5789-31-1Relevant academic research and scientific papers
Ruthenium-Catalyzed Dehydrogenation Through an Intermolecular Hydrogen Atom Transfer Mechanism
Huang, Lin,Bismuto, Alessandro,Rath, Simon A.,Trapp, Nils,Morandi, Bill
supporting information, p. 7290 - 7296 (2021/03/01)
The direct dehydrogenation of alkanes is among the most efficient ways to access valuable alkene products. Although several catalysts have been designed to promote this transformation, they have unfortunately found limited applications in fine chemical synthesis. Here, we report a conceptually novel strategy for the catalytic, intermolecular dehydrogenation of alkanes using a ruthenium catalyst. The combination of a redox-active ligand and a sterically hindered aryl radical intermediate has unleashed this novel strategy. Importantly, mechanistic investigations have been performed to provide a conceptual framework for the further development of this new catalytic dehydrogenation system.
Nickel-catalyzed migratory alkyl-alkyl cross-coupling reaction
Li, Yangyang,Li, Yuqiang,Peng, Long,Wu, Dong,Yin, Guoyin,Zhu, Lei
, p. 10461 - 10464 (2020/10/18)
The selective cross-coupling of activated electrophiles with unactivated ones has been regarded as a challenging task in cross-electrophile couplings. Herein we describe a migratory cross-coupling strategy, which can overcome this obstacle to access the desired cross-coupling products. Accordingly, a selective migratory cross-coupling of two alkyl electrophiles has been accomplished by nickel catalysis. Remarkably, this alkyl-alkyl cross-coupling reaction provides a platform to prepare 2°-2° carbon-carbon bonds from 1° and 2° carbon coupling partners. Preliminary mechanistic studies suggest that chain-walking occurs at both alkyl halides in this reaction, thus a catalytic cycle with the key step involving two alkylnickel(ii) species is proposed for this transformation.
Asymmetric Hydrogenation of Unfunctionalized Tetrasubstituted Acyclic Olefins
Bachmann, Stephan,Bigler, Raphael,Denmark, Scott E.,Gosselin, Francis,Han, Chong,Hildbrand, Stefan,Mack, Kyle A.,Pfaltz, Andreas,Scalone, Michelangelo,Shen, Jeff,Tosatti, Paolo,Zhang, Haiming
supporting information, p. 2844 - 2849 (2020/02/05)
Asymmetric hydrogenation has evolved as one of the most powerful tools to construct stereocenters. However, the asymmetric hydrogenation of unfunctionalized tetrasubstituted acyclic olefins remains the pinnacle of asymmetric synthesis and an unsolved challenge. We report herein the discovery of an iridium catalyst for the first, generally applicable, highly enantio- and diastereoselective hydrogenation of such olefins and the mechanistic insights of the reaction. The power of this chemistry is demonstrated by the successful hydrogenation of a wide variety of electronically and sterically diverse olefins in excellent yield and high enantio- and diastereoselectivity.
Copper(II)-Photocatalyzed N-H Alkylation with Alkanes
Donabauer, Karsten,K?nig, Burkhard,Narobe, Rok,Yakubov, Shahboz,Zheng, Yi-Wen
, p. 8582 - 8589 (2020/09/23)
We report a practical method for the alkylation of N-H bonds with alkanes using a photoinduced copper(II) peroxide catalytic system. Upon light irradiation, the peroxide serves as a hydrogen atom transfer reagent to activate stable C(sp3)-H bonds for the reaction with a broad range of nitrogen nucleophiles. The method enables the chemoselective alkylation of amides and is utilized for the late-stage functionalization of N-H bond containing pharmaceuticals with good to excellent yields. The mechanism of the reaction was preliminarily investigated by radical trapping experiments and spectroscopic methods.
Luminescent tungsten(vi) complexes as photocatalysts for light-driven C-C and C-B bond formation reactions
Chan, Kaai-Tung,Che, Chi-Ming,Du, Lili,Liu, Yungen,Phillips, David Lee,To, Wai-Pong,Tong, Glenna So Ming,Wu, Liang-Liang,Yu, Daohong
, p. 6370 - 6382 (2020/07/15)
The realization of photocatalysis for practical synthetic application hinges on the development of inexpensive photocatalysts which can be prepared on a large scale. Herein an air-stable, visible-light-absorbing photoluminescent tungsten(vi) complex which can be conveniently prepared at the gram-scale is described. This complex could catalyse photochemical organic transformation reactions including borylation of aryl halides, such as aryl chloride, reductive coupling of benzyl bromides for C-C bond formation, reductive coupling of phenacyl bromides, and decarboxylative coupling of redox-active esters of alkyl carboxylic acid with high product yields and broad functional group tolerance.
3-Acetoxyquinuclidine as Catalyst in Electron Donor-Acceptor Complex-Mediated Reactions Triggered by Visible Light
Bosque, Irene,Bach, Thorsten
, p. 9103 - 9109 (2019/10/16)
3-Acetoxyquinuclidine was found to act as a catalytic electron donor species in a variety of electron donor-acceptor complex-mediated reactions. Only substoichiometric amounts (10-25 mol %) were needed to trigger the desired reaction. The outcome could be tuned by selecting the nature of the formed radical to perform amino- and hydro-decarboxylation, dimerization, and cyclization reactions. Importantly, no external additives were needed in this reaction.
Correction to: Nickel-catalyzed asymmetric reductive cross-coupling to access 1,1-diarylalkanes (Journal of the American Chemical Society (2017) 139 (5684-5687) DOI: 10.1021/jacs.7b01705)
Poremba, Kelsey E.,Kadunce, Nathaniel T.,Suzuki, Naoyuki,Cherney, Alan H.,Reisman, Sarah E.
supporting information, p. 7746 - 7746 (2018/06/26)
Pages 5684 and 5685, Table of Contents, and Supporting Information. The stereochemistry of L1, depicted as the (S,S)- enantiomer in Figure 1, Table 1, the TOC graphic (identical to Figure 1), and the Supporting Information of the original publication, was incorrect. (R,R)-L1 was used in this study. The stereochemistry of (R,R)-L1 has been confirmed by singlecrystal X-ray diffraction; the X-ray diffraction data and CIF file for (R,R)-L1 have been added to the Supporting Information. The corrected TOC graphic/Figure 1 is shown here. (R,R)-L4 and (R,R)-L5 were also used in Table 1 and incorrectly depicted as (S,S)-L4 and (S,S)-L5 in the original publication. To reflect that different enantiomeric series of catalysts were used, Table 1 has been updated to indicate that entries 2, 3, and 6 produce (S)-3a. This correction does not change the stereochemical assignment of the diarylalkane products, or the conclusions of the Communication. The stereochemistry of the products was assigned by obtaining an X-ray structure of diarylalkane 3k, and the rest of the compounds were assigned by analogy. (Table Presented).
Nondirecting Group sp3 C?H Activation for Synthesis of Bibenzyls via Homo-coupling as Catalyzed by Reduced Graphene Oxide Supported PtPd@Pt Porous Nanospheres
Wang, Zheng-Jun,Lv, Jing-Jing,Yi, Rong-Nan,Xiao, Min,Feng, Jiu-Ju,Liang, Zhi-Wu,Wang, Ai-Jun,Xu, Xinhua
supporting information, p. 932 - 941 (2018/01/05)
The use of heterogeneous bimetallic Pd-based nanocatalyst for directing the inactivated sp3 C?H coupling has been scarcely explored. This work reported the formation of symmetrical C?C bonds from the inactivated sp3 C?H bonds catalyzed by employing reduced graphene oxide supported PtPd@Pt porous nanospheres. The reaction of sp3 C?H activation proceeded under mild conditions without any solvent, ligand or directing group. It is a higher atom-, step- and cost-effectiveness strategy for developing heterogeneous catalysts in the synthesis of bibenzyls with various functional groups (e. g. aryl, alkyl, methoxyl, halogen, ester, and pyridyl). (Figure presented.).
Method for synthesizing 1,2-diphenylethane derivative by catalyzing coupling of sp3C-H bond through graphene-loaded palladium/platinum
-
Paragraph 0019; 0020, (2018/07/15)
The invention provides a novel method for catalyzing activation of an sp3C-H bond to build a 1,2-diphenylethane compound by developing a novel graphene-loaded bimetal palladium/platinum catalyst whichis simple, convenient and efficient, is free of guide groups and free of participation of solvents and can be reused, so as to increase the yield of the target product, simplify operation steps and improve an atom utilization ratio and the recovery of the catalyst. The invention provides an economical, efficient and green method for preparing the compound. The method has the main advantages thatexperiment operation is simple and convenient, guide groups are not needed, the participation of other solvents is not needed, and the catalyst can be repeatedly recycled.
Nickel-Catalyzed Asymmetric Reductive Cross-Coupling to Access 1,1-Diarylalkanes
Poremba, Kelsey E.,Kadunce, Nathaniel T.,Suzuki, Naoyuki,Cherney, Alan H.,Reisman, Sarah E.
, p. 5684 - 5687 (2017/05/04)
An asymmetric Ni-catalyzed reductive cross-coupling of (hetero)aryl iodides and benzylic chlorides has been developed to prepare enantioenriched 1,1-diarylalkanes. As part of these studies, a new chiral bioxazoline ligand, 4-heptyl-BiOX (L1), was developed in order to obtain products in synthetically useful yield and enantioselectivity. The reaction tolerates a variety of heterocyclic coupling partners, including pyridines, pyrimidines, indoles, and piperidines.
