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Oxymercuration
In organic chemistry, the oxymercuration reaction is an electrophilic addition reaction that transforms an alkene () into a neutral alcohol. In oxymercuration, the alkene reacts with mercuric acetate () in aqueous solution to yield the addition of an acetoxymercury () group and a hydroxy () group across the double bond. Carbocations are not formed in this process and thus rearrangements are not observed. The reaction follows Markovnikov's rule (the hydroxy group will always be added to the more substituted carbon). The oxymercuration part of the reaction involves anti addition of OH group but the demercuration part of the reaction involves free radical mechanism and is not stereospecific, i.e. H and OH may be syn or anti to each other. Oxymercuration followed by reductive demercuration is called an oxymercuration–reduction reaction or oxymercuration–demercuration reaction. This reaction, which is almost always done in practice instead of oxymercuration, is treated at the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxymercuration-reduction
In organic chemistry, the oxymercuration reaction is an electrophilic addition reaction that transforms an alkene () into a neutral Alcohol (chemistry), alcohol. In oxymercuration, the alkene reacts with mercuric acetate () in aqueous solution to yield the addition of an acetoxymercury () group and a Hydroxy group, hydroxy () group across the double bond. Carbocations are not formed in this process and thus rearrangements are not observed. The reaction follows Markovnikov's rule (the hydroxy group will always be added to the more substituted carbon). The oxymercuration part of the reaction involves anti addition of OH group but the demercuration part of the reaction involves free radical mechanism and is not stereospecific, i.e. H and OH may be syn or anti to each other. Oxymercuration followed by organic reduction, reductive demercuration is called an oxymercuration–reduction reaction or oxymercuration–demercuration reaction. This reaction, which is almost always done in pra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxymercuration Mechanism
In organic chemistry, the oxymercuration reaction is an electrophilic addition reaction that transforms an alkene () into a neutral alcohol. In oxymercuration, the alkene reacts with mercuric acetate () in aqueous solution to yield the addition of an acetoxymercury () group and a hydroxy () group across the double bond. Carbocations are not formed in this process and thus rearrangements are not observed. The reaction follows Markovnikov's rule (the hydroxy group will always be added to the more substituted carbon). The oxymercuration part of the reaction involves anti addition of OH group but the demercuration part of the reaction involves free radical mechanism and is not stereospecific, i.e. H and OH may be syn or anti to each other. Oxymercuration followed by reductive demercuration is called an oxymercuration–reduction reaction or oxymercuration–demercuration reaction. This reaction, which is almost always done in practice instead of oxymercuration, is treated at the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syn And Anti Addition
In organic chemistry, syn- and anti-addition are different ways in which substituent molecules can be added to an alkene () or alkyne (). The concepts of syn and anti addition are used to characterize the different reactions of organic chemistry by reflecting the stereochemistry of the products in a reaction. The type of addition that occurs depends on multiple different factors of a reaction, and is defined by the final orientation of the substituents on the parent molecule. Syn and anti addition are related to Markovnikov's rule for the orientation of a reaction, which refers to the bonding preference of different substituents for different carbons on an alkene or alkyne. In order for a reaction to follow Markovnikov's rule, the intermediate carbocation of the mechanism of a reaction must be on the more-substituted carbon, allowing the substituent to bond to the more-stable carbocation and the more-substituted carbon. Syn addition is the addition of two substituents to the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hofmann-Sand Reaction
Organomercury chemistry refers to the study of organometallic compounds that contain mercury. Many organomercury compounds are highly toxic, but some are used in medicine, e.g., merbromin ("Mercurochrome") and the vaccine preservative thiomersal. Structure and bonding Most organomercury compounds feature diamagnetic Hg(II) and adopt a linear C-Hg-X structure. Indeed, no organic derivatives of Hg are known, as Hg requires electronegative subtituents for condensed-phase stability. Hg(II) derivatives are neither Lewis basic or Lewis acidic. They are stable to oxygen and water, indicating the low polarity of the Hg-C bond. Mercury forms a compound with two cyclopentadiene ligands, but the resulting complex may not be a metallocene. When made in the 1950s, it was too sensitive for structural determination. Toxicity The toxicity of organomercury compounds presents both dangers and benefits. Dimethylmercury in particular is notoriously toxic, but found use as an antifungal ag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alcohol (chemistry)
In chemistry, an alcohol (), is a type of organic compound that carries at least one hydroxyl () functional group bound to a Saturated and unsaturated compounds, saturated carbon atom. Alcohols range from the simple, like methanol and ethanol, to complex, like sugar alcohols and cholesterol. The presence of an OH group strongly modifies the properties of Hydrocarbon, hydrocarbons, conferring Hydrophile, hydrophilic (water-loving) properties. The OH group provides a site at which many reactions can occur. History The flammable nature of the exhalations of wine was already known to ancient natural philosophers such as Aristotle (384–322 BCE), Theophrastus (–287 BCE), and Pliny the Elder (23/24–79 CE). However, this did not immediately lead to the isolation of alcohol, even despite the development of more advanced distillation techniques in second- and third-century Roman Egypt. An important recognition, first found in one of the writings attributed to Jabir ibn Hayyan, J� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercuric Acetate
Mercury(II) acetate, also known as mercuric acetate is a chemical compound, the mercury(II) salt of acetic acid, with the formula Hg( O2 CC H3)2. Commonly abbreviated Hg(OAc)2, this compound is employed as a reagent to generate organomercury compounds from unsaturated organic precursors. It is a white, water-soluble solid, but some samples can appear yellowish with time owing to decomposition. Structure Mercury(II) acetate is a crystalline solid consisting of isolated Hg(OAc)2 molecules with Hg-O distances of 2.07 Å. Three long, weak intermolecular Hg···O bonds of about 2.75 Å are also present, resulting in a slightly distorted square pyramidal coordination geometry at Hg. Synthesis and reactions Mercury(II) acetate can be produced by reaction of mercuric oxide with acetic acid. HgO + 2 CH3COOH → Hg(CH3COO)2 + H2O Inorganic reactions Mercury(II) acetate in acetic acid solution reacts with H2S to rapidly precipitate the black (β) polymorph of HgS. Wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Onium Ion
In chemistry, an onium ion is a cation formally obtained by the protonation of mononuclear parent hydride of a pnictogen (group 15 of the periodic table), chalcogen (group 16), or halogen (group 17). The oldest-known onium ion, and the namesake for the class, is ammonium, , the protonated derivative of ammonia, . The name onium is also used for cations that would result from the substitution of hydrogen atoms in those ions by other groups, such as organic groups, or halogens; such as tetraphenylphosphonium, . The substituent groups may be divalent or trivalent, yielding ions such as iminium and nitrilium. A simple onium ion has a charge of +1. A larger ion that has two onium ion subgroups is called a double onium ion, and has a charge of +2. A triple onium ion has a charge of +3, and so on. Compounds of an onium cation and some other anion are known as onium compounds or onium salts. Onium ions and onium compounds are inversely analogous to ions and ate complexe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclohexane Conformation
Cyclohexane conformations are any of several three-dimensional shapes adopted by cyclohexane. Because many compounds feature structurally similar six-membered rings, the structure and dynamics of cyclohexane are important prototypes of a wide range of compounds. The internal angles of a regular, flat hexagon are 120°, while the preferred angle between successive bonds in a carbon chain is about 109.5°, the tetrahedral angle (the arc cosine of −). Therefore, the cyclohexane ring tends to assume non-planar (warped) conformations, which have all angles closer to 109.5° and therefore a lower strain energy than the flat hexagonal shape. Consider the carbon atoms numbered from 1 to 6 around the ring. If we hold carbon atoms 1, 2, and 3 stationary, with the correct bond lengths and the tetrahedral angle between the two bonds, and then continue by adding carbon atoms 4, 5, and 6 with the correct bond length and the tetrahedral angle, we can vary the three dihedral angles f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Borohydride
Sodium borohydride, also known as sodium tetrahydridoborate and sodium tetrahydroborate, is an inorganic compound with the formula (sometimes written as ). It is a white crystalline solid, usually encountered as an aqueous basic solution. Sodium borohydride is a reducing agent that finds application in papermaking and dye industries. It is also used as a reagent in organic synthesis. The compound was discovered in the 1940s by H. I. Schlesinger, who led a team seeking volatile uranium compounds.Hermann I Schlesinger and Herbert C Brown (1945)Preparation of alkali metal compounds. US Patent 2461661. Granted on 1949-02-15; expired on 1966-02-15. Results of this wartime research were declassified and published in 1953. Properties The compound is soluble in alcohols, certain ethers, and water, although it slowly hydrolyzes. Sodium borohydride is an odorless white to gray-white microcrystalline powder that often forms lumps. It can be purified by recrystallization from warm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
