Gilman reagents are particularly useful for forming new carboncarbon bonds via a coupling reaction with an alkyl chloride, bromide, or iodide (alkyl fluorides are inactive under these circumstances), as demonstrated by the following production of 2-methyl-1-dodecene.

• It's worth noting that the reaction only transfers one of the Gilman-reagent alkyl groups.

• Because Gilman reagents are eventually synthesized from halides, efficient coupling of two halides occurs.

• Gilman reagents are made up of two organic groups linked together by a copper(I) ion, resulting in a negatively charged species that serves as the source of the carbon nucleophile.

• As the counterion, lithium ion is connected with this negatively charged species.

• This example shows the reaction of a nucleophile, a Gilman reagent, with an electrophile, a vinylic halide.

• Vinylic halides are typically nonreactive to nucleophilic displacement.

• As a result, the lithium diorganocopper reaction demonstrated here is one-of-a-kind.

Gilman reagents with the highest coupling product yields are those made from methyl, primary alkyl, allylic, vinylic, and aryl halides through the respective organolithium compounds.

• Secondary and tertiary haloalkanes have lesser yields.

The orientation of the carboncarbon double bond is retained after coupling with a vinylic halide, as demonstrated by the synthesis of trans-5-tridecene.

A metal atom or ion bonds to a surrounding array of molecules known as ligands in inorganic coordination complexes.

• When a ligand directly bonds to a metal, the complex is referred to as an organometallic compound.

• The study of chemical compounds having carbon-metal linkages is known as organometallic chemistry.

The carbon-metal bond (C-M) has properties ranging from extremely ionic to covalent. Ionic bonds are more commonly observed with electropositive metals, such as Group 1 or 2 metals.

• When looking at the periodic table, the C-M bonds usually grow more covalent as you move from left to right in a row.

• Other parameters, like as charge stability, can also impact the degree of ionic or covalent bonding.

Carbon's partial negative charge makes it basic and nucleophilic; the latter trait may be used in organic synthesis to form carbon-carbon bonds.

• Grignard reagents are named after their discoverer, Victor Grignard, who discovered organomagnesium compounds.

• Grignard reagents are made by reacting alkyl, aryl, or alkenyl halides (chlorides, bromides, and iodides, not fluorides) in an ether solvent with a little excess of magnesium metal.

• Grignard reagents' carbon-magnesium bond is polar covalent, with a partial negative charge on carbon, making it nucleophilic and basic.

An alkyl, aryl, or alkenyl halide is reacted with two equivalents of lithium metal to produce organolithium reagents.

• In organolithium compounds, the carbon-lithium bond is polar covalent, with a partial negative charge on carbon, making it nucleophilic.

• Grignard reagents and organolithium compounds react as carbon nucleophiles with a broad variety of electrophilic functional groups, including epoxides (as well as numerous carbonyl-containing species addressed later in the book).

The image attached below shows a dihalocarbene that is generated by treatment of CHCl3 or CHBr3 with a strong base such as potassium tert-butoxide.

• Addition of the dihalocarbene to an alkene shows syn stereospecificity

The reaction happens at the less hindered carbon in unsymmetrical epoxides.

• Because a new carbon-carbon bond is generated, these reactions are extremely valuable for synthesis.

• Following an acidic aqueous workup, the initial product generated is an alkoxide salt, which is transformed to an alcohol product.

The image attached below shows a Treatment of CH2I2 with a zinc-copper couple generates an organozinc compound, known as the Simmons-Smith reagent, which reacts with alkenes to give cyclopropanes.

Because Grignard and organolithium reagents are extremely basic, they will deprotonate functional groups such amines, terminal alkynes, alcohols, thiols, and carboxylic acids.

• Carbenes: refers to neutral compounds that contain a carbon with just six valence electrons; carbenoids are their organometallic-complexed analogues.

Carbenes are sp2 hybridized, with one sp2 hybrid orbital containing an empty 2p orbital and a lone pair.

• Carbenes are synthesized by photolysis or thermolysis of diazo compounds such as diazomethane.

• Dichlorocarbene is made by reacting chloroform with a strong base.

The Simmons-Smith reagent, which is made from diiodomethane and Zn, is a valuable carbenoid (Cu).

• Carbenes like methylene are too reactive to be employed in synthesis.

• Cyclopropanes are formed when dichlorocarbene and the Simmons-Smith reagent react stereospecifically with alkenes.