Ethylmagnesium bromide
[CAS# 925-90-6]

Identification

• Classification: Organic raw materials >> Organometallic compound >> Organomagnesium
• Name: Ethylmagnesium bromide
• Molecular Formula: C₂H₅BrMg
• Molecular Weight: 133.27
• CAS Registry Number: 925-90-6
• EC Number: 213-127-3
• SMILES: C[CH2-].[Mg+2].[Br-]

Properties

• Density: 1.02 g/mL (25 °C) (Expl.)
• Flash point: -40 °C (closed cup) (Expl.)

Safety Data

• Hazard Symbols: GHS02;GHS05 Danger
• Risk Statements: H225-H260-H314
• Safety Statements: P210-P223-P231+P232-P233-P240-P241-P242-P243-P260-P264-P280-P301+P330+P331-P302+P335+P334-P302+P361+P354-P303+P361+P353-P304+P340-P305+P354+P338-P316-P321-P363-P370+P378-P402+P404-P403+P235-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Substances or mixtures which in contact with water emit flammable gases	Water-react.	1	H260
Skin corrosion	Skin Corr.	1B	H314
Flammable liquids	Flam. Liq.	2	H225
Serious eye damage	Eye Dam.	1	H318
Skin corrosion	Skin Corr.	1	H314
Substances or mixtures which in contact with water emit flammable gases	Water-react.	2	H261

• Transport Information: UN 3399

Discovery and Applications

Ethylmagnesium bromide is a widely utilized organometallic reagent classified as a Grignard reagent. It is a solution, typically in diethyl ether or tetrahydrofuran (THF), and plays a crucial role in organic synthesis. The reagent's discovery traces back to Victor Grignard in 1900, whose pioneering work with magnesium alkyl and aryl halides earned him the Nobel Prize in Chemistry in 1912. Ethylmagnesium bromide, like other Grignard reagents, has since become indispensable in the formation of carbon-carbon bonds and a variety of other chemical transformations.

The preparation of ethylmagnesium bromide involves the reaction of ethyl bromide with magnesium metal in an anhydrous solvent like diethyl ether. The highly reactive nature of the magnesium center facilitates the generation of the ethylmagnesium bromide complex. The reaction is exothermic and requires careful handling due to the flammable nature of the reagents and the sensitivity of the Grignard reagent to moisture and air.

In organic synthesis, ethylmagnesium bromide is employed as a nucleophile to add ethyl groups to electrophiles, including aldehydes, ketones, esters, and carbon dioxide. This reaction is fundamental in the synthesis of alcohols. For instance, the addition of ethylmagnesium bromide to formaldehyde yields ethanol, while its reaction with acetone produces 2-butanol. It is also utilized in the preparation of carboxylic acids through reaction with carbon dioxide and in the synthesis of alkanes via protonation.

Ethylmagnesium bromide is also notable for its role in industrial chemistry. It is used to produce intermediates for pharmaceuticals, agrochemicals, and polymers. Its ability to form complex molecular frameworks makes it a cornerstone in the development of active pharmaceutical ingredients (APIs) and fine chemicals. Additionally, the reagent finds applications in organometallic coupling reactions, such as the Kumada coupling, which is pivotal in creating biaryl compounds.

Despite its utility, ethylmagnesium bromide poses challenges due to its high reactivity. Handling requires an inert atmosphere, such as argon or nitrogen, to prevent degradation by oxygen or moisture. Advances in reagent formulation, such as stabilizing solutions and alternative solvents, continue to improve its usability and safety.

Ethylmagnesium bromide exemplifies the power of Grignard chemistry in modern synthetic methodologies. Its ability to form carbon-carbon bonds and its versatility in diverse chemical transformations highlight its enduring importance in both academic research and industrial applications.

References

2024. Synthesis of macrocyclic mono- and diolides based on new ω-hydroxyalkadienoic acids with (Z,Z)-1,5-diene moiety. Russian Chemical Bulletin, 73(6).
DOI: 10.1007/s11172-024-4278-7

2024. Reactions of substituted 1-alkynylphosphines with Et2Zn catalyzed by the Cp2ZrCl2—EtMgBr system. Russian Chemical Bulletin, 73(7).
DOI: 10.1007/s11172-024-4307-6

2023. Synthesis of macrocyclic and linear compounds with 1Z,5Z-diene and alkynylcarbinol fragments based on (5Z,9Z)-tetradeca-5,9-diene-1,14-diol. Russian Chemical Bulletin, 72(4).
DOI: 10.1007/s11172-023-3855-1