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. Organometallics addition to a carbonyl group organolithium reagent controls.
Methyllithium is an organolithium reagent mainly used for deprotonation and as a source of methyl anion.
Meli reagent. Operations involving methyllithium require anhydrous conditions because the compound is highly reactive toward water. The basic reaction involves the nucleophilic attack of the carbanionic carbon in the organometallic reagent with the electrophilic carbon in the carbonyl to form alcohols. It is a strong base and a strong nucleophile.
Pubchem substance id 24873753. Application methyllithium solution 1 6m in diethyl ether has been used for the asymmetric allylic alkylation aaa of allylic electrophiles in the presence of a chiral copper catalyst. The metal atom will coordinate with the negatively charged oxygen atom.
The nucleophilic c in the organometallic reagent adds to theelectrophilic c in the polar carbonyl group of the ester electrons from the c o move to the electronegative o creating thetetrahderal intermediate a metal alkoxide complex. Firstly the meli reacts with the ethanal to form the alkoxide. Because organometallic reagents react as their corresponding carbanion they are excellent nucleophiles.
This s block organometallic compound adopts an oligomeric structure both in solution and in the solid state. Simple organolithium reagents meli phli n buli sec buli t buli and a few others are usually made by the reduction of halides normally chlorides with lithium. Both grignard and organolithium reagents will perform these reactions.
However several very effective lithium arene reagents or catalysts such as 4 4 di t. This highly reactive compound invariably used as a solution in ethers is a reagent in organic synthesis as well as organometallic chemistry. The tetrahedral intermediate collapses and displaces the alcohol portion of the ester as a leaving group in the form of the alkoxide ro this.
Empirical formula hill notation ch 3 li. Organolithium reagents are organometallic compounds that contain carbon lithium bonds. Oxygen and carbon dioxide are also incompat.
An organolithium reagent is an organometallic compound with a direct bond between a carbon and a lithium atom. Methyllithium is the simplest organolithium reagent with the empirical formula ch3li. Lithium methanide meli cas number 917 54 4.
Water is then added to protonate the. Methyllithium is shown below reacting with an aldehyde. Organolithium reagents are used in industry as an initiator for anionic polymerization.
The direct reaction of lithium metal with more complex substrates is difficult. This is the work up step a simple acid base reaction. Beilstein reaxys number 3587162.
Molecular weight 21 98. The nucleophilic c in the organometallic reagent adds to the electrophilic c in the polar carbonyl group electrons from the c o move to the electronegative o creating an intermediate metal alkoxide complex. As the electropositive nature of lithium puts most of the charge density of the bond on the carbon atom effectively creating a carbanion organolithium compounds are extremely powerful bases and nucleophiles.