute ether, to form an organometallic halide.

Grignard Reaction


a general method of synthesizing organic substances using mixed organomagnesium compounds (Grignard reagents) of the type RMgX, where R is an aliphatic or aromatic radical and X is a halogen (usually Br or I, more rarely C1). The Grignard reaction was discovered by the French chemist F. A. V. Grignard in 1900. Grignard reagents are obtained by the action of Mg on alkyl or aryl halides in an ether medium and are usually used in the form of ether solutions. Methods of preparing RMgX using solvents other than ether have been worked out for industrial use. An atom of carbon bound to an atom of magnesium carries a partial negative charge δ-, so that compounds of RMgX are reactive in relation to reagents with positively charged reaction centers:

When RMgX reacts with C02, carboxylic acids are formed. With formaldehyde (CH2=0) primary alcohols are formed; with aldehydes (RCH=0), secondary alcohols; and with ketones (RR’C=0), tertiary alcohols. The use of the Grignard reaction to obtain ketones from carboxylic acids and their derivatives, for example,


is limited. It is difficult to stop the reaction at the ketone-forming stage, and ordinarily tertiary alcohols are formed in considerable quantity.

Grignard reagents react easily with halides of elements, for example.

2RMgX + HgCl2 → R2Hg + 2MgXCl

In this manner it is possible to obtain organic compounds of Be, Cd, B, Si, Ge, Pb, P, and other elements. Grignard reagents react with oxygen and sulfur to form alcohols and thioalcohols, respectively. When reacting with water, alcohols, acids, amines, and other compounds containing a labile atom of hydrogen, the RMgX decompose and hydrocarbons are formed:

RMgX + R’OH → R—H + R’OMgX

If CH3MgI is used, then it is possible to determine the amount of active hydrogen by the amount of methane released (the Chugaev-Tserevitinov method).


Ioffe, S. T., and A. N. Nesmeianov. Metody elementoorganicheskoi khimii. Moscow, 1963.
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Styring, Kinetic and Economic Analysis of Reactive Capture of Dilute Carbon Dioxide with Grignard reagents, 183 (2015)
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In 2008-2009, member Christopher Grignard was a doctoral student when Yvonne Johnson was brought into a University of Alberta classroom as a guest speaker.
Compound 4, commonly called 5-cyanophthalide, is subjected to Grignard reaction with 4-fluorophenyl magnesium bromide in tetrahydrofuran and the resulting product is treated with sodium borohydride to obtain the diol 6, which is cyclized with 2N HCl to afford 1(4-fluorophenyl)-1,3-dihydroisobenzofuran-5-carbonitrile 7.
Substitution of the fluorine atoms bonded to the boron center in 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (F-BODIPY) compounds with ethynyl or aryl linkages can be achieved through either Grignard or lithium organometallic reagents.
Among the topics are solid-phase reactions of polymer-bound arenesulfonates with aryl Grignard reagents, resin-to-resin transfer reactions through Sonogashira coupling, polyaniline-immobilized palladium for Suzuki-Miyuaura coupling reactions in water, solid-phase reactions of resin-supported boronic acids, and the palladium-catalyzed solid-phase synthesis of allelic amines.
Among these reactions are an electrophilic aromatic substitution, a Williamson ether synthesis, a Grignard coupling reaction and a Hell-Volhard-Zelinski reaction.
This represents an improvement on the well-established Grignard method for diaklylations of esters using metallic magnesium and alkyl halides.
Labeled methyl benzoate was then added dropwise to a stirred solution of methyl magnesium bromide and mixed with dry ether in a Grignard reaction.
Kipping pioneered the use of the newly discovered Grignard reagent to prepare organosilicon compounds; he reported in 1904 the first silicone polymers and described them as "sticky messes with no particular use.