Vinyllithium

Last updated
Vinyllithium
Vinyllithium.png
Identifiers
3D model (JSmol)
3587231
ChEBI
ChemSpider
EC Number
  • 213-028-5
723
PubChem CID
  • InChI=1S/C2H3.Li/c1-2;/h1H,2H2;
    Key: PGOLTJPQCISRTO-UHFFFAOYSA-N
  • [Li]C=C
Properties
C2H3Li
Molar mass 33.99 g·mol−1
Appearancewhite solid
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
pyrophoric
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Vinyllithium is an organolithium compound with the formula LiC2H3. A colorless or white solid, it is encountered mainly as a solution in tetrahydrofuran (THF). It is a reagent in synthesis of organic compounds, especially for vinylations. [1]

Contents

Preparation and structure

Solutions of vinyllithium are prepared by lithium-halogen exchange reactions. A halide-free route entails reaction of tetravinyltin with butyllithium:

Sn(CH=CH2)4 + 4 BuLi → SnBu4 + 4 LiCH=CH2

The reaction of ethylene and lithium affords vinyl lithium and lithium hydride, together with other organolithium compounds, [1]

Like most organolithium compounds, vinyllithium crystallizes from THF as a cluster compound as a cubane-type cluster. [2]

Structure of [LiC2H3(THF)]4. PAFCEE.png
Structure of [LiC2H3(THF)]4.

Reactions

Vinyllithium is used to install vinyl groups on metal-based reagents, i.e., vinylations. It is a precursor to vinylsilanes, vinylcuprates, and vinylstannanes. [3] It adds to ketones compounds to give allylic alcohols. Vinylmagnesium bromide is often used in place of vinyllithium. [4]

Alternative reagents

Vinyl magnesium bromide, a Grignard reagent, is in many ways easier to generate in the laboratory and behaves similarly to vinyllithium. [5]

Related Research Articles

<span class="mw-page-title-main">Gilman reagent</span> Class of chemical compounds

A Gilman reagent is a lithium and copper (diorganocopper) reagent compound, R2CuLi, where R is an alkyl or aryl. These reagents are useful because, unlike related Grignard reagents and organolithium reagents, they react with organic halides to replace the halide group with an R group (the Corey–House reaction). Such displacement reactions allow for the synthesis of complex products from simple building blocks.

<span class="mw-page-title-main">Organolithium reagent</span> Chemical compounds containing C–Li bonds

In organometallic chemistry, organolithium reagents are chemical compounds that contain carbon–lithium (C–Li) bonds. These reagents are important 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. Owing to the polar nature of the C−Li bond, organolithium reagents are 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.

In organometallic chemistry, acetylide refers to chemical compounds with the chemical formulas MC≡CH and MC≡CM, where M is a metal. The term is used loosely and can refer to substituted acetylides having the general structure RC≡CM. Acetylides are reagents in organic synthesis. The calcium acetylide commonly called calcium carbide is a major compound of commerce.

<span class="mw-page-title-main">Organotin chemistry</span> Branch of organic chemistry

Organotin chemistry is the scientific study of the synthesis and properties of organotin compounds or stannanes, which are organometallic compounds containing tin carbon bonds. The first organotin compound was diethyltin diiodide, discovered by Edward Frankland in 1849. The area grew rapidly in the 1900s, especially after the discovery of the Grignard reagents, which are useful for producing Sn–C bonds. The area remains rich with many applications in industry and continuing activity in the research laboratory.

<i>n</i>-Butyllithium Chemical compound

n-Butyllithium C4H9Li (abbreviated n-BuLi) is an organolithium reagent. It is widely used as a polymerization initiator in the production of elastomers such as polybutadiene or styrene-butadiene-styrene (SBS). Also, it is broadly employed as a strong base (superbase) in the synthesis of organic compounds as in the pharmaceutical industry.

<span class="mw-page-title-main">1-Bromobutane</span> Chemical compound

1-Bromobutane is the organobromine compound with the formula CH3(CH2)3Br. It is a colorless liquid, although impure samples appear yellowish. It is insoluble in water, but soluble in organic solvents. It is primarily used as a source of the butyl group in organic synthesis. It is one of several isomers of butyl bromide.

The Trapp mixture is a specific mixture of organic solvents that allows chemical reactions to take place at very low temperatures. It is made up of THF:diethyl ether:pentane in a 4:4:1 ratio which remains liquid down to −110 °C and the same solvents in a 4:1:1 ratio remain a liquid down to −120 °C. This solvent system retains a low viscosity until just before freezing and it allows a lower temperature reaction than pure THF, which melts at −108.4 °C. An illustrative application of Trapp solvent is the preparation of vinyllithium by lithium halogen exchange from vinyl bromide and tert-butyllithium. The low temperatures suppress the reaction of the strongly basic organolithium reagent with the THF.

<span class="mw-page-title-main">Hydroperoxide</span> Class of chemical compounds

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<i>tert</i>-Butyllithium Chemical compound

tert-Butyllithium is a chemical compound with the formula (CH3)3CLi. As an organolithium compound, it has applications in organic synthesis since it is a strong base, capable of deprotonating many carbon molecules, including benzene. tert-Butyllithium is available commercially as hydrocarbon solutions; it is not usually prepared in the laboratory.

<span class="mw-page-title-main">Grignard reagent</span> Organometallic compounds used in organic synthesis

A Grignard reagent or Grignard compound is a chemical compound with the general formula R−Mg−X, where X is a halogen and R is an organic group, normally an alkyl or aryl. Two typical examples are methylmagnesium chloride Cl−Mg−CH3 and phenylmagnesium bromide (C6H5)−Mg−Br. They are a subclass of the organomagnesium compounds.

The Finkelstein reaction named after the German chemist Hans Finkelstein, is an SN2 reaction that involves the exchange of one halogen atom for another. It is an equilibrium reaction, but the reaction can be driven to completion by exploiting the differential solubility of halide salts, or by using a large excess of the halide salt.

<span class="mw-page-title-main">Organocopper chemistry</span> Compound with carbon to copper bonds

Organocopper chemistry is the study of the physical properties, reactions, and synthesis of organocopper compounds, which are organometallic compounds containing a carbon to copper chemical bond. They are reagents in organic chemistry.

<i>sec</i>-Butyllithium Chemical compound

sec-Butyllithium is an organometallic compound with the formula CH3CHLiCH2CH3, abbreviated sec-BuLi or s-BuLi. This chiral organolithium reagent is used as a source of sec-butyl carbanion in organic synthesis.

<span class="mw-page-title-main">Group 2 organometallic chemistry</span>

Group 2 organometallic chemistry refers to the chemistry of compounds containing carbon bonded to any group 2 element. By far the most common group 2 organometallic compounds are the magnesium-containing Grignard reagents which are widely used in organic chemistry. Other organmetallic group 2 compounds are rare and are typically limited to academic interests.

<span class="mw-page-title-main">Trimethyltin chloride</span> Chemical compound

Trimethyltin chloride is an organotin compound with the formula (CH3)3SnCl. It is a white solid that is highly toxic and malodorous. It is susceptible to hydrolysis.

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Propynyllithium is an organolithium compound with the chemical formula LiC
2
CH
3
. It is a white solid that is soluble in 1,2-dimethoxyethane, and tetrahydrofuran. To preclude its degradation by oxygen and water, propynyllithium and its solutions are handled under inert gas. Although commonly depicted as a monomer, propynyllithium adopts a more complicated cluster structure as seen for many other organolithium compounds.

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<span class="mw-page-title-main">Vinyl tributyltin</span> Chemical compound

Vinyl tributyltin is an organotin compound with the formula Bu3SnCH=CH2 (Bu = butyl). It is a white, air-stable solid. It is used as a source of vinyl anion equivalent in Stille coupling reactions. As a source of vinyltin reagents, early work used vinyl trimethyltin, but trimethyltin compounds are avoided nowadays owing to their toxicity.

In organometallic chemistry, metal–halogen exchange is a fundamental reaction that converts an organic halide into an organometallic product. The reaction commonly involves the use of electropositive metals and organochlorides, bromides, and iodides. Particularly well-developed is the use of metal–halogen exchange for the preparation of organolithium compounds.

References

  1. 1 2 Eisenhart, Eric K.; Bessieres, Bernard (2007). "Vinyllithium". E-EROS Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rv015.pub2. ISBN   978-0-471-93623-7..
  2. Walter Bauer; Frank Hampel (1992). "X-Ray crystal structure of a vinyllithium–tetrahydrofuran solvate (C2H3Li–thf)4. Quantitative estimation of Li–H distances by 6Li–1H HOESY". J. Chem. Soc., Chem. Commun. (12): 903–905. doi:10.1039/C39920000903.
  3. Lipshutz, Bruce H.; Moretti, Robert; Crow, Robert (1990). "Mixed Higher-order Cyanocuprate-induced Epoxide Openings: 1-benzyloxy-4-penten-2-ol". Org. Synth. 69: 80. doi:10.15227/orgsyn.069.0080.
  4. Dietmar Seyferth (1959). "Di-n-butyldivinyltin". Org. Synth. 39: 10. doi:10.15227/orgsyn.039.0010.
  5. William J. Scott, G. T. Crisp, J. K. Stille (1990). "Palladium-catalyzed Coupling of Vinyl Triflates with Organostannanes: 4-tert-Butyl-1-Vinylcyclohexene and 1-(4-tert-Butylcyclohexen-1-yl)-2-propen-1-one". Organic Syntheses. 68: 116. doi:10.15227/orgsyn.068.0116.{{cite journal}}: CS1 maint: multiple names: authors list (link)