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Oxo-Diels–Alder Reaction
An oxo-Diels–Alder reaction (also called an oxa-Diels–Alder reaction) is an organic reaction and a variation of the Diels–Alder reaction in which a suitable diene reacts with an aldehyde to form a dihydropyran ring. This reaction is of some importance to synthetic organic chemistry. : The oxo-DA reaction was first reported in 1949 using a 2-methylpenta-1,3-diene and formaldehyde as reactants. : Asymmetric oxo-DA reactions (including catalytic reactions) are well known.''Tetrahedron Report number 869 Asymmetric hetero-Diels–Alder reactions of carbonyl compounds'' Helene Pellissier Tetrahedron In geometry, a tetrahedron (: tetrahedra or tetrahedrons), also known as a triangular pyramid, is a polyhedron composed of four triangular Face (geometry), faces, six straight Edge (geometry), edges, and four vertex (geometry), vertices. The tet ... 65 (2009) 2839–2877 Many strategies rely on coordinating a chiral Lewis acid to the carbonyl group. See also * Aza-Diels–Al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otto Diels
Otto Paul Hermann Diels (; 23 January 1876 – 7 March 1954) was a German chemist. His most notable work was done with Kurt Alder on the Diels–Alder reaction, a method for cyclohexene synthesis. The pair was awarded the Nobel Prize in Chemistry in 1950 for their work. Their method of synthesizing cyclic organic compounds proved valuable for the manufacture of synthetic rubber and plastic. He completed his education at the University of Berlin, where he later worked. Diels was employed at the University of Kiel when he completed his Nobel Prize-winning work, and remained there until he retired in 1945. Diels was married, with five children. He died in 1954. Early life Diels was born on 23 January 1876 in Hamburg, Germany, and moved with his family to Berlin when he was two years old. He studied in Berlin at Joachimsthalsches Gymnasium before attending the University of Berlin starting in 1895. While at university, Diels studied chemistry under Emil Fischer, eventu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kurt Alder
Kurt Alder (; 10 July 1902 – 20 June 1958) was a German chemist and Nobel laureate. Biography Alder was born in the industrial area of Königshütte, Silesia (modern day Chorzów, Upper Silesia, Poland), where he received his early schooling. Alder left the area when Königshütte became part of Poland in 1922. He studied chemistry at the University of Berlin from 1922, and later at the University of Kiel where his PhD was awarded in 1926 for work supervised by Otto Paul Hermann Diels. In 1930 Alder was appointed reader for chemistry at Kiel, and promoted to lecturer in 1934. In 1936 he left Kiel to join I G Farben Industrie at Leverkusen, where he worked on synthetic rubber. Then in 1940 he was appointed Professor of Experimental Chemistry and Chemical Technology at the University of Cologne and Director of the Institute of Chemistry there. Throughout this time and despite the many obstacles to original research in Europe at the time, he continued a systematic progra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Reaction
Organic reactions are chemical reactions involving organic compounds. The basic organic chemistry reaction types are addition reactions, elimination reactions, substitution reactions, pericyclic reactions, rearrangement reactions, mechanistic organic photochemistry, photochemical reactions and organic redox reaction, redox reactions. In organic synthesis, organic reactions are used in the construction of new organic molecules. The production of many man-made chemicals such as drugs, plastics, food additives, fabrics depend on organic reactions. The oldest organic reactions are combustion of organic fuels and saponification of fats to make soap. Modern organic chemistry starts with the Wöhler synthesis in 1828. In the history of the Nobel Prize in Chemistry awards have been given for the invention of specific organic reactions such as the Grignard reaction in 1912, the Diels–Alder reaction in 1950, the Wittig reaction in 1979 and olefin metathesis in 2005. Classifications Organ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diels–Alder Reaction
In organic chemistry, the Diels–Alder reaction is a chemical reaction between a Conjugated system, conjugated diene and a substituted alkene, commonly termed the Diels–Alder reaction#The dienophile, dienophile, to form a substituted cyclohexene derivative. It is the prototypical example of a pericyclic reaction with a concerted reaction, concerted mechanism. More specifically, it is classified as a thermally allowed [4+2] cycloaddition with Woodward–Hoffmann rules, Woodward–Hoffmann symbol [π4s + π2s]. It was first described by Otto Diels and Kurt Alder in 1928. For the discovery of this reaction, they were awarded the Nobel Prize in Chemistry in 1950. Through the simultaneous construction of two new carbon–carbon bonds, the Diels–Alder reaction provides a reliable way to form six-membered rings with good control over the regio- and stereochemical outcomes. Consequently, it has served as a powerful and widely applied tool for the introduction of chemical complexity in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diene
In organic chemistry, a diene ( ); also diolefin, ) or alkadiene) is a covalent compound that contains two double bonds, usually among carbon atoms. They thus contain two alk''ene'' units, with the standard prefix ''di'' of systematic nomenclature. As a subunit of more complex molecules, dienes occur in naturally occurring and synthetic chemicals and are used in organic synthesis. Conjugated dienes are widely used as monomers in the polymer industry. Polyunsaturated fats are of interest to nutrition. Classes Dienes can be divided into three classes, depending on the relative location of the double bonds: #Cumulated dienes have the double bonds sharing a common atom. The result is more specifically called an allene. #Conjugated dienes have conjugated double bonds separated by one single bond. Conjugated dienes are more stable than other dienes because of resonance. #Unconjugated dienes have the double bonds separated by two or more single bonds. They are usually less ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aldehyde
In organic chemistry, an aldehyde () (lat. ''al''cohol ''dehyd''rogenatum, dehydrogenated alcohol) is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl group. Aldehydes are a common motif in many chemicals important in technology and biology. Structure and bonding Aldehyde molecules have a central carbon atom that is connected by a double bond to oxygen, a single bond to hydrogen and another single bond to a third substituent, which is carbon or, in the case of formaldehyde, hydrogen. The central carbon is often described as being sp2- hybridized. The aldehyde group is somewhat polar. The bond length is about 120–122 picometers. Physical properties and characterization Aldehydes have properties that are diverse and that depend on the remainder of the molecule. Smaller aldehydes such as formaldehyde and acetaldehyde are solubl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dihydropyran
In organic chemistry, dihydropyran refers to two heterocyclic compounds with the formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwe ... C5H8O: * 3,4-Dihydro-2''H''-pyran *3,6-dihydro-2''H''-pyran Nomenclature In IUPAC names, "dihydro" refers to the two added hydrogen atoms needed to remove one double bond from the parent compound pyran. The numbers in front of the prefix indicate the position of the added hydrogen atoms (and not the position of the double bonds). The italicized capital ''H'' denotes the "indicated hydrogen", which is a second hydrogen atom present on the location where no double bond is present.A Guide to IUPAC Nomenclature of Organic Compounds (Recommendations 1993)''R-1.3 Indicated Hydrogen''/ref> See also * Pyran * Tetrahydropyran References {{DEFAUL ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formaldehyde
Formaldehyde ( , ) (systematic name methanal) is an organic compound with the chemical formula and structure , more precisely . The compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde. It is stored as aqueous solutions (formalin), which consists mainly of the hydrate CH2(OH)2. It is the simplest of the aldehydes (). As a precursor to many other materials and chemical compounds, in 2006 the global production of formaldehyde was estimated at 12 million tons per year. It is mainly used in the production of industrial resins, e.g., for particle board and coatings. Formaldehyde also occurs naturally. It is derived from the degradation of serine, dimethylglycine, and lipids. Demethylases act by converting N-methyl groups to formaldehyde. Formaldehyde is classified as a group 1 carcinogen and can cause respiratory and skin irritation upon exposure. Forms Formaldehyde is more complicated than many simple carbon compounds in that i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asymmetric Synthesis
Enantioselective synthesis, also called asymmetric synthesis, is a form of chemical synthesis. It is defined by IUPAC as "a chemical reaction (or reaction sequence) in which one or more new elements of chirality are formed in a substrate molecule and which produces the stereoisomeric (enantiomeric or diastereomeric) products in unequal amounts." Put more simply: it is the synthesis of a compound by a method that favors the formation of a specific enantiomer or diastereomer. Enantiomers are stereoisomers that have opposite configurations at every chiral center. Diastereomers are stereoisomers that differ at one or more chiral centers. Enantioselective synthesis is a key process in modern chemistry and is particularly important in the field of pharmaceuticals, as the different enantiomers or diastereomers of a molecule often have different biological activity. Overview Many of the building blocks of biological systems such as sugars and amino acids are produced exclusively as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrahedron (journal)
''Tetrahedron'' is a weekly peer-reviewed scientific journal covering the field of organic chemistry. According to the ''Journal Citation Reports'', ''Tetrahedron'' has a 2020 impact factor of 2.1. ''Tetrahedron'' and Elsevier, its publisher, support an annual symposium. In 2010, complaints were raised over its high subscription cost. Notable papers , the Web of Science lists ten papers from ''Tetrahedron'' that have more than 1000 citations. The four articles that have been cited more than 2000 times are: * – cited 2228 times * – cited 2162 times * – cited 2124 times * – cited 2107 times See also * ''Tetrahedron Letters'' * '' Tetrahedron Computer Methodology'' * ''Polyhedron In geometry, a polyhedron (: polyhedra or polyhedrons; ) is a three-dimensional figure with flat polygonal Face (geometry), faces, straight Edge (geometry), edges and sharp corners or Vertex (geometry), vertices. The term "polyhedron" may refer ...'' (journal) Reference ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
