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Paul Knochel (born 15 November 1955) is a French chemist and a member of the French Academy of Sciences.
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Paul Knochel (born 15 November 1955) is a French chemist and a member of the French Academy of Sciences.
Paul Knochel was born in Strasbourg. He studied chemistry at the IUT (Institut Universitaire de Technologie) in Strasbourg, then at the ENSCS (École Nationale Supérieure de Chimie de Strasbourg). From 1979 to 1982, he completed his thesis entitled "Nitroallyl-halogenide und -ester als effiziente Verknüpfungsreagenzien" at ETH (Eidgenössische Technische Hochschule) Zurich (Switzerland) in Prof. Dieter Seebach's group. He then spent 4 years at the CNRS (Centre National de la Recherche Scientifique) at the Pierre et Marie Curie University in Paris in the group of Prof. Jean-François Normant. During this period, he studied carbozincation reactions using allylic reagents and prepared bimetallic compounds bearing two different metals (Lithium, Magnesium or Zinc) on the same carbon atom. He then joined Prof. Martin F. Semmelhack's laboratory for a post-doctoral fellowship during which he worked on the use of indoles-chromium complexes in organic synthesis. In 1987, he accepted a position as Assistant Professor in the Department of Chemistry at the University of Michigan at Ann Arbor (MI, USA) where he developed the first methods for the preparation of polyfunctional organometallic zinc species. In 1991, he was promoted to Professor at the same University before moving to Marburg (Germany) in 1992, where he was offered a position as Professor of Organic Chemistry in the Department of Chemistry at the Philips-Universität University. He continued his work on the chemistry of polyfunctional organozinciques and their use in asymmetric synthesis. In 1999, he was offered a position as Professor of Organic Chemistry at the University of Munich (Ludwig-Maximilians-Universität – LMU) [1] [2] which he still holds in 2019. He has developed new methods for the preparation of polyfunctional organometallic species as well as numerous synthetic methods using organometallic reagents or catalysts.
Knochel has developed a series of new methods for the preparation of polyfunctional organometallic species of zinc [3] and magnesium, but also many other metals such as copper, aluminium, [4] manganese, indium, iron, lanthanum and samarium. In addition, he highlighted the fact that lithium salts catalyse a significant number of organometallic reactions, including the oxidative addition of a metal such as magnesium, [5] zinc, [6] indium, manganese or aluminium to an organic halide. It has shown that the use of lithium derivatives (chloride, acetylacetonates or alcoholates) [7] [8] catalyses the halogen-metal exchange in the preparation of organomagnesians [8] and organozinciques. In addition, it has synthesized a series of new cluttered metal bases derived from tetramethylpiperidine allowing C-H activations of aromatic and heterocyclic unsaturated systems. [9] [10] He has also conducted research on a series of diastereoselective mixed coupling reactions catalyzed by palladium, iron, cobalt [11] and chromium. He has succeeded in considerably increasing the scope of these organic synthesis reactions through continuous flow chemistry. [12] [13] [14] [15] [16] [17] It has also implemented a synthetic methodology for the preparation of lithians, [18] [19] [20] zinciques and organocuprates with high enantioselectivity and has demonstrated the usefulness of this method for preparing pheromones [18] containing up to five chiral centres. By using additives such as zinc or magnesium pivalate, it has been possible to prepare organozinciques with high stability against air and moisture. [15] [21]
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The Sandmeyer reaction is a chemical reaction used to synthesize aryl halides from aryl diazonium salts using copper salts as reagents or catalysts. It is an example of a radical-nucleophilic aromatic substitution. The Sandmeyer reaction provides a method through which one can perform unique transformations on benzene, such as halogenation, cyanation, trifluoromethylation, and hydroxylation.
The Negishi coupling is a widely employed transition metal catalyzed cross-coupling reaction. The reaction couples organic halides or triflates with organozinc compounds, forming carbon-carbon bonds (C-C) in the process. A palladium (0) species is generally utilized as the metal catalyst, though nickel is sometimes used. A variety of nickel catalysts in either Ni0 or NiII oxidation state can be employed in Negishi cross couplings such as Ni(PPh3)4, Ni(acac)2, Ni(COD)2 etc.
Organozinc chemistry is the study of the physical properties, synthesis, and reactions of organozinc compounds, which are organometallic compounds that contain carbon (C) to zinc (Zn) chemical bonds.
Group 2 organometallic chemistry refers to the chemistry of compounds containing carbon bonded to any group 2 element. By far the most common group 2 organometallic compounds are the magnesium-containing Grignard reagents which are widely used in organic chemistry. Other organmetallic group 2 compounds are rare and are typically limited to academic interests.
A frustrated Lewis pair (FLP) is a compound or mixture containing a Lewis acid and a Lewis base that, because of steric hindrance, cannot combine to form a classical adduct. Many kinds of FLPs have been devised, and many simple substrates exhibit activation.
Alexander C. Filippou has been a Professor of Inorganic Chemistry at the Rheinische-Friedrich-Wilhelms-University Bonn since 2005.
Organocerium chemistry is the science of organometallic compounds that contain one or more chemical bond between carbon and cerium. These compounds comprise a subset of the organolanthanides. Most organocerium compounds feature Ce(III) but some Ce(IV) derivatives are known.
Ulrich "Uli" Kortz is a German chemist and professor, working in the area of synthetic polyoxometalate chemistry.
Corinna S. Schindler is a Professor of Chemistry at the University of Michigan. She develops catalytic reactions with environmentally benign metals such as iron, towards the synthesis of biologically active small molecules. For her research in the development of new catalysts, Schindler has been honored with several early-career researcher awards including the David and Lucile Packard Foundation Fellowship in 2016, the Alfred P. Sloan Fellowship in 2017, and being named a member of the C&EN Talented 12 in 2017. Schindler has served on the Editorial Board of Organic and Bimolecular Chemistry since 2018.
Zirconocene is a hypothetical compound with 14 valence electrons, which has not been observed or isolated. It is an organometallic compound consisting of two cyclopentadienyl rings bound on a central zirconium atom. A crucial question in research is what kind of ligands can be used to stabilize the Cp2ZrII metallocene fragment to make it available for further reactions in organic synthesis.
Rosenthal's reagent is a metallocene bis(trimethylsilyl)acetylene complex with zirconium (Cp2Zr) or titanium (Cp2Ti) used as central atom of the metallocene fragment Cp2M. Additional ligands such as pyridine or THF are commonly used as well. With zirconium as central atom and pyridine as ligand, a dark purple to black solid with a melting point of 125–126 °C is obtained. Synthesizing Rosenthal's reagent of a titanocene source yields golden-yellow crystals of the titanocene bis(trimethylsilyl)acetylene complex with a melting point of 81–82 °C. This reagent enables the generation of the themselves unstable titanocene and zirconocene under mild conditions.
Sukbok Chang is a South Korean organic chemist. He is a distinguished professor in the Department of Chemistry at Korea Advanced Institute of Science and Technology (KAIST). He is also the director of the Institute for Basic Science (IBS) Center for Catalytic Hydrocarbon Functionalizations (CCHF). He was an associate editor on ACS Catalysis and has served on the editorial advisory boards of The Journal of Organic Chemistry, Journal of the American Chemical Society, and Accounts of Chemical Research. His major research interest is transition metal catalyzed C-H bond functionalization for the carbon-carbon bond and carbon-heteroatom bond formation.
Helma B. Wennemers is a German organic chemist. She is a professor of organic chemistry at the Swiss Federal Institute of Technology in Zurich.
2-Methyldodecane, an organic compound with a chemical formula C13H28, is an isomer of tridecane. It is produced by the reaction of 1-bromodecane and diisopropyl zinc. Reaction of decylmagnesium bromide and 2-bromopropane produce 2-methyldodecane too. Another method to produce 2-methyldodecane is react 1-dodecene and trimethylaluminium.
The borosulfates are heteropoly anion compounds which have sulfate groups attached to boron atoms. Other possible terms are sulfatoborates or boron-sulfur oxides. The ratio of sulfate to borate reflects the degree of condensation. With [B(SO4)4]5- there is no condensation, each ion stands alone. In [B(SO4)3]3- the anions are linked into a chain, a chain of loops, or as [B2(SO4)6]6− in a cycle. Finally in [B(SO4)2]− the sulfate and borate tetrahedra are all linked into a two or three-dimensional network. These arrangements of oxygen around boron and sulfur can have forms resembling silicates. The first borosulfate to be discovered was K5[B(SO4)4] in 2012. Over 75 unique compounds are known.
In organometallic chemistry, metal–halogen exchange is a fundamental reaction that converts an organic halide into an organometallic product. The reaction commonly involves the use of electropositive metals and organochlorides, bromides, and iodides. Particularly well-developed is the use of metal–halogen exchange for the preparation of organolithium compounds.
Jieping Zhu is an organic chemist specializing in natural product total synthesis and organometallics. He is a professor of chemistry at EPFL and the head of the Laboratory of Synthesis and Natural Products.
Organonickel(IV) complex are organonickel compounds that feature nickel in the +4 oxidation state. These high-valent nickel compounds are intermediates or models thereof for various catalytic reactions.
A magnesium(I) dimer is a molecular compound containing a magnesium to magnesium bond (Mg-Mg), giving the metal an apparent +1 oxidation state. Alkaline earth metals are commonly found in the +2-oxidation state, such as magnesium. The M2+ are considered as redox-inert, meaning that the +2 state is significant. However, recent advancements in main group chemistry have yielded low-valent magnesium (I) dimers, also given as Mg (I), with the first compound being reported in 2007. They can be generally represented as LMg-MgL, with L being a monoanionic ligand. For example, β-diketiminate, commonly referred to as Nacnac, is a useful chelate regarding these complexes. By tuning the ligand, the thermodynamics of the complex change. For instance, the ability to add substituents onto Nacnac can contribute to the steric bulk, which can affect reactivity and stability. As their discovery has grown, so has their usefulness. They are employed in organic and inorganic reduction reactions. It is soluble in a hydrocarbon solvent, like toluene, stoichiometric, selective, and safe.
René Peters is a German chemist and since 2008 Professor of Organic Chemistry at the University of Stuttgart.
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