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Vinyl Lithium
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.. 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, Like most organolithium compounds, vinyllithium crystallizes from THF as a cluster compound as a cubane-type cluster. Reactions Vinyllithium is used to install vinyl groups on metal-based reagents, i.e., vinylations. It is a precursor to vinylsilanes, vinylcuprates, and vinylstannanes. It adds to ketones compounds to give allylic alcohols. Vinylmagnesium bromide is often used in place ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organolithium Compound
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. History and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrahydrofuran
Tetrahydrofuran (THF), or oxolane, is an organic compound with the formula (CH2)4O. The compound is classified as heterocyclic compound, specifically a cyclic ether. It is a colorless, water- miscible organic liquid with low viscosity. It is mainly used as a precursor to polymers. Being polar and having a wide liquid range, THF is a versatile solvent. It is an isomer of another solvent, butanone. Production About 200,000 tonnes of tetrahydrofuran are produced annually. The most widely used industrial process involves the acid-catalyzed dehydration of 1,4-Butanediol, 1,4-butanediol. Ashland Inc., Ashland/ISP is one of the biggest producers of this chemical route. The method is similar to the production of diethyl ether from ethanol. The butanediol is derived from Condensation reaction, condensation of acetylene with formaldehyde followed by hydrogenation. DuPont developed a process for producing THF by oxidizing Butane#Isomers, ''n''-butane to crude maleic anhydride, follow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reagent
In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a substance ''consumed'' in the course of a chemical reaction. ''Solvents'', though involved in the reaction mechanism, are usually not called reactants. Similarly, ''catalysts'' are not consumed by the reaction, so they are not reactants. In biochemistry, especially in connection with enzyme-catalyzed reactions, the reactants are commonly called substrates. Definitions Organic chemistry In organic chemistry, the term "reagent" denotes a chemical ingredient (a compound or mixture, typically of inorganic or small organic molecules) introduced to cause the desired transformation of an organic substance. Examples include the Collins reagent, Fenton's reagent, and Grignard reagents. Analytical chemistry In analytical chemistry, a reag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Synthesis
Organic synthesis is a branch of chemical synthesis concerned with the construction of organic compounds. Organic compounds are molecules consisting of combinations of covalently-linked hydrogen, carbon, oxygen, and nitrogen atoms. Within the general subject of organic synthesis, there are many different types of synthetic routes that can be completed including total synthesis, Enantioselective synthesis, stereoselective synthesis, automated synthesis, and many more. Additionally, in understanding organic synthesis it is necessary to be familiar with the methodology, techniques, and applications of the subject. Total synthesis A total synthesis refers to the complete chemical synthesis of molecules from simple, Precursor (chemistry), natural precursors. Total synthesis is accomplished either via a linear or convergent approach. In a Linear synthesis, ''linear'' synthesis—often adequate for simple structures—several steps are performed sequentially until the molecule is com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vinylation
In organic chemistry, vinylation is the process of attaching a vinyl group () to a substrate. Many organic compounds contain vinyl groups, so the process has attracted significant interest, especially since the reaction scope includes substituted vinyl groups. The reactions can be classified according to the source of the vinyl group. Nucleophilic vinyl reagents Vinyl lithium and vinyl magnesium bromide are sources of "", which add to ketones and aldehydes. Vinylsiloxane and vinylboranes have also been used as sources of vinyl anion equivalents.These types of reactions require catalysts such as those based on palladium. Vinylation with alkenes The Heck reaction couples an unsaturated halide with an alkene. Base and a palladium catalyst are required. This reaction is a way to substitute alkenes. Vinylation with acetylene As originally developed by Walter Reppe, acetylene participates in a variety of metal- or base-catalyzed reaction to afford vinyl derivatives. Alcoho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetravinyltin
Tetravinyltin (also known as tetravinylstannane) is an organotin compound with a chemical formula of C8H12Sn. Uses Upon heating, a mixture of tetravinyltin and tin tetrachloride undergo disproportionation to form divinyltin dichloride, vinyltin trichloride, and trivinyltin chloride in high yields. A study about this can be found in the Journal of American Chemical Society. Tetravinyltin cannot be used for therapeutic or diagnostic purposes and must only be used for research. It can also be used for thin film deposition. Hazards According to the European Chemicals Agency, tetravinyltin is flammable in liquid and gas form. It is also toxic when in contact with skin, inhaled, and swallowed. Therefore, personal protective equipment must be used in handling and proper caution applied during use. References {{reflist External links TETRAVINYLTIN - ChemicalBookTetravinylstannaneat ''Encyclopedia of Reagents for Organic Synthesis'' Stannane, tetraethenylat NIST The National Ins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Butyllithium
Butyllithium may refer to one of 5 isomeric organolithium reagents of which 3 are commonly used in chemical synthesis: * ''n''-Butyllithium, abbreviated BuLi or nBuLi * ''sec''-Butyllithium, abbreviated ''sec''-BuLi or sBuLi, has 2 stereoisomers, but is commonly used as racemate * ''tert''-Butyllithium, abbreviated ''tert''-BuLi or tBuLi * Isobutyllithium {{Chemistry index ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cubane-type Cluster
A cubane-type cluster is an arrangement of atoms in a molecular structure that forms a cube. In the simplest case, the eight vertices are symmetry equivalent and the species has Oh symmetry group, symmetry. Such structure occurs in the hydrocarbon cubane (chemical formula ), which has carbon atoms at the corners of a cube and covalent bonds forming the edges. : Other compounds in the class have different elements in the corners, and various atoms or groups bonded to the corners. Most cubanes have more complicated structures, usually with nonequivalent vertices. They may be simple covalent compounds or macromolecular or supramolecular cluster compounds. Examples Heavier adamantogen cubanes with all vertices identical are all known, and exhibit only about half as much strain energy as cubane per molecule. The inert pair effect is believed to drive stability in cubanes with heavy main group elements: the bonding orbitals are almost entirely orbital hybridization, unhybridized ''p' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grignard Reagent
Grignard reagents or Grignard compounds are chemical compounds with the general formula , where X is a halogen and R is an organic group, normally an alkyl or aryl. Two typical examples are methylmagnesium chloride and phenylmagnesium bromide . They are a subclass of the organomagnesium compounds. Grignard compounds are popular reagents in organic synthesis for creating new carbon–carbon bonds. For example, when reacted with another halogenated compound in the presence of a suitable catalyst, they typically yield and the magnesium halide as a byproduct; and the latter is insoluble in the solvents normally used. Grignard reagents are rarely isolated as solids. Instead, they are normally handled as solutions in solvents such as diethyl ether or tetrahydrofuran using air-free techniques. Grignard reagents are complex with the magnesium atom bonded to two ether ligands as well as the halide and organyl ligands. The discovery of the Grignard reaction in 1900 was recogn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organolithium Compounds
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. History and deve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
