40851-62-5Relevant academic research and scientific papers
Insertion of Diazo Esters into C-F Bonds toward Diastereoselective One-Carbon Elongation of Benzylic Fluorides: Unprecedented BF3Catalysis with C-F Bond Cleavage and Re-formation
Wang, Fei,Nishimoto, Yoshihiro,Yasuda, Makoto
supporting information, p. 20616 - 20621 (2021/11/23)
Selective transformation of C-F bonds remains a significant goal in organic chemistry, but C-F insertion of a one-carbon-atom unit has never been established. Herein we report the BF3-catalyzed formal insertion of diazo esters as one-carbon-atom sources into C-F bonds to accomplish one-carbon elongation of benzylic fluorides. A DFT calculation study revealed that the BF3 catalyst could contribute to both C-F bond cleavage and re-formation. This elongation provided α-fluoro-α,β-diaryl esters with a high level of diastereoselectivity. Various benzylic fluorides and diazo esters were applicable. The synthetic utility of this method was demonstrated by the synthesis of a fluoro analogue of a compound that is used as a transient receptor and potential canonical channel inhibitor.
Electrochemical oxidative: Z -selective C(sp2)-H chlorination of acrylamides
Coles, Simon J.,Hareram, Mishra Deepak,Harnedy, James,Morrill, Louis C.,Tizzard, Graham J.
supporting information, p. 12643 - 12646 (2021/12/07)
An electrochemical method for the oxidative Z-selective C(sp2)-H chlorination of acrylamides has been developed. This catalyst and organic oxidant free method is applicable across various substituted tertiary acrylamides, and provides access to a broad range of synthetically useful Z-β-chloroacrylamides in good yields (22 examples, 73% average yield). The orthogonal derivatization of the products was demonstrated through chemoselective transformations and the electrochemical process was performed on gram scale in flow.
3,3′-Disubstituted Oxindoles Formation via Copper-Catalyzed Arylboration and Arylsilylation of Alkenes
Liang, Ren-Xiao,Chen, Ru-Yi,Zhong, Chao,Zhu, Jia-Wen,Cao, Zhong-Yan,Jia, Yi-Xia
supporting information, p. 3215 - 3218 (2020/04/10)
Arylboration and arylsilylation reactions of N-(2-iodoaryl)acrylamides with bis(pinacolato)-diboron (B2pin2) or PhMe2Si-Bpin are developed by using simple CuOAc as the sole catalyst. A range of boron-or silane-bearing 3,3′-disubstituted oxindoles are obtained in moderate to excellent yields. The reaction is proposed to proceed via a domino sequence involving intermolecular olefin borylcupration or silylcupration followed by intramolecular coupling of an alkyl-Cu intermediate with aryl iodide.
Pd-Catalyzed Decarboxylative Olefination: Stereoselective Synthesis of Polysubstituted Butadienes and Macrocyclic P-glycoprotein Inhibitors
Chen, Xiangyang,Hao, Jiping,Houk, K. N.,Li, Yingzi,Lou, Liguang,Quan, Haitian,Song, Bichao,Wang, Lu,Xia, Yuanzhi,Xie, Peipei,Xu, Zhongliang,Yang, Weibo
supporting information, p. 9982 - 9992 (2020/06/27)
The efficient and stereoselective synthesis of polysubstituted butadienes, especially the multifunctional butadienes, represents a great challenge in organic synthesis. Herein, we wish to report a distinctive Pd(0) carbene-initiated decarboxylative olefination approach that enables the direct coupling of diazo esters with vinylethylene carbonates (VECs), vinyl oxazolidinones, or vinyl benzoxazinones to afford alcohol-, amine-, or aniline-containing 1,3-dienes in moderate to high yields and with excellent stereoselectivity. This protocol features operational simplicity, mild reaction conditions, a broad substrate scope, and gram-scalability. Notably, a structurally unique allylic Pd(II) intermediate was isolated and characterized. DFT calculation and control experiments demonstrated that a rare Pd(0) carbene intermediate could be involved in this reaction. Moreover, the polysubstituted butadienes as novel building blocks were unprecedentedly assembled into macrocycles, which efficiently inhibited the P-glycoprotein and dramatically reversed multidrug resistance in cancer cells by 190-fold.
Photocatalytic Hydromethylation and Hydroalkylation of Olefins Enabled by Titanium Dioxide Mediated Decarboxylation
Zhu, Qilei,Nocera, Daniel G.
supporting information, p. 17913 - 17918 (2020/12/04)
A versatile method for the hydromethylation and hydroalkylation of alkenes at room temperature is achieved by using the photooxidative redox capacity of the valence band of anatase titanium dioxide (TiO2). Mechanistic studies support a radical-based mechanism involving the photoexcitation of TiO2 with 390 nm light in the presence of acetic acid and other carboxylic acids to generate methyl and alkyl radicals, respectively, without the need for stoichiometric base. This protocol is accepting of a broad scope of alkene and carboxylic acids, including challenging ones that produce highly reactive primary alkyl radicals and those containing functional groups that are susceptible to nucleophilic substitution such as alkyl halides. This methodology highlights the utility of using heterogeneous semiconductor photocatalysts such as TiO2 for promoting challenging organic syntheses that rely on highly reactive intermediates.
Dehydroxymethylation of alcohols enabled by cerium photocatalysis
Zhang, Kaining,Chang, Liang,An, Qing,Wang, Xin,Zuo, Zhiwei
supporting information, p. 10556 - 10564 (2019/08/20)
Dehydroxymethylation, the direct conversion of alcohol feedstocks as alkyl synthons containing one less carbon atom, is an unconventional and underexplored strategy to exploit the ubiquity and robustness of alcohol materials. Under mild and redox-neutral reaction conditions, utilizing inexpensive cerium catalyst, the photocatalytic dehydroxymethylation platform has been furnished. Enabled by ligand-to-metal charge transfer catalysis, an alcohol functionality has been reliably transferred into nucleophilic radicals with the loss of one molecule of formaldehyde. Intriguingly, we found that the dehydroxymethylation process can be significantly promoted by the cerium catalyst, and the stabilization effect of the fragmented radicals also plays a significant role. This operationally simple protocol has enabled the direct utilization of primary alcohols as unconventional alkyl nucleophiles for radical-mediated 1,4-conjugate additions with Michael acceptors. A broad range of alcohols, from simple ethanol to complex nucleosides and steroids, have been successfully applied to this fragment coupling transformation. Furthermore, the modularity of this catalytic system has been demonstrated in diversified radical-mediated transformations including hydrogenation, amination, alkenylation, and oxidation.
Dehydroxymethylation of Alcohols Enabled by Cerium Photocatalysis
Zhang, Kaining,Chang, Liang,An, Qing,Wang, Xin,Zuo, Zhiwei
supporting information, p. 10556 - 10564 (2019/08/28)
Dehydroxymethylation, the direct conversion of alcohol feedstocks as alkyl synthons containing one less carbon atom, is an unconventional and underexplored strategy to exploit the ubiquity and robustness of alcohol materials. Under mild and redox-neutral reaction conditions, utilizing inexpensive cerium catalyst, the photocatalytic dehydroxymethylation platform has been furnished. Enabled by ligand-to-metal charge transfer catalysis, an alcohol functionality has been reliably transferred into nucleophilic radicals with the loss of one molecule of formaldehyde. Intriguingly, we found that the dehydroxymethylation process can be significantly promoted by the cerium catalyst, and the stabilization effect of the fragmented radicals also plays a significant role. This operationally simple protocol has enabled the direct utilization of primary alcohols as unconventional alkyl nucleophiles for radical-mediated 1,4-conjugate additions with Michael acceptors. A broad range of alcohols, from simple ethanol to complex nucleosides and steroids, have been successfully applied to this fragment coupling transformation. Furthermore, the modularity of this catalytic system has been demonstrated in diversified radical-mediated transformations including hydrogenation, amination, alkenylation, and oxidation.
Iridium-Catalyzed α-Methylation of α-Aryl Esters Using Methanol as the C1 Source
Tsukamoto, Yuya,Itoh, Satoshi,Kobayashi, Masaki,Obora, Yasushi
supporting information, p. 3299 - 3303 (2019/05/10)
IrCl(cod)2]/dppe-catalyzed α-methylation of aryl esters using methanol as the C1 source was developed. This methylation process is useful in several fields including organic chemistry, biochemistry, and medicinal chemistry. Readily available methanol as methylation reagent was successfully adapted. The reaction processed high atom economy and efficient. By applying the reaction system, the synthesis method of naproxen was provided.
Synthesis and bio-evaluation of natural butenolides-acrylate conjugates
Bao, Longzhu,Wang, Shuangshuang,Song, Di,Wang, Jingjing,Cao, Xiufang,Ke, Shaoyong
, (2019/04/05)
A series of novel 3-aryl-4-hydroxy-2(5H) furanone-acrylate hybrids were designed and synthesized based on the natural butenolides and acrylates scaffolds. The structures of the prepared compounds were characterized by 1H-NMR, 13C-NMR and electrospray ionization mass spectrometry (ESI-MS), and the bioactivity of the target compounds against twelve phytopathogenic fungi was investigated. The preliminary in vitro antifungal activity screening showed that most of the target compounds had moderate inhibition on various pathogenic fungi at the concentration of 100 mg·L?1, and presented broad-spectrum antifungal activities. Further studies also indicated that compounds 7e and 7k still showed some inhibitory activity against Pestallozzia theae, Sclerotinia sclerotiorum and Gibberella zeae on rape plants at lower concentrations, which could be optimized as a secondary lead for further research.
Palladium-Catalyzed C?H Silylation through Palladacycles Generated from Aryl Halides
Lu, Ailan,Ji, Xiaoming,Zhou, Bo,Wu, Zhuo,Zhang, Yanghui
supporting information, p. 3233 - 3237 (2018/02/23)
A highly efficient palladium-catalyzed disilylation reaction of aryl halides through C?H activation has been developed for the first time. The reaction has broad substrate scope. A variety of aryl halides can be disilylated by three types of C?H activation, including C(sp2)?H, C(sp3)?H, and remote C?H activation. In particular, the reactions are also unusually efficient. The yields are essentially quantitative in many cases, even in the presence of less than 1 mol % catalyst and 1 equivalent of the silylating reagent under relatively mild conditions. The disilylated biphenyls can be converted into disiloxane-bridged biphenyls.
