1192-62-7Relevant articles and documents
Preparation and Degradation of Rhodium and Iridium Diolefin Catalysts for the Acceptorless and Base-Free Dehydrogenation of Secondary Alcohols
Buil, Mariá L.,Collado, Alba,Esteruelas, Miguel A.,G? mez-Gallego, Mar,Izquierdo, Susana,Nicasio, Antonio I.,Onìate, Enrique,Sierra, Miguel A.
, p. 989 - 1003 (2021)
Rhodium and iridium diolefin catalysts for the acceptorless and base-free dehydrogenation of secondary alcohols have been prepared, and their degradation has been investigated, during the study of the reactivity of the dimers [M(μ-Cl)(I4-C8H12)]2 (M = Rh (1), Ir (2)) and [M(μ-OH)(I4-C8H12)]2 (M = Rh (3), Ir (4)) with 1,3-bis(6′-methyl-2′-pyridylimino)isoindoline (HBMePHI). Complex 1 reacts with HBMePHI, in dichloromethane, to afford equilibrium mixtures of 1, the mononuclear derivative RhCl(I4-C8H12){κ1-Npy-(HBMePHI)} (5), and the binuclear species [RhCl(I4-C8H12)]2{μ-Npy,Npy-(HBMePHI)} (6). Under the same conditions, complex 2 affords the iridium counterparts IrCl(I4-C8H12){κ1-Npy-(HBMePHI)} (7) and [IrCl(I4-C8H12)]2{μ-Npy,Npy-(HBMePHI)} (8). In contrast to chloride, one of the hydroxide groups of 3 and 4 promotes the deprotonation of HBMePHI to give [M(I4-C8H12)]2(μ-OH){μ-Npy,Niso-(BMePHI)} (M = Rh (9), Ir (10)), which are efficient precatalysts for the acceptorless and base-free dehydrogenation of secondary alcohols. In the presence of KOtBu, the [BMePHI]- ligand undergoes three different degradations: Alcoholysis of an exocyclic isoindoline-N double bond, alcoholysis of a pyridyl-N bond, and opening of the five-membered ring of the isoindoline core.
Selective oxidation of alcohols in the presence of an Os/O2-system
D?bler, Christian,Mehltretter, Gerald M,Sundermeier, Uta,Eckert, Markus,Militzer, Hans-Christian,Beller, Matthias
, p. 8447 - 8449 (2001)
The osmium-catalyzed oxidation of alcohols with molecular oxygen to give aldehydes in good to excellent yields has been developed. Best results are obtained by using a buffered two-phase system with a constant pH of 10.4. Under optimized reaction conditions a remarkable catalyst productivity (TON up to 16600) is observed.
Comparison of 2-acetylfuran formation between ribose and glucose in the Maillard reaction
Wang, Yu,Ho, Chi-Tang
, p. 11997 - 12001 (2008)
Sugar type is a major factor regulating the reaction rates and pathways in Maillard reaction. Ribose and glucose were used to compare their reactivities and pathways of 2-acetylfuran formation. A stable isotope labeling method was used to study their reactivity. A 1:1 mixture of [13C 6]glucose and unlabeled ribose (or other unlabeled sugar) was reacted with proline at 145 °C for 40 min. The reactivity of each sugar was revealed by the ratio of isotopomers. The reactivity of sugars in 2-acetylfuran formation decreased in the order ribose, fructose, glucose, rhamnose, and sucrose. This method simplified the reaction system and the calculation process and gave a direct comparison of reactivity as seen via mass spectrum. The difference between glucose and ribose in 2-acetylfuran formation was that glucose could form 2-acetylfuran directly from cyclization of its intact carbon skeleton, whereas ribose first underwent degradation into fragments before forming a six-carbon unit leading to 2-acetylfuran. In the presence of cysteine, ribose could not generate 2-acetylfuran at a detectable level. When ribose was reacted with glycine, formaldehyde generated from glycine combined with ribose to form 2-acetylfuran. In other amino acids, a symmetric structure of the ribose intermediate was formed, making fragmentation more complicated.
Copper-Catalyzed Stille Cross-Coupling Reaction and Application in the Synthesis of the Spliceostatin Core Structure
Ghosh, Arun K.,Born, Joshua R.,Veitschegger, Anne M.,Jurica, Melissa S.
, p. 8111 - 8120 (2020)
An efficient palladium-free Stille cross-coupling reaction of allylic bromides and functionalized organostannylfuran using catalytic copper halide has been developed. The coupling reaction was optimized using CuI and low catalyst loading (down to 5 mol %). The reaction was conveniently carried out at ambient temperature in the presence of inorganic base to afford the coupling product in good-to-excellent yields. The utility of this reaction was demonstrated in the synthesis of a furan with sensitive functionalities. A sulfolene moiety was utilized as a masking group for the sensitive diene. Noyori asymmetric reduction, Achmatowicz reaction, and Kishi reduction steps converted sulfolene to a highly substituted tetrahydropyran intermediate used in the synthesis of the highly potent antitumor agents, spliceostatins, and their derivatives.
Oxidation of alcohols by transfer hydrogenation: driving the equilibrium with an intramolecular trap
Wise, Nicola J.,Williams, Jonathan M.J.
, p. 3639 - 3641 (2007)
Levulinic acid and its esters participate in transfer hydrogenation with a range of secondary alcohols. Reduction of the levulinate leads to cyclisation into a γ-lactone, thereby acting as an oxidant for alcohols without the need for a large excess of reagents.
Enantioselective microbial oxidation of 1-arylethanol in an organic solvent
Nakamura, Kaoru,Inoue, Yuko,Ohno, Atsuyoshi
, p. 4375 - 4376 (1994)
Reactivity in enantioselective oxidation of 1-arylethanol by Geotrichum candidum is improved when the microbe is entrapped with a water-adsorbent polymer and the reaction is conducted in hexane. Cyclohexanone as an additive improves the rate of oxidation as well as ee of the remained alcohol.
Rearrangements of some furan and benzofuran 1,5,-dienols
Martin,Wurster,Boylan,Borzilleri,Engel,Walsh
, p. 8395 - 8398 (1993)
Isomers of 1-(2-furyl)-methyl-3-buten-ols and their benzofuran analogs were studied for their oxy-Cope and anionic oxy-Cope reactivity.
Potassium ferrate on wet alumina: Preparation and reactivity
Caddick,Murtagh,Weaving
, p. 9365 - 9373 (2000)
The use of a wet alumina/potassium ferrate system for the oxidation of a range of activated alcohols is described. Studies are presented which delineate the scope and limitation of the procedure and include a new carbon-carbon bond cleavage reaction. (C) 2000 Elsevier Science Ltd.
Examining of athermal effects in microwave-induced glucose/glycine reaction and degradation of polysaccharide from Porphyra yezoensis
Zhou, Cunshan,Yu, Xiaojie,Ma, Haile,Liu, Shulan,Qin, Xiaopei,Yagoub, Abu El-Gasim A.,Owusu, John
, p. 38 - 44 (2013)
Many reports claim the existence of athermal effects in microwave-induced reactions, and this challenge the assumption that the thermal effect (heating) is the sole factor in microwave heating. Therefore, microwave-induced Maillard reaction of d-glucose/g
Iron–PNP-Pincer-Catalyzed Transfer Dehydrogenation of Secondary Alcohols
Budweg, Svenja,Wei, Zhihong,Jiao, Haijun,Junge, Kathrin,Beller, Matthias
, (2019)
The well-defined iron PNP pincer complex catalyst [Fe(H)(BH4)(CO)(HN{CH2CH2P(iPr)2}2] was used for the catalytic dehydrogenation of secondary alcohols to give the corresponding ketones. Using acetone as inexpensive hydrogen acceptor enables the oxidation with good to excellent yields. DFT computations indicate an outer-sphere mechanism and support the importance of an acceptor to achieve this transformation under milder conditions.
