2611-00-9Relevant articles and documents
Rethinking the Claisen–Tishchenko Reaction
Morris, Stacey A.,Gusev, Dmitry G.
supporting information, p. 6228 - 6231 (2017/05/19)
Pincer-type complexes [OsH2(CO){PyCH2NHCH2CH2NHPtBu2}] and [OsH2(CO){HN(CH2CH2PiPr2)2}] catalyze the disproportionation reaction of aldehydes via an outer-sphere bifunctional mechanism achieving turnover frequencies up to 14 000 h?1. The N?H group of the catalysts is a key player in this process, elucidated with the help of DFT calculations.
An environmentally benign solvent-free Tishchenko reaction
Waddell, Daniel C.,Mack, James
body text, p. 79 - 82 (2010/04/22)
Herein, we describe the solvent-free ball milling Tishchenko reaction. Using high speed ball milling and a sodium hydride catalyst, the Tishchenko reaction was performed for aryl aldehydes in high yields in 0.5 hours. The reaction is not affected by the type of ball bearing used and can be successful when conducted in a liquid nitrogen environment.
Iridium-catalyzed oxidative dimerization of primary alcohols to esters using 2-butanone as an oxidant
Suzuki, Takeyuki,Matsuo, Tomohito,Watanabe, Kazuhiro,Katoh, Tadashi
, p. 1453 - 1455 (2007/10/03)
Oxidative dimerization of primary alcohols with 2-butanone in the presence of an amino alcohol-based Ir bifunctional catalyst was accomplished for the first time. The reaction proceeds with 1-2 mol% of the catalyst and 0.3 mol equivalents of K2CO3 in 2-butanone at room temperature to give the corresponding dimeric esters in 30-93% yield. Georg Thieme Verlag Stuttgart.
Tishchenko reaction using an iridium-ligand bifunctional catalyst
Suzuki, Takeyuki,Yamada, Taichiro,Matsuo, Tomohito,Watanabe, Kazuhiro,Katoh, Tadashi
, p. 1450 - 1452 (2007/10/03)
Tishchenko reaction of aldehydes in the presence of an amino alcohol-based Ir bifunctional catalyst was developed. The reaction proceeds with 1 mol% of the catalyst and 20-30 mol% of K2CO3 in acetonitrile at room temperature to give the corresponding dimeric esters in good yield. Georg Thieme Verlag Stuttgart.
Isopropoxyaluminum 1,1′-biphenyl-2-oxy-2′-perfluorooctanesulfonamide as a catalyst for Tishchenko reaction
Ooi, Takashi,Ohmatsu, Kohsuke,Sasaki, Kouji,Miura, Tomoya,Maruoka, Keiji
, p. 3191 - 3193 (2007/10/03)
Isopropoxyaluminum 1,1′-biphenyl-2-oxy-2′-perfluorooctanesulfonamide (3) has been evaluated as an aluminum-based catalyst for the Tishchenko reaction. Compound 3 was found to exert high catalytic activity in the reaction with aliphatic aldehydes and also enabled smooth dimerization of enolizable aldehydes. This advantage was highlighted by the quantitative formation of ethyl acetate from acetaldehyde by the present system.
Catalytic Meerwein-Ponndorf-Verley (MPV) and Oppenauer (OPP) reactions: Remarkable acceleration of the hydride transfer by powerful bidentate aluminum alkoxides
Ooi, Takashi,Miura, Tomoya,Itagaki, Yoshifumi,Ichikawa, Hayato,Maruoka, Keiji
, p. 279 - 291 (2007/10/03)
A highly efficient catalytic procedure for Meerwein-Ponndorf-Verley (MPV) reduction has been devised by employing (2,7-dimethyl-1,8-biphenylenedioxy)bis(dialkoxyaluminum) (3) as a catalyst. For example, reduction of 4-phenylcyclohexanone in CH2Cl2 with i-PrOH (1 equiv) as a hydride source in the presence of a catalytic amount of the in situ generated 3a (1 mol%) smoothly proceeded at room temperature within 1 hour to furnish 4-phenylcyclohexanol in 82% isolated yield. In sharp contrast, the conventional MPV reduction with stoichiometric Al(i-PrO)3 resulted in the recovery of the starting ketone under similar conditions. Our approach also enabled the reverse reaction of MPV reduction, i.e., Oppenauer (OPP) oxidation in a truly catalytic manner. Furthermore, these findings prompted us to develop a simultaneous intramolecular reduction/oxidation of hydroxy carbonyl substrates via the MPV reaction process in the presence of bidentate aluminum catalyst 1, where highly chemoselective hydride transfer from a secondary alcohol moiety to the remote carbonyl group took place. Finally, we demonstrate that the modern MPV system is applicable to high-speed, catalytic Tishchenko reactions. For instance, the dimerization product of cyclohexanecarbaldehyde was obtained in almost quantitative yield using only 0.2 mol% of catalyst 3a. Based on this result, highly stereoselective intramolecular Tishchenko reduction of a β-hydroxy ketone was also accomplished successfully.
Homoleptic lanthanide amides as homogeneous catalysts for alkyne hydroamination and the Tishchenko reaction
Buergstein, Markus R.,Berberich, Helga,Roesky, Peter W.
, p. 3078 - 3085 (2007/10/03)
The homoleptic bis(trimethylsilyl)amides of Group 3 metals and lanthanides of the general type [Ln{N(SiMe3)2}3] (1) (Ln = Y, lanthanide) represent a new class of Tishchenko precatalysts and, to a limited extent, precatalysts for the hydroamination/cyclization of aminoalkynes. It is shown that 1 is the most active catalyst for the Tishchenko reaction. This contribution presents investigations on the scope of the reaction, substrate selectivity, lanthanide-ion size-effect, and kinetic/ mechanistic aspects of the Tishchenko reaction catalyzed by 1. The turnover frequency is increased by the use of large-center metals and electron-with-drawing substrates. The reaction rate is second order with respect to the substrate. While donor atoms, such as nitrogen, oxygen, or sulfur, on the substrate decrease the turnover frequency, 1 shows a tolerance for a large number of functional groups. For the hydroamination/cyclization of aminoalkynes, 1 is less active than the well-known metallocene catalysts. On the other hand, 1 is much more readily accessible (one-step synthesis or commercially available), than the metallocenes and might therefore be an attractive alternative catalyst.
Simple Syntheses, Structural Diversity, and Tishchenko Reaction Catalysis of Neutral Homoleptic Rare Earth(II or III) 3,5-Di-tert-butylpyrazolates - The Structures of [Sc(tBu2pz)3], [Ln2(tBu2pz)6] (Ln = La, Nd, Yb, Lu), and [Eu4(tB2pz)8]
Deacon, Glen B.,Gitlits, Alex,Roesky, Peter W.,Buergstein, Markus R.,Lim, Kevin C.,Skelton, Brian W.,White, Allan H.
, p. 127 - 138 (2007/10/03)
The homoleptic rare-earth pyrazolate complexes [Sc(tBu2pz)3], [Ln2(tBu2pz)6] (Ln = La, Nd, Sm, Lu), [Eu4(tBu2pz)8] and the mixed oxidation state species [Yb2(tBu2pz)5] (tBu2pz = 3,5-di-tert-butylpyrazolate) have been prepared by a simple reaction between the corresponding rare-earth metal and 3,5-di-tert-butylpyrazole, in the presence of mercury, at elevated temperatures. In addition, [Yb2(tBu2pz)6] was prepared by redox transmetallation/ligand exchange between ytterbium, diphenylmercury(II) and tBu2pzH in toluene, whilst the same reactants in toluene under different conditions or in diethyl ether gave [Yb2(tBu2pz)5]. The complexes of the trivalent lanthanoids display dimeric structures [Ln2(tBu2pz)6] (Ln = La, Nd, Yb, Lu) with chelating η-terminal and η2:η2-bridging pyrazolate coordination. The considerably smaller Sc(3+) ion forms monomeric [Sc(tBu2pz)3] of putative D3h molecular symmetry, with pyrazolate ligands solely η2-bonded. [Eu4(tBu2pz)8] is a structurally remarkable tetranuclear Eu(II) complex with two types of europium centres in a linear array. The outer two are bonded to one terminal and two bridging pyrazolates, and the inner two are coordinated by four bridging ligands. Unprecedented μ-η5:η2 pyrazolate ligation is observed, with each outer Eu(2+) sandwiched between two η5-bonded pyrazolate groups, which are also η2-linked to an inner Eu(2+). The two inner Eu(2+) ions are linked together by two equally occupied components of each of two symmetry related, disordered pyrazolate groups with one component η4:η2 bridging and one η3:η2 bridging. [La2(tBu2pz)6] has also been shown to be a Tishchenko reaction catalyst with several organic substrates.
Catalytic, high-speed Tishchenko reaction using (2,7-dimethyl-1,8-biphenylenedioxy)bis(diisopropoxyaluminum) as a powerful bidentate catalyst
Ooi, Takashi,Miura, Tomoya,Takaya, Keisuke,Maruoka, Keiji
, p. 7695 - 7698 (2007/10/03)
Exceedingly high-speed Tishchenko reaction of various aldehydes can be realized by using a powerful, bidentate aluminum catalyst. This catalytic system is also applicable to the highly stereoselective intramolecular Tishchenko reduction of β-hydroxy ketones.
Homoleptic lanthanide amides as homogeneous catalyst for the Tishchenko reaction
Berberich, Helga,Roesky, Peter W.
, p. 1569 - 1571 (2007/10/03)
Known for about 25 years, the bis(trimethylsilyl)amides of Group 3 metals and lanthanides, M[N(SiMe3)2]3, are well suited as highly efficient catalysts for the dimerization of aldehydes [Tishchenko reaction, Eq. (1)].
