70770-06-8Relevant articles and documents
Enabling the Use of Alkyl Thianthrenium Salts in Cross-Coupling Reactions by Copper Catalysis
Chen, Cheng,Lu, Hongjian,Shi, Zhuangzhi,Wang, Minyan,Zhao, Binlin
, p. 21756 - 21760 (2021/08/30)
Alkyl groups are one of the most widely used groups in organic synthesis. Here, a a series of thianthrenium salts have been synthesized that act as reliable alkylation reagents and readily engage in copper-catalyzed Sonogashira reactions to build C(sp3)?C(sp) bonds under mild photochemical conditions. Diverse alkyl thianthrenium salts, including methyl and disubstituted thianthrenium salts, are employed with great functional breadth, since sensitive Cl, Br, and I atoms, which are poorly tolerated in conventional approaches, are compatible. The generality of the developed alkyl reagents has also been demonstrated in copper-catalyzed Kumada reactions.
Zirconium-catalysed direct substitution of alcohols: enhancing the selectivity by kinetic analysis
Camaj, David,Carlsson, Robin,Dalla-Santa, Oscar,Lill, Malin,Lundberg, Helena,Margarita, Cristiana,Ramstr?m, Anja,Tu?on, Hernando,Villo, Piret
, p. 7420 - 7430 (2021/11/23)
Kinetic analysis was used as a tool for rational optimization of a catalytic, direct substitution of alcohols to enable the selective formation of unsymmetrical ethers, thioethers, and Friedel-Crafts alkylation products using a moisture-tolerant and commercially available zirconium complex (2 to 8 mol%). Operating in air and in the absence of dehydration techniques, the protocol furnished a variety of products in high yields, including glycosylated alcohols and sterically hindered ethers. In addition, the kinetic studies provided mechanistic insight into the network of parallel transformations that take place in the reaction, and helped to elucidate the nature of the operating catalyst.
Hydrogenation reaction method
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Paragraph 0034; 0177-0180, (2020/05/14)
The invention relates to a hydrogenation reaction method, and belongs to the technical field of organic synthesis. The hydrogenation reaction method provided by the invention comprises the following steps: carrying out a hydrogen transfer reaction on a hydrogen acceptor compound, pinacol borane and a catalyst in a solvent in the presence of proton hydrogen, so that the hydrogen acceptor compound is subjected to a hydrogenation reaction; the catalyst is one or more than two of a palladium catalyst, an iridium catalyst and a rhodium catalyst; the hydrogen acceptor compound comprises one or morethan two functional groups of carbon-carbon double bonds, carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogentriple bonds and epoxy. The method is mild in reaction condition, easy to operate, high in yield, short in reaction time, wide in substrate application range, suitable for carbon-carbon double bonds,carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogen triple bonds and epoxy functional groups, good in selectivity and high in reaction specificity.
Generalized Chemoselective Transfer Hydrogenation/Hydrodeuteration
Wang, Yong,Cao, Xinyi,Zhao, Leyao,Pi, Chao,Ji, Jingfei,Cui, Xiuling,Wu, Yangjie
supporting information, p. 4119 - 4129 (2020/08/10)
A generalized, simple and efficient transfer hydrogenation of unsaturated bonds has been developed using HBPin and various proton reagents as hydrogen sources. The substrates, including alkenes, alkynes, aromatic heterocycles, aldehydes, ketones, imines, azo, nitro, epoxy and nitrile compounds, are all applied to this catalytic system. Various groups, which cannot survive under the Pd/C/H2 combination, are tolerated. The activity of the reactants was studied and the trends are as follows: styrene'diphenylmethanimine'benzaldehyde'azobenzene'nitrobenzene'quinoline'acetophenone'benzonitrile. Substrates bearing two or more different unsaturated bonds were also investigated and transfer hydrogenation occurred with excellent chemoselectivity. Nano-palladium catalyst in situ generated from Pd(OAc)2 and HBPin extremely improved the TH efficiency. Furthermore, chemoselective anti-Markovnikov hydrodeuteration of terminal aromatic olefins was achieved using D2O and HBPin via in situ HD generation and discrimination. (Figure presented.).
Intramolecular activation of imidate with cationic gold(I) catalyst: A new benzylation reaction of alcohols
Ban, Shintaro,Endo, Tomotake,Matsui, Rikako,Morita, Nobuyoshi,Hashimoto, Yoshimitsu,Tanaka, Kosaku,Tamura, Osamu
, (2020/08/28)
Benzylation of alcohols with benzyl (Z)-2,2,2-trifluoro-N-(2-alkynylphenyl)acetimidates 5a-f in the presence of a cationic gold(I) catalyst was investigated. Reagent 5f was the most effective, affording benzyl ethers in good yields. Our results indicate that these gold(I)-activated imidates are effective leaving groups.
p-Methylbenzyl 2,2,2-Trichloroacetimidate: Simple Preparation and Application to Alcohol Protection
Arai, Tomoki,Ikeuchi, Kazutada,Murasawa, Kentaro,Yamada, Hidetsohi
supporting information, p. 1034 - 1037 (2020/09/16)
A method for p-methylbenzyl (MBn) protection of alcohols by using MBn 2,2,2-trichloroacetimidate is described. The trichloroacetimidate can easily be prepared and isolated as a stable white powder without purification by silica gel chromatography. Catalytic use of zinc(II) triflate in diethyl ether activates the trichloroacetimidate to enable MBn protection of various alcohols.
Superior activity and selectivity of multifunctional catalyst Pd-DTP@ZIF-8 in one pot synthesis of 3-phenyl propyl benzoate
Malkar, Radhika S.,Yadav, Ganapati D.
, p. 282 - 293 (2019/04/01)
The catalytic efficiency of zeolitic imidazolate framework (ZIF-8) has been explored by making it multifunctional. Dual active sites were incorporated such as acid (dodecatungstophosphoric acid, DTP) and metal (Pd°) to prepare 5% Pd-DTP@ZIF-8. DTP was encapsulated inside the cage of ZIF-8 by in-situ and bottle around the ship approach whereas Pd was loaded ex-situ by simple wet impregnation method. The catalytic efficiency was tested for one pot synthesis of 3-phenyl propyl benzoate (3-PPB), a perfumery compound, from cinnamyl alcohol and benzoic anhydride. Trans-esterification of cinnamyl alcohol with benzoic anhydride gives cinnamyl benzoate which on further hydrogenation gives 3-PPB. Three different supports were screened such as ZIF-8, K10 and MCF out of which ZIF-8 showed the maximum activity because of its high surface area and smaller pore diameter. Further Pd, Ni and Cu metals were studied for selective hydrogenation of C[dbnd]C bond among which 5% Pd-DTP@ZIF-8 gave almost 98% conversion of cinnamyl benzoate to 3-PPB with 93% selectivity. Fresh and spent catalysts were characterized by various techniques. 5% Pd-DTP@ZIF-8 showed anti-leaching property with great thermal stability. The turn over frequency and turn over number of the catalyst was observed to be 0.058 s?1 and 835, respectively. A kinetic model was developed with good fit using LHHW mechanism and the activation energy calculated as 17.45 kcal/mol for hydrogenation step. Thus, the reaction was found to be kinetically controlled. The entire process is green.
Preparation of Alkyl Ethers with Diallyltriazinedione-Type Alkylating Agents (ATTACKs-R) Under Acid Catalysis
Fujita, Hikaru,Yamashita, Rina,Fujii, Takanori,Yamada, Kohei,Kitamura, Masanori,Kunishima, Munetaka
, p. 4436 - 4446 (2019/07/03)
Diallyltriazinedione-type acid-catalyzed alkylating agents (ATTACKs-R) with 10 different alkyl groups (R), including benzyl, substituted benzyl, allyl, and methyl groups were synthesized. The palladium-catalyzed intramolecular O-to-N allylic rearrangement of 2,4-bis(allyloxy)-6-chloro-1,3,5-triazine was developed to introduce various alkoxy groups into the N,N′-dialkylated triazinedione skeleton. O-Alkylation of alcohols with ATTACKs-R was carried out in 1,4-dioxane in the presence of 2,6-di-tert-butylpyridinium trifluoromethanesulfonate or trifluoromethanesulfonic acid as a catalyst. Six selected ATTACKs-R bearing benzylic R groups were employed to prepare alkyl ethers from primary, secondary, and tertiary alcohols. The reactions of ATTACKs-R bearing an o-nitro-substituted benzyl group tended to afford low yields. Comparison of four different triazinedione-based benzylating reagents suggested that the N,N′-substituents affected the reactivity.
Specific Inhibition of the Hydrogenolysis of Benzylic C?O Bonds Using Palladium Nanoparticles Supported on Nitrogen-Doped Carbon Nanofibers
Motoyama, Yukihiro,Morii, Koshi,Ishizuka, Shoya,Inomoto, Sou,Zhang, Zhenzhong,Yoon, Seong-Ho
, p. 505 - 509 (2018/02/15)
Palladium nanoparticles supported on 5 %-nitrogen-doped, herringbone-type carbon nanofibers (Pd/N-CNF-H), which are prepared by thermally decomposing [Pd2(dba)3?CHCl3] (dba=dibenzylideneacetone) in toluene in the presence of N-CNF-H, were found to be an efficient catalyst for the chemoselective hydrogenation of alkenyl and nitro moieties in benzyl-protected alcohols and carboxylic acid derivatives with high turnover frequencies: the hydrogenation reactions of these functional groups proceeded smoothly even at ambient temperature under atmospheric H2 pressure, and the benzyl protecting groups in the molecules remained intact. Moreover, the recovered Pd/N-CNF-H catalyst could be reused without loss of its catalytic activity or chemoselectivity. The Pd/N-CNF-H catalyst also acted as an effective hydrogenation catalyst for the reduction of aromatic ketones to the corresponding benzyl alcohol derivatives with good to high product selectivity.
Cooperation of the Neutral and the Cationic Leaving Group Pathways in Acid-Catalyzed O-Benzylation of TriBOT
Fujita, Hikaru,Hayakawa, Naoko,Kunishima, Munetaka
, p. 10684 - 10687 (2018/07/25)
The reaction profile of acid-catalyzed O-benzylation with 2,4,6-tris(benzyloxy)-1,3,5-triazine (TriBOT) was analyzed to study the reaction kinetics. The first-order kinetic constant for the formation of benzyl cation species from N-protonated TriBOT (neutral leaving group pathway) was estimated and compared with that of the model compound for TriBOT. Since rapid consumption of TriBOT in the late stage could not be explained solely by this pathway, cooperation of another reaction mechanism, the cationic leaving group pathway, was proposed to rationalize the rate acceleration.
