5650-41-9Relevant academic research and scientific papers
Porous organic polymer-supported manganese catalysts with tunable wettability for efficient oxidation of secondary alcohols
Lin, Jin,Sun, Wei,Wang, Bingyang,Xia, Chungu
, p. 87 - 95 (2022/01/22)
Porous organic polymers (POPs) feature high surface areas, tunable components, and designable hierarchical pores, thus showing versatile applications including catalysis, separation, gas storage and so on. However, the inherently hydrophobic property may be unfavorable for the catalytic reaction that involves hydrophilic reactants. By using the hydrophilic principle of the amide bond, R-NH-CO-R can be constructed in the porous frameworks to regulate the wettability. Herein, we report the construction of an amphiphilic and hierarchical porous Mn-N4 catalyst via the solvothermal copolymerization, in which N,N-methylenebisacrylamide is used as a hydrophilic monomer. This POP-based manganese catalyst can effectively promote the oxidation of secondary alcohol to produce the ketone using aqueous hydrogen peroxide as the oxidant under mild conditions. Note that this amphiphilic catalyst displays high catalytic activity as its homogeneous counterpart in the selective oxidation of alcohols. The present work has provided a successful approach for improving the catalytic activity by tuning the wettability of POP-based heterogeneous catalysts.
Chemoselective Electrochemical Oxidation of Secondary Alcohols Using a Recyclable Chloride-Based Mediator
Sommer, Florian,Kappe, C. Oliver,Cantillo, David
supporting information, p. 166 - 170 (2021/06/16)
Selective anodic oxidation of alcohols in the presence of other functional groups can be accomplished by using nitroxyl radical mediators. However, the electrochemical chemoselective oxidation of secondary alcohols in the presence of primary alcohols is a
Catalytic Net Oxidative C-C Activation and Silylation of Cyclopropanols with a Traceless Acetal Directing Group
Avullala, Thirupataiah,Nguyen, Hiep H.,Dakarapu, Udaya Sree,Asgari, Parham,Hua, Yuanda,Jeon, Junha
, p. 1764 - 1774 (2022/02/07)
Redox-neutral carbon-carbon (C-C) bond activation and functionalization strategies of cyclopropanols that give metallo homoenolate have offered merits to construct a range of useful β-functionalized ketones in an inverse-polarity fashion. Discovery and id
o-Quinone methide with overcrowded olefin component as a dehydridation catalyst under aerobic photoirradiation conditions
Uraguchi, Daisuke,Kato, Kohsuke,Ooi, Takashi
, p. 2778 - 2783 (2021/03/14)
Ano-quinone methide (o-QM) featuring an overcrowded olefinic framework is introduced, which exhibits dehydridation activity owing to its enhanced zwitterionic character, particularly through photoexcitation. The characteristics of thiso-QM enable the operation of dehydridative catalysis in the oxidation of benzylic secondary alcohols under aerobic photoirradiation conditions. An experimental analysis and density functional theory calculations provide mechanistic insights; the ground-state zwitterionic intermediate abstracts a hydride and proton simultaneously, and the active oxygen species facilitate catalyst regeneration.
4CzIPN catalyzed photochemical oxidation of benzylic alcohols
Zhang, Heng,Guo, Tianyun,Wu, Mingzhong,Huo, Xing,Tang, Shouchu,Wang, Xiaolei,Liu, Jian
supporting information, (2021/02/20)
A green photoredox oxidation of benzylic primary and secondary alcohols to aldehydes and ketones with air as an oxidant was reported. The oxidation shows broad substrate scope and excellent selectivity over benzylic alcohols to the aliphatic alcohols. Further mechanistic studies revealed a quinuclidine mediated HAT process, and blue LEDs promoted 4CzlPN (1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene) photoredox cycle were involved in our oxidation.
Catalytic Aerobic Oxidation of Alkenes with Ferric Boroperoxo Porphyrin Complex; Reduction of Oxygen by Iron Porphyrin
Kimura, Kento,Kurahashi, Takuya,Matsubara, Seijiro,Murano, Shunpei
supporting information, p. 2493 - 2497 (2021/12/29)
We herein describe the development of a mild and selective catalytic aerobic oxidation process of olefins. This catalytic aerobic oxidation reaction was designed based on experimental and spectroscopic evidence assessing the reduction of atmospheric oxygen using a ferric porphyrin complex and pinacolborane to form a ferric boroperoxo porphyrin complex as an oxidizing species. The ferric boroperoxo porphyrin complex can be utilized as an in-situ generated intermediate in the catalytic aerobic oxidation of alkenes under ambient conditions to form oxidation products that differ from those obtained using previously reported ferric porphyrin catalysis. Moreover, the mild reaction conditions allow chemoselective oxidation to be achieved.
Visible-Spectrum Solar-Light-Mediated Benzylic C-H Oxygenation Using 9,10-Dibromoanthracene As an Initiator
Santra, Sourav K.,Szpilman, Alex M.
, p. 1164 - 1171 (2020/12/23)
We report a visible-light-mediated benzylic C-H oxygenation reaction. The reaction is initiated by solar light or the blue LED activation of 9,10-dibromoanthracene in a reaction with oxygen and takes place at ambient temperature and air pressure. Secondary benzylic positions are oxygenated to ketones, while tertiary benzylic carbons are oxygenated to give hydroperoxides. Notably, cumene hydroperoxide is produced in a higher yield and at milder conditions than the currently employed industrial conditions.
LIGHT INDUCED CATALYTIC C-H OXYGENATION OF ALKANES
-
Paragraph 00219-00220 00223; 00225, (2021/04/02)
A method of oxygenating a benzylic C-H bond is provided. The method comprises light induced activation of an initiator and subsequent reaction with oxygen, resulting in the formation of free radicals. Subsequently, free radicals catalyze the reaction of the benzylic C-H bond with oxygen, thereby forming an oxygenated compound.
Catalytic C(β)-O Bond Cleavage of Lignin in a One-Step Reaction Enabled by a Spin-Center Shift
Zhu, Qilei,Nocera, Daniel G.
, p. 14181 - 14187 (2021/11/27)
A challenge to the utilization of lignin as a feedstock for aromatic fine chemicals lies in selective cleavage of copious β-O-4 linkages. A photocatalytic strategy for the selective cleavage of the C(β)-O bonds of model substrates and natural lignin extracts is achieved by a redox-neutral, catalytic cycle that does not require stoichiometric reagents. Mechanistic studies reveal the generation of a thiyl radical, which is derived from a cystine-derived H-atom transfer catalyst, initiates a spin-center shift (SCS) that leads to C(β)-O bond cleavage. The SCS reactivity is reminiscent of the C(β)-O bond cleavage chemistry that occurs in the active site of ribonucleotide reductase.
All at once arrangement of both oxygen atoms of dioxygen into aliphatic C(sp3)-C(sp3) bonds for hydroxyketone difunctionalization
Qiao, Xiaofeng,Lin, Yuhan,Li, Jiazhen,Ma, Wanhong,Zhao, Jincai
, p. 770 - 777 (2021/04/09)
Both β- and γ- hydroxyketone structures are important units in biologically active molecules, synthetic drugs and fine chemicals. Although there are some routes available for their manufacture from pre-functionalized groups on one or two matrix molecule(s), the approaches to simply and simultaneously deposit two oxygen atoms from dioxygen into two specific C(sp3) positions of pure saturated hydrocarbons have rarely succeeded because they are involved in the targeted activation of three inert C-H σ bonds all at once. Here, we show that a TiO2-CH3CN photocatalytic suspension system enables the insertion of dioxygen into one C(sp3)-C(sp3) bond of strained cycloparaffin derivatives, by which difunctionalized hydroxyketone products are obtained in a one-pot reaction. With the cleavage event to release strain as the directional driving force, as-designed photocatalytic reaction systems show 21 examples of β-hydroxyketone products with 31%–76% isolated yields for three-membered ring derivatives and 5 examples of γ-hydroxyketone products with 30%–63% isolated yields for four-membered ring substrates. 18O isotopic labeling experiments using 18O2, Ti18O2 and intentionally added H218O, respectively, indicated that both oxygen atoms of hydroxyketone products were exclusively from dioxygen, suggesting a previously unknown H+/TiO2-e? catalyzed arrangement pathway of the hydroperoxide intermediate to convert dioxygen into hydroxyketone units. [Figure not available: see fulltext.]
