Lithiation

Organolithium reagents are organometallic compounds that contain carbon – lithium bonds. They are important reagents in organic synthesis, and are frequently used to transfer the organic group or the lithium atom to the substrates in synthetic steps, through nucleophilic addition or simple deprotonation. Organolithium reagents are used in industry as an initiator for anionic polymerization, which leads to the production of various elastomers. They have also been applied in asymmetric synthesis in the pharmaceutical industry.

Due to the large difference in electronegativity between the carbon atom and the lithium atom, the C-Li bond is highly ionic. This extremely polar nature of the C-Li bond makes organolithium reagents good nucleophiles and strong bases. For laboratory organic synthesis, many organolithium reagents are commercially available in solution form. These reagents are highly reactive, and are sometimes pyrophoric.

Studies of organolithium reagents began in the 1930 and were pioneered by Karl Ziegler, Georg Wittig, and Henry Gilman. These chemists found that in comparison with Grignard reagents, organolithium reagents can often perform the same reactions with increased rates and higher yields, such as in the case of metalation. Since then, organolithium reagents have surpassed Grignard reagents in usage. Ongoing research focuses on the nature of carbon-lithium bonding, structural studies of organolithium aggregates, chiral organolithium reagents and asymmetric synthesis, and the role of organolithium reagents in the preparation of new organometallic species.

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