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Roskamp Reaction
In organic chemistry, the Roskamp reaction is a name reaction describing the reaction between α-diazoesters (such as ethyl diazoacetate) and aldehydes to form β-ketoesters, often utilizing various Lewis acids (such as boron trifluoride, BF3, stannous chloride, SnCl2, and Germanium dichloride, GeCl2) as catalysts. The reaction is notable for its mild reaction conditions and selectivity. Background The Roskamp reaction was published seminally in 1989 by Roskamp and co-workers. The authors initially proposed that the reaction would convert aldehydes to alkenes via a pseudo-Wittig reaction, Wittig type reaction; however, β-ketoesters were the only products to be observed. The authors also noted that aliphatic aldehyde gave higher yield than aromatic aldehydes due to enolization. Additionally, the mild reaction conditions shows advantages in preventing side reactions and increasing functional group tolerance. In 1992, Roskamp and co-workers expanded the scope of diazoacetate to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Chemistry
Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, J.; Greeves, N. and Warren, S. (2012) ''Organic Chemistry''. Oxford University Press. pp. 1–15. . Study of structure determines their structural formula. Study of properties includes physical and chemical properties, and evaluation of chemical reactivity to understand their behavior. The study of organic reactions includes the chemical synthesis of natural products, drugs, and polymers, and study of individual organic molecules in the laboratory and via theoretical ( in silico) study. The range of chemicals studied in organic chemistry includes hydrocarbons (compounds containing only carbon and hydrogen) as well as compounds based on carbon, but also containing other elements, especially oxygen, nitrogen, sulfur, phosphorus (included in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olefins
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 ''n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meerwein Arylation
The Meerwein arylation is an organic reaction involving the addition of an aryl diazonium salt (ArN2X) to an electron-poor alkene usually supported by a metal salt. The reaction product is an alkylated arene compound. The reaction is named after Hans Meerwein, one of its inventors who first published it in 1939. An electron-withdrawing group (EWG) on the alkene makes it electron deficient and although the reaction mechanism is unclear, involvement of an aryl radical is presumed after loss of nitrogen in the diazonium salt followed by a free radical addition. In the primary reaction product the intermediate alkyl radical is then captured by the diazonium counterion X which is usually a halogen or a tetrafluoroborate. In a subsequent step an elimination reaction liberates HX (for instance hydrochloric acid) and an aryl vinyl compound is formed. The reaction mechanism from the arene's view ranks as a radical-nucleophilic aromatic substitution. In a general scope a Meerwein ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Büchner–Curtius–Schlotterbeck Reaction
The Buchner–Curtius–Schlotterbeck reaction is the Chemical reaction, reaction of aldehydes or ketones with aliphatic diazoalkanes to form homologated ketones. It was first described by Eduard Buchner and Theodor Curtius in 1885 and later by Fritz Schlotterbeck in 1907. Two German chemists also preceded Schlotterbeck in discovery of the reaction, Hans von Pechmann in 1895 and Viktor Meyer in 1905. The reaction has since been extended to the synthesis of β-keto esters from the condensation between aldehydes and diazo esters. The general reaction scheme is as follows: The reaction yields two possible carbonyl compounds (I and II) along with an epoxide (III). The ratio of the products is determined by the reactant used and the reaction conditions. Reaction Mechanism The general mechanism is shown below. The resonating arrow (1) shows a Resonance (chemistry), resonance contributor of the diazo compound with a lone pair of electrons on the carbon adjacent to the nitrogen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
