6656-60-6Relevant academic research and scientific papers
Gold N-Heterocyclic Carbene Catalysts for the Hydrofluorination of Alkynes Using Hydrofluoric Acid: Reaction Scope, Mechanistic Studies and the Tracking of Elusive Intermediates
Bédard, Sandrine,Cavallo, Luigi,Falivene, Laura,Gauthier, Rapha?l,Nolan, Steven P.,Paquin, Jean-Fran?ois,Saab, Marina,Tzouras, Nikolaos V.,Van Hecke, Kristof,Zhang, Ziyun
, (2021/12/09)
An efficient and chemoselective methodology deploying gold-N-heterocyclic carbene (NHC) complexes as catalysts in the hydrofluorination of terminal alkynes using aqueous HF has been developed. Mechanistic studies shed light on an in situ generated catalyst, formed by the reaction of Br?nsted basic gold pre-catalysts with HF in water, which exhibits the highest reactivity and chemoselectivity. The catalytic system has a wide alkyl substituted-substrate scope, and stoichiometric as well as catalytic reactions with tailor-designed gold pre-catalysts enable the identification of various gold species involved along the catalytic cycle. Computational studies aid in understanding the chemoselectivity observed through examination of key mechanistic steps for phosphine- and NHC-coordinated gold species bearing the triflate counterion and the elusive key complex bearing a bifluoride counterion.
Method for synthesizing 2, 4-dimethyl pyrimidine-5-alcohol serving as intermediate of Leibolifera
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Paragraph 0036-0039; 0044-0046, (2021/08/07)
The invention discloses a method for synthesizing 2, 4-dimethyl pyrimidine-5-alcohol serving as an intermediate of Lemborexant , and aims to solve the problems of safety risk and heavy environmental pollution of the 2, 4-dimethyl pyrimidine-5-alcohol in i
Oxidative Cleavage of Alkenes by O2with a Non-Heme Manganese Catalyst
Bennett, Elliot L.,Brookfield, Adam,Guan, Renpeng,Huang, Zhiliang,Mcinnes, Eric J. L.,Robertson, Craig M.,Shanmugam, Muralidharan,Xiao, Jianliang
supporting information, p. 10005 - 10013 (2021/07/19)
The oxidative cleavage of C═C double bonds with molecular oxygen to produce carbonyl compounds is an important transformation in chemical and pharmaceutical synthesis. In nature, enzymes containing the first-row transition metals, particularly heme and non-heme iron-dependent enzymes, readily activate O2 and oxidatively cleave C═C bonds with exquisite precision under ambient conditions. The reaction remains challenging for synthetic chemists, however. There are only a small number of known synthetic metal catalysts that allow for the oxidative cleavage of alkenes at an atmospheric pressure of O2, with very few known to catalyze the cleavage of nonactivated alkenes. In this work, we describe a light-driven, Mn-catalyzed protocol for the selective oxidation of alkenes to carbonyls under 1 atm of O2. For the first time, aromatic as well as various nonactivated aliphatic alkenes could be oxidized to afford ketones and aldehydes under clean, mild conditions with a first row, biorelevant metal catalyst. Moreover, the protocol shows a very good functional group tolerance. Mechanistic investigation suggests that Mn-oxo species, including an asymmetric, mixed-valent bis(μ-oxo)-Mn(III,IV) complex, are involved in the oxidation, and the solvent methanol participates in O2 activation that leads to the formation of the oxo species.
Oxidative C-H Acyloxylation of Acetone with Carboxylic Acids under Iodine Catalysis
Zhou, Xiao-Yu,Chen, Xia
supporting information, p. 1654 - 1662 (2021/01/21)
Iodine-catalyzed oxidative C(sp 3)-H acyloxylation of acetone with carboxylic acids has been developed. The method employs iodide as catalyst and sodium chlorite as oxidant. Substituted benzoic acids, naphthoic acids and heteroaromatic carboxyl
KI catalyzed C–H functionalization of acetone for the synthesis of 2-oxopropyl hetero-aromatic carboxylates
Zhou, Xiao-Yu,Chen, Xia,Liu, Hai-Long
supporting information, p. 1556 - 1563 (2021/03/15)
KI catalyzed C–H functionalization of acetone with hetero-aromatic carboxylic acids has been developed. With potassium iodide as catalyst and sodium chlorite as oxidant, cascade reaction including α-H electrophilic substitution of acetone and nucleophilic
1,2-Dibromoethane and KI mediated α-acyloxylation of ketones with carboxylic acids
Wang, Xujie,Li, Gangsheng,Yang, Yanan,Jiang, Jianshuang,Feng, Ziming,Zhang, Peicheng
, p. 711 - 714 (2019/09/30)
The 1,2-dibromoethane- and KI-mediated α-acyloxylation of ketones is reported in moderate to good yield without the use of transition metals and strong oxidants. Various acids are well tolerated with wide functional group compatibility. An 1,2-dibromoethane- and KI-catalysed reaction mechanism is proposed based on the results of control experiments.
Microwave-Enhanced Coupling of Carboxylic Acids with Liquid Ketones and Cyclic Ethers Using Tetrabutylammonium Iodide/ t-Butyl Hydroperoxide
Macías-Benítez, Pablo,Moreno-Dorado, F. Javier,Guerra, Francisco M.
, p. 6027 - 6043 (2020/05/22)
The oxidative coupling of carboxylic acids with liquid ketones and cyclic ethers has been accomplished in minutes using t-butyl hydroperoxide in the presence of tetrabutylammonium iodide under microwave irradiation in the absence of a solvent. In addition to drastically shortening the reaction times, the use of microwaves resulted, in general, in yields equal to or higher than those obtained by conventional heating.
Catalytic Wacker-type Oxidations Using Visible Light Photoredox Catalysis
Ho, Yee Ann,Paffenholz, Eva,Kim, Hyun Jin,Orgis, Benjamin,Rueping, Magnus,Fabry, David C.
, p. 1889 - 1892 (2019/03/17)
A combined palladium/photoredox catalytic system for the efficient oxidation of terminal olefins to the corresponding methyl ketones is presented. The interplay of air, water, and light leads to a protocol in which the stoichiometric oxidants required for oxidative palladium catalysis are substituted with catalytic, single-electron transfer processes. Detailed mechanistic investigations revealed the role of the key components, in situ generated species, and catalysts. A broad range of substrates was examined in homogeneous as well as heterogeneous photoredox protocols, delivering the desired products in good yields.
Group VIII carbamoyl complexes as catalysts for alkyne hydrocarboxylation and electrochemical proton reduction
Barik, Chandan Kr,Tessensohn, Malcolm E.,Webster, Richard D.,Leong, Weng Kee
, p. 40 - 44 (2019/04/01)
A series of group VIII carbamoyl complexes, [M(2-NHC(O)C5H4N)(CO)2(2-SC5H4N)] [where M = Fe, Ru and Os], was found to be efficient and regioselective catalysts for the intramolecular hydroxycarboxylat
TBAI/TBHP mediated oxidative cross coupling of ketones with phenols and carboxylic acids: Direct access to benzofurans
Santhosh Kumar,Ravikumar,Chinna Ashalu,Rajender Reddy
supporting information, p. 33 - 37 (2017/12/11)
TBAI/TBHP mediated oxidative cross coupling of phenols and carboxylic acids with ketones has been reported under metal-free, base free, solvent free conditions enabling environmentally benign synthesis of aryloxyketones, acyloxy ketones and benzofurans. Phenoxyketones and acyloxylcarbonyl compounds were synthesized in good to high yields, where as benzofurans were synthesized in moderate yields. This method is operationally simple, works under mild conditions, using commercially available as well as inexpensive TBAI and an oxidant TBHP.
