Lithium dichloro(1-methylethyl)-magnesate(1-)
[CAS# 745038-86-2]

Identification

• Classification: Organic raw materials >> Organometallic compound >> Organomagnesium
• Name: Lithium dichloro(1-methylethyl)-magnesate(1-)
• Synonyms: 745038-86-2
• Molecular Formula: C₃H₇Cl₂Mg.Li
• Molecular Weight: 145.24
• CAS Registry Number: 745038-86-2
• EC Number: 695-413-1
• SMILES: [Li]Cl.CC(C)[Mg]Cl

Properties

• Density: 0.951 g/mL (25 °C) (Expl.)
• Flash point: -17 °C (Expl.)

Safety Data

• Hazard Symbols: GHS02;GHS08;GHS05;GHS07 Danger
• Risk Statements: H225-H314-H335-H336-H351
• Safety Statements: P202-P210-P280-P303+P361+P353-P304+P340+P310-P305+P351+P338

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin corrosion	Skin Corr.	1B	H314
Skin corrosion	Skin Corr.	1A	H314
Pyrophoric solids	Pyr. Sol.	1	H250
Substances or mixtures which in contact with water emit flammable gases	Water-react.	1	H260
Flammable liquids	Flam. Liq.	2	H225
Serious eye damage	Eye Dam.	1	H318

Discovery and Applications

Lithium dichloro(1-methylethyl)-magnesate(1-) is a complex organomagnesium compound widely utilized in modern synthetic organic chemistry. This reagent, commonly referred to in synthetic contexts as a lithium magnesate or mixed organomagnesium complex, combines the reactive properties of Grignard reagents with the stabilizing influence of lithium salts. Its unique structure, featuring a magnesium center coordinated by two chloride ions, an isopropyl group, and a lithium counterion, imparts enhanced reactivity and selectivity in various chemical transformations.

The origins of organomagnesium chemistry date back to Victor Grignard's discovery of Grignard reagents in the early 20th century. Subsequent research extended these concepts to the development of lithium magnesates, which benefit from synergistic interactions between magnesium and lithium ions. These complexes emerged as versatile tools for achieving highly controlled reactions, particularly in challenging bond-forming processes.

Lithium dichloro(1-methylethyl)-magnesate(1-) is prepared by combining isopropylmagnesium chloride (a Grignard reagent) with lithium chloride in an aprotic solvent such as tetrahydrofuran (THF). This formation stabilizes the organomagnesium species, broadening its compatibility with diverse substrates and enhancing its utility in multi-step synthesis. The lithium chloride plays a key role by coordinating with the magnesium center, modulating reactivity, and facilitating solubility in organic solvents.

This compound is widely applied in organic synthesis, particularly in regioselective and stereoselective transformations. Its dual metal composition provides unique reactivity profiles compared to conventional Grignard reagents, enabling selective alkylation, arylation, and addition reactions to carbonyl compounds, imines, and other electrophilic substrates. Its isopropyl group contributes to nucleophilic attack in reactions, offering an ideal balance of steric hindrance and reactivity.

One of its prominent uses is in the synthesis of tertiary alcohols, where it reacts with ketones to form products with high regio- and stereoselectivity. These tertiary alcohols often serve as intermediates in pharmaceuticals, agrochemicals, and advanced materials. Additionally, the reagent finds applications in cross-coupling reactions and as a base in deprotonation steps for the preparation of enolates or other reactive intermediates.

Lithium dichloro(1-methylethyl)-magnesate(1-) is also valuable in synthesizing complex organometallic frameworks and polymer precursors. Its unique reactivity enables precise functionalization of small molecules and polymers, contributing to materials science innovations. Furthermore, it has been investigated for use in the formation of chiral centers in asymmetric synthesis, where its combination of magnesium and lithium ions promotes distinct reaction pathways.

Handling this compound requires careful attention to moisture- and air-free conditions, as it is highly sensitive and reactive. Its stability in solution, however, makes it an ideal candidate for large-scale industrial processes, provided proper precautions are in place.

Lithium dichloro(1-methylethyl)-magnesate(1-) exemplifies the advancements in organometallic chemistry, offering chemists a powerful tool for precise molecular construction. Its continued development and application highlight its importance in advancing synthetic methodologies across multiple chemical disciplines.

References

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