Cyanosilylation Of Carbonyl Compounds Research Articles

Donor free stibenium cation as an efficient cyanosilylation catalyst.

The synthesis of novel stibenium cations and their catalytic application in cyanosilylation of carbonyl compounds have been described. Treatment of chlorostibine L1SbCl [L1 = 1,2-C6H4{N(CH2tBu)}2] (2) with 1 equiv. of AgOTf and AgSbF6 resulted in the formation of donor free L1SbOTf (3) and [L1Sb]+[SbF6]- (4), respectively. Among these three compounds, 4 exhibits excellent catalytic activity towards the cyanosilylation of aldehydes and ketones.

Nanoceria as a recyclable catalyst/support for the cyanosilylation of ketones and alcohol oxidation in cascade

The cyanosilylation of carbonyl compounds is a fundamental reaction in organic synthesis, to give cyanohydrins. Ketones are particularly reluctant to cyanosilane addition and require the action of a catalyst, and despite many soluble Brönsted and Lewis acids have been employed for this task, it is difficult to find in the open literature catalytic solids able to carry out the reaction. Here, we show that commercially available nanoceria catalyzes the cyanosilylation of different ketones (21 examples) at temperatures between 0 and 50 °C, in high yields, under solventless conditions if required. The nanoceria network atoms act in a cooperative way to provide a bifunctional acid-base solid catalyst for the cyanosilylation reaction. The amorphization of nanoceria during reaction, due to acid release, does not hamper the catalytic activity and, indeed, different types of nanoceria, even with supported metal nanoparticles on surface, are active for the reaction, enabling extensive reuses after air calcination and the use of the catalytic material for the aerobic oxidation of alcohols / cyanosilylation reaction.

Base Catalysis by Mono- and Polyoxometalates

In sharp contrast with acid-, photo-, and oxidation-catalysis by polyoxometalates, base catalysis by polyoxometalates has scarcely been investigated. The use of polyoxometalates as base catalysts have very recently received much attention and has been extensively investigated. Numerous mono- and polyoxometalate base catalyst systems effective for the chemical fixation of CO2, cyanosilylation of carbonyl compounds, and C–C bond forming reactions have been developed. Mono- and polyoxometalate base catalysts are classified into four main groups with respect to their structures: (a) monomeric metalates; (b) isopolyoxometalates; (c) heteropolyoxometalates; and (d) transition-metal-substituted polyoxometalates. This review article focuses on the relationship among the molecular structures, the basic properties, and the unique base catalysis of polyoxometalates on the basis of groups (a)–(d). In addition, reaction mechanisms including the specific activation of substrates and/or reagents such as the abstraction of protons, nucleophilic action toward substrates, and bifunctional action in combination with metal catalysts are comprehensively summarized.

Evans-Showell-type polyoxometalate constructing novel 3D inorganic architectures with alkaline earth metal linkers: syntheses, structures and catalytic properties.

Four new architectures containing [Co2Mo10H4O38]6- polyoxoanions, (C2N2H10)2[Sr(H2O)5][Co2Mo10H4O38]·2H2O 1, (C2N2H10)2[Ba(H2O)3][Co2Mo10H4O38]·3H2O 2, (C3N2H12)2[Sr(H2O)5][Co2Mo10H4O38]·3H2O 3 and (C3N2H12)[Ba(H2O)4][Ba(H2O)4][Co2Mo10H4O38]·2H2O 4 (C2N2H10 = ethylenediamine; C3N2H12 = 1,3-propanediamine) have been synthesized and characterized by elemental analysis, IR spectroscopy, solid diffuse reflective spectroscopy, TG analysis, powder X-ray diffraction and single crystal X-ray diffraction. Compounds 1 and 2 obtained in the presence of ethylenediamine, are made of Evans-Showell-type anions [Co2Mo10H4O38]6-, linked by Sr2+ or Ba2+ cations to form 3D frameworks. To our knowledge, compound 1(2) represents the first example of 3D architecture in which the Evans-Showell anions [Co2Mo10H4O38]6- were linked by pure alkaline earth cations. When propanediamine was used instead of ethylenediamine, compounds 3 and 4 with 2D networks were obtained. This phenomenon indicates that the organic cations, which adjust the reaction pH values, can induce different dimensional inorganic frameworks. As heterogeneous catalysts, compounds 1-4 show excellent catalytic performance in the cyanosilylation of carbonyl compounds. Furthermore, these catalytic reactions were performed under solvent-free conditions using only a low amount of the catalysts, and these catalysts can be recovered and reused without displaying any significant loss of activity. As far as we know, compounds 1-4 represent the first examples of cyanosilylation catalyzed by POM-based species containing alkaline earth metal cations.

A novel silver(i)-Keggin-polyoxometalate inorganic–organic hybrid: a Lewis acid catalyst for cyanosilylation reaction

A novel polyoxometalate (POM) hybrid material based on a Keggin polyanion and silver(I)–organic sheet, namely, [Ag4(apym)4(SiW12O40)]n (1), where apym = 2-aminopyrimidine, has been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, thermal gravimetric analysis, powder X-ray diffraction and single-crystal X-ray diffraction. In the structure of 1, polyanions link 2D 3-connected 4·82-fes AgI–organic sheets to generate a 3D complicated framework. Moreover, the catalytic performance of 1 towards the cyanosilylation of carbonyl compounds has been tested under mild conditions, showing a high turnover number and turnover frequency.

ChemInform Abstract: Efficient Synthesis of Cyanohydrin Trimethylsilyl Ethers via 1,2‐Chemoselective Cyanosilylation of Carbonyls.

AbstractThe cyanosilylation of carbonyl compounds (I) and (IV) using TmsCN (II) and triphenylphosphine supported on polystyrene as catalyst under solvent‐free conditions is described.

Strategic Design and Refinement of Lewis Acid–Base Catalysis by Rare-Earth-Metal-Containing Polyoxometalates

Efficient polyoxometalate (POM)-based Lewis acid-base catalysts of the rare-earth-metal-containing POMs (TBA(6)RE-POM, RE = Y(3+), Nd(3+), Eu(3+), Gd(3+), Tb(3+), or Dy(3+)) were designed and synthesized by reactions of TBA(4)H(4)[γ-SiW(10)O(36)] (TBA = tetra-n-butylammonium) with RE(acac)(3) (acac = acetylacetonato). TBA(6)RE-POM consisted of two silicotungstate units pillared by two rare-earth-metal cations. Nucleophilic oxygen-enriched surfaces of negatively charged POMs and the incorporated rare-earth-metal cations could work as Lewis bases and Lewis acids, respectively. Consequently, cyanosilylation of carbonyl compounds with trimethylsilyl cyanide ((TMS)CN) was efficiently promoted in the presence of the rare-earth-metal-containing POMs via the simultaneous activation of coupling partners on the same POM molecules. POMs with larger metal cations showed higher catalytic activities for cyanosilylation because of the higher activation ability of C═O bonds (higher Lewis acidities) and sterically less hindered Lewis acid sites. Among the POM catalysts examined, the neodymium-containing POM showed remarkable catalytic performance for cyanosilylation of various kinds of structurally diverse ketones and aldehydes, giving the corresponding cyanohydrin trimethylsilyl ethers in high yields (13 substrates, 94-99%). In particular, the turnover frequency (714,000 h(-1)) and the turnover number (23,800) for the cyanosilylation of n-hexanal were of the highest level among those of previously reported catalysts.

Cyanosilylation of Carbonyl Compounds with Trimethylsilyl Cyanide Catalyzed by an Yttrium‐Pillared Silicotungstate Dimer

Ein Yttrium-verbrücktes Silicowolframat-Dimer (siehe Bild) katalysiert die Cyanosilylierung von Ketonen und Aldehyden mit Trimethylsilylcyanid (TMSCN). Die Reaktionen verlaufen selektiv und geben die entsprechenden Cyanhydrintrimethylsilylether. Die katalytische Aktivität des Dimers ist vor allem für Aldehyde beeindruckend, mit einer Umsatzzahl von 18 000 und einer Umsatzfrequenz von 540 000 h−1 für n-Hexanal.

Cyanosilylation of Carbonyl Compounds with Trimethylsilyl Cyanide Catalyzed by an Yttrium‐Pillared Silicotungstate Dimer

Cyanosilylation of Carbonyl Compounds with Trimethylsilyl Cyanide Catalyzed by an Yttrium‐Pillared Silicotungstate Dimer

ChemInform Abstract: Polymer‐Supported, Carbon Dioxide‐Protected N‐Heterocyclic Carbenes: Synthesis and Application in Organo‐ and Organometallic Catalysis.

AbstractThe resin‐bond NHC‐based catalyst is prepared and used for a series of organocatalytic reactions such as cyanosilylation of carbonyl compounds as well as for trimerization reaction of isocyanates.

ChemInform Abstract: Metal and Solvent‐Free Cyanosilylation of Carbonyl Compounds with Tris(pentafluorophenyl)borane.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A Tin–Tungsten Mixed Oxide as an Efficient Heterogeneous Catalyst for CC Bond‐Forming Reactions

The tin-tungsten mixed oxide prepared by the calcination of the tin-tungsten hydroxide precursor with a Sn/W molar ratio of 2 at 800 degrees C (SnW2-800) acts as an effective and reusable solid catalyst for C-C bond-forming reactions, such as the cyclization of citronellal, the Diels-Alder reaction, and the cyanosilylation of carbonyl compounds with trimethylsilyl cyanide (TMSCN). Various kinds of structurally diverse aliphatic, aromatic, and unsaturated, heteroatom-containing substrates could be converted into the desired products in high to excellent yields. The observed catalyses for these reactions were truly heterogeneous and the recovered catalyst could be reused several times without an appreciable loss of its high catalytic performance. The Brønsted acid sites generated on the aggregated polytungstate species on SnW2-800 likely play an important role in the C-C bond-forming reactions.

Metal and solvent‐free cyanosilylation of carbonyl compounds with tris(pentafluorophenyl)borane

AbstractA highly effective method of the cynaosilylation of aldehydes and ketones with TMSCN in the presence of catalytic amount of B(C6F5)3 [tris(pentafluorophenyl)borane] has been developed. Cyano transfer from TMSCN to carbonyl group proceeds at room temperature under solvent‐free conditions. Various alehydes and ketones have been converted into the corresponding trimethylsilylether within short reaction times with excellent yield under mild conditions. Copyright © 2008 John Wiley & Sons, Ltd.

Inorganic/Organic Salts as Heterogeneous Basic Catalysts for Cyanosilylation of Carbonyl Compounds

The addition of TMSCN to carbonyl compounds catalyzed by K2CO3 as heterogeneous catalyst gave the corresponding cyanohydrin trimethylsilyl ethers from 20 minutes to 24 hours with 62% to 99% yields without solvent at room temperature. Moreover, it was found that chiral organic salts as heterogeneous catalysts also can catalyze the asymmetric version and afford the corresponding products with up to 99% yield and 12.4% ee.

ChemInform Abstract: Potassium Exchanged Zirconium Hydrogen Phosphate as Heterogeneous Catalyst in Cyanosilylation of Carbonyl Compounds.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Potassium Exchanged Zirconium Hydrogen Phosphate as Heterogeneous Catalyst in Cyanosilylation of Carbonyl Compounds

Potassium Exchanged Zirconium Hydrogen Phosphate as Heterogeneous Catalyst in Cyanosilylation of Carbonyl Compounds

ChemInform Abstract: Solid Acid and Base‐Catalyzed Cyanosilylation of Carbonyl Compounds with Cyanotrimethylsilane.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.