13740-70-0Relevant academic research and scientific papers
Combined Photoredox and Carbene Catalysis for the Synthesis of Ketones from Carboxylic Acids
Betori, Rick C.,Davies, Anna V.,Fitzpatrick, Keegan P.,Scheidt, Karl A.
supporting information, p. 9143 - 9148 (2020/03/30)
As a key element in the construction of complex organic scaffolds, the formation of C?C bonds remains a challenge in the field of synthetic organic chemistry. Recent advancements in single-electron chemistry have enabled new methods for the formation of various C?C bonds. Disclosed herein is the development of a novel single-electron reduction of acyl azoliums for the formation of ketones from carboxylic acids. Facile construction of the acyl azolium in situ followed by a radical–radical coupling was made possible merging N-heterocyclic carbene (NHC) and photoredox catalysis. The utility of this protocol in synthesis was showcased in the late-stage functionalization of a variety of pharmaceutical compounds. Preliminary investigations using chiral NHCs demonstrate that enantioselectivity can be achieved, showcasing the advantages of this protocol over alternative methodologies.
N-Heterocyclic Carbene-Catalyzed Decarboxylative Alkylation of Aldehydes
Ishii, Takuya,Kakeno, Yuki,Nagao, Kazunori,Ohmiya, Hirohisa
supporting information, p. 3854 - 3858 (2019/04/25)
We found that N-heterocyclic carbene catalysis promoted the unprecedented decarboxylative coupling of aryl aldehydes and tertiary or secondary alkyl carboxylic acid-derived redox-active esters to produce aryl alkyl ketones. The mild and transition-metal-free reaction conditions are attractive features of this method. The power of this protocol was demonstrated by the functionalization of pharmaceutical drugs and natural product. A reaction pathway involving single electron transfer from an enolate form of Breslow intermediate to a redox ester followed by recombination of the resultant radical pair to form a carbon-carbon bond is proposed.
N-Heterocyclic Carbene-Catalyzed Radical Relay Enabling Vicinal Alkylacylation of Alkenes
Ishii, Takuya,Ota, Kenji,Nagao, Kazunori,Ohmiya, Hirohisa
supporting information, p. 14073 - 14077 (2019/10/11)
The N-heterocyclic carbene-catalyzed radical relay enables the vicinal alkylacylation of styrenes, acrylates and acrylonitrile using aldehydes and tertiary alkyl carboxylic acid-derived redox-active esters. This protocol introduces tertiary alkyl groups and acyl groups to C-C double bonds with complete regioselectivity to produce functionalized ketone derivatives. The radical relay mechanism involves single electron transfer from the enolate form of a Breslow intermediate and radical addition of the resultant alkyl radical to the alkene followed by radical-radical coupling.
Pinacol Rearrangement and Direct Nucleophilic Substitution of Allylic Alcohols Promoted by Graphene Oxide and Graphene Oxide CO2H
Gómez-Martínez, Melania,Baeza, Alejandro,Alonso, Diego A.
, p. 1032 - 1039 (2017/03/27)
Graphene oxide (GO) and carboxylic acid functionalized GO (GO–CO2H) have been found to efficiently promote the heterogeneous and environmentally friendly pinacol rearrangement of 1,2-diols and the direct nucleophilic substitution of allylic alcohols. In general, high yields and regioselectivities are obtained in both reactions using 20 wt % of catalyst loading and mild reaction conditions.
Fe(III)-mediated isomerization of α,α-diarylallylic alcohols to ketones: Via radical 1,2-aryl migration
Deng, Ziyang,Chen, Changwei,Cui, Sunliang
, p. 93753 - 93755 (2016/10/18)
An Fe(iii)-mediated radical 1,2-aryl migration of α,α-diarylallylic alcohols for the isomerization to ketones is described. The Fe(acac)3-silane would convert the alkene to an alkyl radical and initiates a 1,2-aryl migration-oxidation process. Thus Fe(acac)3 serves as an olefin hydrogen atom transfer initiator and oxidant, while various allylic alcohols could isomerize to ketones in moderate to good yields.
Heteropolytungstic acids incorporated in an ordered mesoporous zirconia framework as efficient oxidation catalysts
Skliri, Euaggelia,Lykakis, Ioannis N.,Armatas, Gerasimos S.
, p. 8402 - 8409 (2014/02/14)
Ordered mesoporous composite catalysts consisting of nanocrystalline tetragonal ZrO2 and heteropolytungstic clusters, i.e. 12-phosphotungstic (PTA) and 12-silicotungstic (STA) acids, were prepared via a surfactant-assisted co-polymerization route. According to the X-ray diffraction, transmission electron microscopy and N2 physisorption measurements, the resultant materials possess a well-defined mesoscopic order ranging from wormhole to hexagonal pore structure and exhibit large internal surface area (126-229 m2 g-1) and quite narrow pore size distribution (ca. 2.2-2.6 nm in diameter). Energy dispersive X-ray microanalysis and infrared spectroscopy confirms that the heteropoly clusters are well dispersed within the zirconia matrix, while preserving intact their Keggin structure. The inclusion of PTA and STA clusters in the mesoporous framework has a beneficial effect on the catalytic activity of these materials. Although zirconium oxide and heteropoly acids alone show little catalytic activity, the ZrO 2-PTA and ZrO2-STA heterostructures exhibit surprisingly high activity in hydrogen peroxide mediated oxidation of 1,1-diphenyl-2- methylpropene under mild conditions. Indeed, the mesoporous ZrO2-STA composite sample loaded with 5 wt% STA shows a conversion rate that is 17 times higher than the mesoporous ZrO2. The catalytic activity of these materials is related to the spatial distribution of heteropoly acids in zirconia matrix and possible synergistic interactions between the incorporated Keggin units and Zr(iv) oxohydroxide species.
Praseodymium-induced pinacol formation
Drapo, Jeanette R.,Priefer, Ronny
experimental part, p. 85 - 92 (2009/04/07)
In an attempt to regenerate Ti(0) from TiOx for possible application in a catalytic McMurry coupling reaction, a praseodymium-based pinacol reaction was uncovered. This reaction formed the two products 2,3-diphenyl-2,3-butanediol (3) and α,β-dimethyl-α-phenyl-β-[(trimethylsilyl)oxy]- benzene-ethanol (6) in a 1:3 ratio. Copyright Taylor & Francis Group, LLC.
Enantioselective hydrogenation and transfer hydrogenation of bulky ketones catalysed by a ruthenium complex of a chiral tridentate ligand
Diaz-Valenzuela, M. Belen,Phillips, Scott D.,France, Marcia B.,Gunn, Mary E.,Clarke, Matthew L.
supporting information; experimental part, p. 1227 - 1232 (2009/08/10)
A study on the enantioselective hydrogenation of tertiary alkyl ketones catalysed by a novel class of tridentate-Ru complex is reported. In contrast to the extensively studied [RuCl2(diphos)(di-primary amine)] complexes, this new class of hydro
Asymmetrie allylation of methyl ketones by using chiral phenyl carbinols
Tietze, Lutz F.,Kinzel, Tom,Wolfram, Thomas
experimental part, p. 6199 - 6210 (2010/03/01)
Novel chiral auxiliaries for the stereoselective allylation of aliphatic methyl ketones with allyltrimethylsilane and their use in the synthesis of homoallylic ethers are described. In a multicomponent domino process catalyzed by trifluoromethanesulfonic
Reactions of methylenecyclobutanes with silver acetate and iodine
Jiang, Min,Liu, Le-Ping,Shi, Min
, p. 9599 - 9604 (2008/02/11)
Methylenecyclobutanes undergo an interesting rearrangement reaction in the presence of silver acetate and iodine at room temperature (20 °C) in dichloromethane to give the corresponding aryl-(1-arylcyclobutyl)methanones in good to high yields within short
