Liebeskind-Srogl cross coupling

What is Liebeskind-Srogl Cross Coupling?

The Liebeskind-Srogl (LS) cross coupling is a chemical reaction that involves the coupling of an organometallic compound, such as an alkyl or aryl lithium, with an organic halide, such as an alkyl or aryl halide, to form a diaryl or alkyl-alkyl compound. It is named after the American chemists Joshua S. Liebeskind and Jeffrey A. Srogl, who first described the reaction in their research on the synthesis of organometallic compounds..

The LS cross coupling is a useful method for synthesizing diaryl and alkyl-alkyl compounds, which are important intermediates in the production of a wide range of chemicals and pharmaceuticals. It is a two-step process that involves the formation of an organometallic compound, followed by the coupling of the organometallic compound with an organic halide..

The first step of the LS cross coupling involves the formation of an organometallic compound, such as an alkyl or aryl lithium, from a metal, such as lithium or magnesium, and an organic compound, such as an alkyl or aryl halide. This is typically done by reacting the metal with the organic compound in the presence of a solvent, such as tetrahydrofuran or hexane. The resulting organometallic compound is a strong reducing agent and can be used in the second step of the reaction..

The second step of the LS cross coupling involves the coupling of the organometallic compound with an organic halide, such as an alkyl or aryl halide. This is typically done by reacting the organometallic compound with the organic halide in the presence of a solvent. The resulting product is a diaryl or alkyl-alkyl compound, with the organic groups coupled through a metal bond..

The LS cross coupling has several advantages over other methods of synthesizing diaryl and alkyl-alkyl compounds. It is a straightforward and efficient process that can be easily scaled up for large-scale production. It also allows for the synthesis of a wide range of diaryl and alkyl-alkyl compounds, with good yields and good selectivity..

Despite these advantages, the LS cross coupling has some limitations. It is not suitable for the synthesis of diaryl and alkyl-alkyl compounds from organometallic compounds with certain substituents, such as halogens, due to the high reactivity of the intermediates. It is also not suitable for the synthesis of diaryl and alkyl-alkyl compounds from organic halides with certain substituents, such as electron-withdrawing groups, due to the low reactivity of the organic halides..

Summary

The LS cross coupling is an important method for the synthesis of diaryl and alkyl-alkyl compounds, and it has played a significant role in the production of a wide range of chemicals and pharmaceuticals..

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