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Prévost Reaction
The Prévost reaction is chemical reaction in which an alkene is converted by iodine and the silver salt of benzoic acid to a vicinal diol with anti stereochemistry. The reaction was discovered by the French chemist Charles Prévost (1899–1983). Reaction mechanism The reaction between silver benzoate (1) and iodine is very fast and produces a very reactive iodinium benzoate intermediate (2). The reaction of the iodinium salt (2) with an alkene gives another short-lived iodinium salt (3). Nucleophilic substitution ( SN2) by the benzoate salt gives the ester (4). Another silver ion causes the neighboring group substitution of the benzoate ester to give the oxonium salt (5). A second SN2 substitution by the benzoate anion gives the desired diester (6). In the final step hydrolysis of the ester groups gives the anti-diol. This outcome is the opposite of that of the related Woodward cis-hydroxylation which gives syn addition In organic chemistry, syn- and anti-additio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Reaction
A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the Atomic nucleus, nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive Chemical element, elements where both electronic and nuclear changes can occur. The substance (or substances) initially involved in a chemical reaction are called reagent, reactants or reagents. Chemical reactions are usually characterized by a chemical change, and they yield one or more Product (chemistry), products, which usually have properties different from the reactants. Reactions often consist of a sequence o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SN2 Reaction
The SN2 reaction is a type of reaction mechanism that is common in organic chemistry. In this mechanism, one bond is broken and one bond is formed in a concerted way, i.e., in one step. The name SN2 refers to the Hughes-Ingold symbol of the mechanism: "SN" indicates that the reaction is a nucleophilic substitution, and "2" that it proceeds via a bi-molecular mechanism, which means both the reacting species are involved in the rate-determining step. The other major type of nucleophilic substitution is the SN1, but many other more specialized mechanisms describe substitution reactions. The SN2 reaction can be considered as an analogue of the associative substitution in the field of inorganic chemistry. Reaction mechanism The reaction most often occurs at an aliphatic sp3 carbon center with an electronegative, stable leaving group attached to it (often denoted X), which is frequently a halide atom. The breaking of the C–X bond and the formation of the new bond (often deno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Redox Reactions
Organic may refer to: * Organic, of or relating to an organism, a living entity * Organic, of or relating to an anatomical organ Chemistry * Organic matter, matter that has come from a once-living organism, is capable of decay or is the product of decay, or is composed of organic compounds * Organic compound, a compound that contains carbon ** Organic chemistry, chemistry involving organic compounds Farming, certification and products * Organic farming, agriculture conducted according to certain standards, especially the use of stated methods of fertilization and pest control * Organic certification, accreditation process for producers of organically-farmed products * Organic horticulture, the science and art of growing fruits, vegetables, flowers, or ornamental plants by following the essential principles of organic agriculture * Organic products, "organics": ** Organic food, food produced from organic farming methods and often certified organic according to organic farming stand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syn 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 the 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 same ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Woodward Cis-hydroxylation
The Woodward cis-hydroxylation (also known as the Woodward reaction) is the chemical reaction of alkenes with iodine and silver acetate in wet acetic acid to form cis-diols. Woodward, R. B., (conversion of olefin into cis-diol) The reaction is named after its discoverer, Robert Burns Woodward. This reaction has found application in steroid synthesis. Reaction mechanism The reaction of the iodine with the alkene is promoted by the silver acetate, thus forming an iodinium ion (3). The iodinium ion is opened via SN2 reaction by acetic acid (or silver acetate) to give the first intermediate, the iodo-acetate (4). Through anchimeric assistance, the iodine is displaced via another SN2 reaction to give an oxonium ion (5), which is subsequently hydrolyzed to give the mono-ester (6). References See also * Prévost reaction The Prévost reaction is chemical reaction in which an alkene is converted by iodine and the silver salt of benzoic acid to a vicinal diol with anti stereoche ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ester
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides are fatty acid esters of glycerol; they are important in biology, being one of the main classes of lipids and comprising the bulk of animal fats and vegetable oils. Esters typically have a pleasant smell; those of low molecular weight are commonly used as fragrances and are found in essential oils and pheromones. They perform as high-grade solvents for a broad array of plastics, plasticizers, resins, and lacquers, and are one of the largest classes of synthetic lubricants on the commercial market. Polyesters are important plastics, with monomers linked by ester moieties. Phosphoesters form the backbone of DNA molecules. Nitrate esters, such as nitroglycerin, are known for their explosive properties. '' Nomenclature Etymology Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrolysis
Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis is the cleavage of biomolecules where a water molecule is consumed to effect the separation of a larger molecule into component parts. When a carbohydrate is broken into its component sugar molecules by hydrolysis (e.g., sucrose being broken down into glucose and fructose), this is recognized as saccharification. Hydrolysis reactions can be the reverse of a condensation reaction in which two molecules join into a larger one and eject a water molecule. Thus hydrolysis adds water to break down, whereas condensation builds up by removing water. Types Usually hydrolysis is a chemical process in which a molecule of water is added to a substance. Sometimes this addition causes both the substance and w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prevost Reaction Mechanism
Prevost, Prévost or Prévôt may refer to: Places * Prévost (electoral district), Quebec, a provincial electoral district * Prévost, Quebec, a community in the Laurentians region of Quebec, Canada ** Prévost station * Prevost, a community on Stuart Island, San Juan County, Washington, USA Ships * HMCS Prevost, a Canadian naval reserve unit in London, Ontario *, a 12-gun schooner that the Royal Navy purchased in 1803 and that the French privateer ''Austerlitz'' captured in 1807 * HMS ''Sir George Prevost'', a British naval warship * USS ''Lady Prevost'' (1812), a United States warship Other uses *Prevost Car, a bus manufacturer and division of Volvo Buses *Prévost reaction, a chemical reaction *Prevost's ground sparrow, a sparrow *Prevost's squirrel, a rodent People with the surname *Abbé Prévost (1697–1763), French novelist *André Prévost (composer) (1934–2001), Canadian composer *Augustine Prévost (1723–1786), British general * Charles Prévost (1899–1983), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxonium Ion
In chemistry, an oxonium ion is any cation containing an oxygen atom that has three bonds and 1+ formal charge. The simplest oxonium ion is the hydronium ion (). Alkyloxonium Hydronium is one of a series of oxonium ions with the formula R''n''H3−''n''O+. Oxygen is usually pyramidal with an sp3 hybridization. Those with ''n'' = 1 are called primary oxonium ions, an example being protonated alcohol (e.g. methanol). In acidic media, the oxonium functional group produced by protonating an alcohol can be a leaving group in the E2 elimination reaction. The product is an alkene. Extreme acidity, heat, and dehydrating conditions are usually required. Other hydrocarbon oxonium ions are formed by protonation or alkylation of alcohols or ethers (R−C−−R1R2). Secondary oxonium ions have the formula R2OH+, an example being protonated ethers. Tertiary oxonium ions have the formula R3O+, an example being trimethyloxonium. Tertiary alkyloxonium salts are useful alkylating a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anchimeric Assistance
In organic chemistry, neighbouring group participation (NGP, also known as anchimeric assistance) has been defined by the International Union of Pure and Applied Chemistry (IUPAC) as the interaction of a reaction centre with a lone pair of electrons in an atom or the electrons present in a pi bond contained within the parent molecule but not conjugated system, conjugated with the reaction centre. When NGP is in operation it is normal for the reaction rate to be increased. It is also possible for the stereochemistry of the reaction to be abnormal (or unexpected) when compared with a ''normal'' reaction. While it is possible for neighbouring groups to influence many reactions in organic chemistry (''e.g.'' the reaction of a diene such as 1,3-cyclohexadiene with maleic anhydride normally gives the endo isomer because of a secondary effect ) this page is limited to neighbouring group effects seen with carbocations and SN2 reaction, SN2 reactions. NGP by heteroatom lone pairs In this t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prevost Reaction Scheme
Prevost, Prévost or Prévôt may refer to: Places * Prévost (electoral district), Quebec, a provincial electoral district * Prévost, Quebec, a community in the Laurentians region of Quebec, Canada ** Prévost station * Prevost, a community on Stuart Island, San Juan County, Washington, USA Ships * HMCS Prevost, a Canadian naval reserve unit in London, Ontario *, a 12-gun schooner that the Royal Navy purchased in 1803 and that the French privateer ''Austerlitz'' captured in 1807 * HMS ''Sir George Prevost'', a British naval warship * USS ''Lady Prevost'' (1812), a United States warship Other uses *Prevost Car, a bus manufacturer and division of Volvo Buses *Prévost reaction, a chemical reaction *Prevost's ground sparrow, a sparrow *Prevost's squirrel, a rodent People with the surname *Abbé Prévost (1697–1763), French novelist *André Prévost (composer) (1934–2001), Canadian composer *Augustine Prévost (1723–1786), British general * Charles Prévost (1899–1983), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkene
In organic chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond. Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.H. Stephen Stoker (2015): General, Organic, and Biological Chemistry'. 1232 pages. Two general types of monoalkenes are distinguished: terminal and internal. Also called α-olefins, terminal alkenes are more useful. However, the International Union of Pure and Applied Chemistry (IUPAC) recommends using the name "alkene" only for acyclic hydrocarbons with just one double bond; alkadiene, alkatriene, etc., or polyene for acyclic hydrocarbons with two or more double bonds; cycloalkene, cycloalkadiene, etc. for cyclic ones; and "olefin" for the general class – cyclic or acyclic, with one or more double bonds. Acyclic alkenes, with only one double bond and no other functional groups (also known as mono-enes) form a homologous series of hydrocarbons with the general formula with '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
