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Showing papers in "ChemInform in 1981"


Journal ArticleDOI
Abstract: Addition of acetonitrile to the traditional CCl4/H2O solvent system for ruthenium tetraoxide catalyzed oxidations leads to a greatly improved system; some applications to olefins, alcohols, aromatic rings, and ethers are described. © 1981, American Chemical Society. All rights reserved.

1,140 citations





Journal ArticleDOI
TL;DR: In this paper, a detailed molecular orbital analysis points to the crucial role of olefin slipping, a deformation to q1 coordination, in activating the OLEF complexes, and the similarities and differences of the activation process in d2 Cp2WRt, d6 Fe(C0):' and CPF~(CO)~', d8 PtL, and Fe(c0)4, and dIo Ni(PR3)2 olefins are the subject of the study.
Abstract: On theoretical grounds a symmetrically q2 coordinated olefin is deactivated toward attack by an external nucleophile. A detailed molecular orbital analysis points to the crucial role of olefin slipping, a deformation to q1 coordination, in activating the olefin. The similarities and differences of the activation process in d2 Cp2WRt, d6 Fe(C0):' and CPF~(CO)~', d8 PtL, and Fe(C0)4, and dIo Ni(PR3)2 olefin complexes are the subject of this study.

164 citations





Book ChapterDOI
TL;DR: A suitable approach is the planning and synthesis of arrangements of various types of molecules, which are all constructed such that they fit into one another and thus by themselves and in an organized way build up to functional systems where the functional groups are held fast in the desired arrangement by the intermolecular forces.
Abstract: Definite complexes between various uncharged molecules are still relatively unexplored 1) although this type of complexation plays a fundamental role in biochemical processes, eg the base-pairing of nucleic acids 2), enzyme/substrate or pharmacon/receptor interactions “The molecular biology is a striking example of the fact that molecules which fit into one another sterically and functionally, lead together to fundamentally new functional possibilities” 1d) A suitable approach in this respect is “the planning and synthesis of arrangements of various types of molecules, which are all constructed such that they fit into one another and thus by themselves and in an organized way build up to functional systems where the functional groups are held fast in the desired arrangement by the intermolecular forces” 1d)

102 citations



Journal ArticleDOI
TL;DR: Aus dem Dihydropyran-diol-benzaldehydacetal (Ia) erhalt man in der angegebenen Weise den als Schlusselverbindung wichtigen exocyclischen Enolether (VII) and aus ihm das Prelog-Djerassi-Lacton (VIIIb), welches Interesse bei der Synthese von Macrolid-Antibiotica besitzt as mentioned in this paper.
Abstract: Aus dem Dihydropyran-diol-benzaldehydacetal (Ia) erhalt man in der angegebenen Weise den als Schlusselverbindung wichtigen exocyclischen Enolether (VII) und aus ihm das Prelog-Djerassi-Lacton (VIIIb), welches Interesse bei der Synthese von Macrolid-Antibiotica besitzt.





Journal ArticleDOI
TL;DR: In this article, the Elektronentransfer von Me2COH-Radikalen (durch γ-bestrahlung einer Aceton + Propanol-(2)-haltigen Losung) auf kolloidale Ag-Teilchen and the Reduktion von H2O durch die an den Ag-teilchen gespeicherten ElektRONen werden mit Hilfe konduktometrischer Methoden untersucht.
Abstract: Der Elektronentransfer von Me2COH-Radikalen (durch γ-Bestrahlung einer Aceton + Propanol-(2)-haltigen Losung) auf kolloidale Ag-Teilchen und die Reduktion von H2O durch die an den Ag-Teilchen gespeicherten Elektronen werden mit Hilfe konduktometrischer Methoden untersucht.

Journal ArticleDOI
TL;DR: Trimethylsilyldiazomethane (TMSCHN2) was used in the Arndt-Eistert synthesis and homologation of carbonyl compounds as discussed by the authors.
Abstract: Trimethylsilyldiazomethane (TMSCHN2), known as a stable and safe substitute for highly toxic and explosive diazomethane in the Arndt-Eistert synthesis and homologation of carbonyl compounds, has smoothly reacted with various carboxylic acids in methanolic benzene solution to give the corresponding methyl esters in excellent yields.

Journal ArticleDOI
TL;DR: In this article, a Pt-Partikel of 32-A-Diameter in wasriger Losung erzeugt is erzeugen, by Citrat-Reduktion von Hexachloroplatinat.
Abstract: Durch Citrat-Reduktion von Hexachloroplatinat werden Pt-Partikel von 32-A-Diameter in wasriger Losung erzeugt.

Book ChapterDOI
TL;DR: In this article, the chemistry of 1,2- and 1,3-dithiole compounds has developed considerably for several reasons, such as the discovery of bis(l,3dithiol-2-ylidene), often called tetrathiafulvalene, and its derivatives are important components of organic metals.
Abstract: Publisher Summary In the last 12 years, the chemistry of 1,2- and 1,3-dithiole compounds has developed considerably for several reasons. One reason is that bis(l,3-dithiol-2-ylidene), often called tetrathiafulvalene, and its derivatives are important components of organic metals. Another is that the discovery of 1,6,6aλ 4 -trithiapentalenes has brought attention to their partial bonding with quasi-covalent bonds whose bonding character, in terms of “usual” covalent bonds, is between zero and unity. In these fields, dithiolium cations are useful synthetic intermediates. Most known neutral dithiole derivatives are written as polar compounds, and these dipolar formulas give a correct picture of some properties of these compounds. The typical examples cited are the 1,2-dithiole-3-thiones and 1,6,6aλ 4 -trithiapentalenes. The chapter discusses the preparation of the 1,2- and 1,3-Dithiolium ions with the formation of the 1,2-Dithiole Ring and from 1,2-Dithiole Derivatives. Chemical properties are discussed wherein general remarks, hydrogen exchange, reduction, and attack by oxygen nucleophiles, sulfur or selenium nucleophiles, nitrogen nucleophiles, carbon nucleophiles, and electrophilic attack are also discussed. The chapter also discusses their physical properties that include quantum mechanical calculation, molecular structure, electronic absorption spectra, NMR (nuclear magnetic resonance), ESR, and ESCA data, conductivity, and mass spectra.

Book ChapterDOI
TL;DR: In this article, the authors discuss stoichiometric organic reactions, catalytic organic reactions and organometallic synthesis using phase-transfer catalysis, and discuss the use of halides with quaternary ammonium halides functioning as catalysts.
Abstract: Publisher Summary This chapter discusses stoichiometric organic reactions, catalytic organic reactions, and organometallic synthesis. One of the major developments in organic chemistry during the past 15 years has been the application of phase-transfer catalysis to synthesis. As a basis for discussing the concept of the liquid–liquid phase-transfer process, nucleophilic substitution reactions of halides with quaternary ammonium halides functioning as catalysts are considered in the chapter. The first experiments that were carried out in the author's laboratory on organometallic phase-transfer catalysis were concerned with the reduction of nitrobenzenes to anilines by triiron dodecacarbonyl. The reaction of halides with iron pentacarbonyl, base, and tetrabutylammonium bromide as the catalyst has been reported to give ketones and variable amounts of hydrocarbons. One of the most important metal carbonyl anions, as far as catalytic processes are concerned, is the cobalt tetracarbonyl anion, Co(CO)4−. The chapter describes crown ether-catalyzed generation of the Co(CO)4− ion in ether or hydrocarbon solvents. The carbonylation of halides to carboxylic acids, catalyzed by Co2(CO)8, is a transformation of genuine synthetic utility. Even certain phase-transfer catalysts can be carbonylated to carboxylic acids by acetylcobalt tetracarbonyl. Alcohols can be dehydrogenated to carbonyl compounds by exposure to a catalytic amount of a rhodium complex under phase-transfer conditions. The formation of dihalocarbene is one of the most useful phase-transfer processes developed in organic chemistry. Chromium tricarbonyl complexes of arylacetic esters can be alkylated by the use of phase-transfer catalysis or sodium hydride in N,N-dimethylformamide.







Book ChapterDOI
Klaus Jonas1
TL;DR: In this article, the reduction equivalents required for the conversion of N 2 to NH 3 are obtained from the carbanionic phenyl groups bonded to nickel, which is supported by results obtained by means of reactions of nickel complexes 1−3 with more polar organometallics than AIR 3 −that is, with organo-alkali metal compounds.
Abstract: Publisher Summary This chapter discusses alkali metal organyl-, alkali metal hydrido-, and alkali metal diorganylphosphidonickel(0) π -ligand complexes; dilithium–nickel–olefin complexes; and transition metal–olefin and alkali metal–transition metal–olefin complexes from metallocenes by reductive C 5 H 5 elimination. In spite of the many important developments resulting from the nickel effect, little attention has been paid to its mechanism, which is at present considered to consist of an insertion step and a displacement step. This basic concept of the nickel effect is supported by results obtained in the chapter by means of reactions of nickel complexes 1–3 with more polar organometallics than AIR 3 ––that is, with organo–alkali metal compounds. The reduction equivalents required for the conversion of N 2 to NH 3 are obtained from the carbanionic phenyl groups bonded to nickel. In general, high reaction temperatures are necessary for the synthesis of alkali metal hydrides from the elements, although sodium hydride can also be formed at room temperature if both naphthalene and titanium isopropoxide are present.


Journal ArticleDOI
TL;DR: In this paper, Ni(II)-Komplexe von Tetraazama-krocyclen erleiden eine Einelektronenreduktion, wobei Komplexe mit konjugierten α-Diimineinheiten zu Spezies with an ein Ligandradikal komplexiertes Ni (II) wie (I)-(IV) fuhren.
Abstract: Einkernige Ni(II)-Komplexe von Tetraazama- krocyclen erleiden eine Einelektronenreduktion, wobei Komplexe mit konjugierten α-Diimineinheiten zu Spezies mit an ein Ligandradikal komplexiertes Ni(II) wie (I)-(IV) fuhren ,wahrend Komplexe mit nichtkonjugierten α-Diiminen die Ni(I)- Spezies (V)-(VIII) bilden.

Journal ArticleDOI
TL;DR: Aus dem Azepino-indol (I) erhalt man mit den Aldehyden (II) die stereoisomeren Kondensate (III) und (IV), die zu (V, X, Y) alkyliert werden konnen as mentioned in this paper.
Abstract: Aus dem Azepino-indol (I) erhalt man mit den Aldehyden (II) die stereoisomeren Kondensate (III) und (IV), die zu (V) und (VI) alkyliert werden konnen.