2021-28-5Relevant articles and documents
Sugi,Bando
, p. 727,728-730 (1976)
Peripherally cyclometalated iridium complexes of dipyridylporphyrin
Yoshida, Keita,Nakashima, Takumi,Yamaguchi, Shigeru,Osuka, Atsuhiro,Shinokubo, Hiroshi
, p. 8773 - 8775 (2011)
Two types of novel iridium pincer complexes bearing a porphyrin backbone were synthesized and characterized from dipyridylporphyrin. One of the complexes has a Lewis acidic site on the iridium center in the mer-coordination mode. The other complex takes the fac-coordination, which is rarely observed in benzene-based pincer complexes. The Royal Society of Chemistry 2011.
A mild method for protodesilylation of α-dimethylphenylsilyl ester substrates
Poliskie, G. Michelle,Mader, Mary M.,Van Well, Renate
, p. 589 - 592 (1999)
Mild conditions (1.2 eq. Hg(OAc)2, 1.2 eq. TBAF in 1:1 MeOH/THF; 35 min at 0 °C) have been developed for the protodesilylation of α- dimethylphenylsilyl esters. An enolate-dependent mechanism for the reaction was supported through studies indicating the clean incorporation of deuterium. To further investigate the mechanism, the optimal conditions as well as the kinetics of the reaction were explored.
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Ono,Hayashi
, p. 11,12 (1953)
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Palladium(0) nanoparticles on glass-polymer composite materials as recyclable catalysts: A comparison study on their use in batch and continuous flow processes
Mennecke, Klaas,Cecilia, Raul,Glasnov, Toma N.,Gruhl, Susanne,Vogt, Carla,Feldhoff, Armin,Vargas, M. A. Larrubia,Kappe, C. Oliver,Kunz, Ulrich,Kirschninga, Andreas
, p. 717 - 730 (2008)
Palladium particles were generated by reduction of palladate anions bound to an ion exchange resin inside microreactors. The size and distribution of the palladium particles differed substantially depending on the degree of cross-linking and the density of ion exchange sites on the polymer/glass composites, the latter parameter having a larger influence than the former. The polymer phase of the composite materials was used for the loading with clusters composed of palladium particles which are 1 to 10 nm in diameter. The reactivity and stability of six different palladium-doped polymer/glass composite samples for transfer hydrogenations was investigated both under conventional and microwave heating in the batch mode as well as under continuous flow conditions using the cyclohexene-promoted transfer hydrogenation of ethyl cinnamate as a model reaction. Regarding the heating method it was found that catalysts that are composed of larger metal particles perform better under microwave irradiating conditions whereas samples with smaller particle sizes perform better under conventional heating. Comparing batch experiments with flow-through experiments the latter technique gives better conversion. Reusability was better in microwave heated experiments than in traditional heating.
Catalyst type and concentration dependence in catalytic transfer hydrogenolysis of α,β-unsaturated carbonyls and nitriles via ammonium formate
Ram,Spicer
, p. 2683 - 2690 (1992)
The catalytic reduction of a variety of α,β-unsaturated compounds into saturated analogs in the presence of other reducible moieties is described using ammonium formate as a hydrogen source. The rate dependence on the concentration of Pd-C catalyst as well as on 5% Pd-BaSO4 and Ra-Ni are also characterized.
The relative reactivities of various unsaturated compounds towards diisopropyloxy(η2-cyclopentene)titanium
Cadoret, Frédéric,Six, Yvan
, p. 5491 - 5495 (2007)
Competition experiments were performed by adding pre-formed solutions of diisopropyloxy(η2-cyclopentene)titanium in diethyl ether to various mixtures of unsaturated compounds at low temperature, establishing the following reactivity scale: aldehyde > nitrile > ketone > terminal alkyne > internal alkyne > terminal alkene > ester, carbonate.
Esterification or Thioesterification of Carboxylic Acids with Alcohols or Thiols Using Amphipathic Monolith-SO3H Resin
Ichihara, Shuta,Ishida, Moeka,Ito, Ryo,Kato, Ayumu,Monguchi, Yasunari,Nakamura, Shinji,Park, Kwihwan,Sajiki, Hironao,Takada, Hitoshi,Wakayama, Fumika,Yamada, Tsuyoshi,Yamada, Yutaro
, p. 2702 - 2710 (2022/01/19)
We have developed a method for the esterification of carboxylic acids with alcohols using amphipathic, monolithic-resin bearing sulfonic acid moieties as cation exchange functions (monolith-SO3H). Monolith-SO3H efficiently catalyzed the esterification of aromatic and aliphatic carboxylic acids with various primary and secondary alcohols (1.55.0 equiv) in toluene at 6080 °C without the need to remove water generated during the reaction. The amphipathic property of monolith-SO3H facilitates dehydration due to its capacity for water absorption. This reaction was also applicable to thioesterification, wherein the corresponding thioesters were obtained in excellent yield using only 2.0 equiv of thiol in toluene, although heating at 120 °C was required. Moreover, monolith-SO3H was separable from the reaction mixtures by simple filtration and reused for at least five runs without decreasing the catalytic activity.
Manganese-catalyzed homogeneous hydrogenation of ketones and conjugate reduction of α,β-unsaturated carboxylic acid derivatives: A chemoselective, robust, and phosphine-free in situ-protocol
Topf, Christoph,Vielhaber, Thomas
, (2021/07/10)
We communicate a user-friendly and glove-box-free catalytic protocol for the manganese-catalyzed hydrogenation of ketones and conjugated C[dbnd]C[sbnd]bonds of esters and nitriles. The respective catalyst is readily assembled in situ from the privileged [Mn(CO)5Br] precursor and cheap 2-picolylamine. The catalytic transformations were performed in the presence of t-BuOK whereby the corresponding hydrogenation products were obtained in good to excellent yields. The described system offers a brisk and atom-efficient access to both secondary alcohols and saturated esters avoiding the use of oxygen-sensitive and expensive phosphine-based ligands.
