- Visible Light-Promoted Recyclable Carbon Nitride-Catalyzed Dioxygenation of β,γ-Unsaturated Oximes
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A visible-light-induced dioxygenation of β,γ-unsaturated oximes for the synthesis of diverse useful isoxazolines bearing a hydroxyl moiety was developed by employing graphitic carbon nitride (g-C3N4) as a heterogeneous photocatalyst under an air atmosphere. Noted that, the eminent advantages of this metal-free protocol include step economy, easy operation, a recyclable photocatalyst, external reductant-/oxidant-free and mild reaction conditions. Additionally, mechanistic studies indicated hydroxyl radical was generated under the photocatalysis of g-C3N4.
- Fu, Xiao-Yang,Si, Ya-Feng,Qiao, Li-Peng,Zhao, Yu-Fen,Chen, Xiao-Lan,Yu, Bing
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supporting information
p. 574 - 580
(2021/11/13)
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- Organocatalytic Asymmetric Synthesis of Cyclic Acetals with Spirooxindole Skeleton
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An organocatalytic asymmetric synthesis of cyclic acetal with spirooxindole skeleton has been developed via a domino reaction between isatin and γ-hydroxy enones. Bifunctional squaramide catalyst with adamantyl motif was found to be the most effective for the cascade reaction. With 10 mol% of the catalyst, the desired products were obtained in 1.8:1 to 9:1 diastereo- and 86% to >99% enantioselectivities from a range of substituted isatins and γ-hydroxy enones. (Figure presented.).
- Shikari, Amit,Mandal, Koushik,Chopra, Deepak,Pan, Subhas Chandra
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supporting information
p. 58 - 63
(2021/11/09)
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- Copper-catalyzed radical oxyallylation of olefins for the construction of alkene-containing isoxazolines
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A radical-mediated approach to alkene oxyallylation using allylic oximes is described. The reaction proceeds under copper-catalytic redox-neutral conditions and tolerates various functional groups. This protocol thus enables the synthesis of structurally valuable isoxazolines and the introduction of a versatile olefin motif in a single step.
- He, Xiaoxue,Qian, Lijie,Dai, Yuyu,Yan, Xinhuan,Li, Xiaoqing,Xu, Xiangsheng
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supporting information
(2021/05/31)
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- Ni-Catalyzed 1,2-Diarylation of Alkenyl Ketones: A Comparative Study of Carbonyl-Directed Reaction Systems
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A nickel-catalyzed 1,2-diarylation of alkenyl ketones with aryl iodides and arylboronic esters is reported. Ketones with a variety of substituents serve as effective directing groups, offering high levels of regiocontrol. A representative product is diversified into a wide range of useful products that are not readily accessible via existing 1,2-diarylation reactions. Preliminary mechanistic studies shed light on the binding mode of the substrate, and Hammett analysis reveals the effect of electronic factors on initial rates.
- Apolinar, Omar,Derosa, Joseph,Engle, Keary M.,Karunananda, Malkanthi K.,Kleinmans, Roman,Li, Zi-Qi,Tran, Van T.,Wisniewski, Steven R.
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supporting information
p. 5311 - 5316
(2021/07/26)
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- Photoinduced Olefin Diamination with Alkylamines
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Vicinal diamines are ubiquitous materials in organic and medicinal chemistry. The direct coupling of olefins and amines would be an ideal approach to construct these motifs. However, alkene diamination remains a long-standing challenge in organic synthesis, especially when using two different amine components. We report a general strategy for the direct and selective assembly of vicinal 1,2-diamines using readily available olefin and amine building blocks. This mild and straightforward approach involves in situ formation and photoinduced activation of N-chloroamines to give aminium radicals that enable efficient alkene aminochlorination. Owing to the ambiphilic nature of the β-chloroamines produced, conversion into tetra-alkyl aziridinium ions was possible, thus enabling diamination by regioselective ring-opening with primary or secondary amines. This strategy streamlines the preparation of vicinal diamines from multistep sequences to a single chemical transformation.
- Angelini, Lucrezia,Govaerts, Sebastian,Hampton, Charlotte,Leonori, Daniele,Malet-Sanz, Laia,Ruffoni, Alessandro
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supporting information
p. 15021 - 15028
(2020/06/17)
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- Electrochemical Chalcogenation of β,γ-Unsaturated Amides and Oximes to Corresponding Oxazolines and Isoxazolines
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The current report represents a transition-metal-free synthesis of oxazoline and isoxazoline derivatives by a tandem electro-oxidative chalcogenation-cyclization process. Both C?Se and C?S bond-forming protocols were developed without using any external oxidant and the reaction was performed at room temperature, open to the air. Using this methodology, 29 substituted oxazoline and 16 substituted isoxazoline derivatives were synthesized with up to 91% isolated yield. (Figure presented.).
- Baidya, Mrinmay,De Sarkar, Suman,Mahanty, Kingshuk,Maiti, Debabrata,Mallick, Samrat
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supporting information
(2020/02/04)
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- Enantioselective Synthesis of Isoxazolines Enabled by Palladium-Catalyzed Carboetherification of Alkenyl Oximes
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Reported here is a highly efficient Pd/Xiang-Phos catalyzed enantioselective carboetherification of alkenyl oximes with either aryl or alkenyl halides, delivering various chiral 3,5-disubstituted and 3,5,5-trisubstituted isoxazolines in good yields with u
- Chen, Mingjie,Li, Wenbo,Wang, Lei,Wang, Yuzhuo,Zhang, Junliang,Zhang, Kenan
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supporting information
p. 4421 - 4427
(2020/02/11)
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- Copper-catalyzed asymmetric cyanation of alkenes via carbonyl-assisted coupling of alkyl-substituted carbon-centered radicals
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Based on a copper-catalyzed radical relay strategy, the first copper-catalyzed asymmetric cyanation of alkyl-substituted alkenes has been developed. The reaction, featuring mild reaction conditions and excellent functional group compatibilities, provides
- Zhou, Song,Zhang, Guoyu,Fu, Liang,Chen, Pinhong,Li, Yibiao,Liu, Guosheng
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supporting information
p. 6299 - 6303
(2020/10/02)
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- Copper-Catalyzed Aerobic Cyclization of β,γ-Unsaturated Hydrazones with Concomitant CC Bond Cleavage
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A Cu-catalyzed aerobic oxidative cyclization of β,γ-unsaturated hydrazones for the preparation of pyrazole derivatives has been developed. The hydrazonyl radical promoted the cyclization, along with a concomitant CC bond cleavage of β,γ-unsaturated hydrazones. This process has been verified via several control experiments, including a radical-trapping study, an 18O-labeling method, and the identification of the possible byproducts. The advantages of this reaction include operational simplicity, a broad reaction scope, and a mild selective reaction process.
- Fan, Zhenwei,Feng, Jiahao,Hou, Yuchen,Rao, Min,Cheng, Jiajia
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supporting information
p. 7981 - 7985
(2020/11/02)
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- Copper-Promoted 6- endo-trig Cyclization of β,γ-Unsaturated Hydrazones for the Synthesis of 1,6-Dihydropyridazines
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A novel and efficient strategy for the synthesis of 1,6-dihydropyridazines via copper-promoted 6-endo-trig cyclization of readily available β,γ-unsaturated hydrazones have been developed. A series of 1,6-dihydropyridazines have been synthesized by this method with good yields, high functional group tolerance, and remarkable regioselectivity under mild conditions. Importantly, the 1,6-dihydropyridazines can be efficiently converted to biologically important pyridazines in the presence of NaOH.
- Guo, Yong-Qiang,Zhao, Mi-Na,Ren, Zhi-Hui,Guan, Zheng-Hui
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supporting information
p. 3337 - 3340
(2018/06/11)
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- Ruthenium-Catalyzed Direct Transformation of Alkenyl Oximes to 5-Cyanated Isoxazolines: A Cascade Approach Based on Non-Stabilized Radical Intermediate
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A ruthenium-catalyzed ammoxidation of alkenyl oximes under mild and neutural condtions is described. In this method, tert-butyl nitrite plays a dual role, acting as an oxidant as well as a nitrogen source. This reaction avoids using any toxic radical initiators or cyanide reagents. This convenient and practical method offers an easy access to 5-cyanated isoxazolines in good to high yields, and shows good functional group tolerance and high efficiency. It is rather remarkable that this new reaction provides a strategically distinct approach based on non-stabilized radical intermediate and constructs C–O and C≡N triple bonds in a single-step. Moreover, the difunctionalization of unactivated olefins bearing oximes has been realized.
- Wang, Dan-Jun,Chen, Bei-Yi,Wang, Yi-Qi,Zhang, Xiao-Wei
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supporting information
p. 1342 - 1346
(2018/04/02)
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- Catalyst-Controlled Diastereoselective Synthesis of Cyclic Amines via C-H Functionalization
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Reliable regio- and stereochemical techniques applicable to nonactivated aliphatic systems remain largely elusive due to the challenges of discriminating between multiple, relatively strong sp3 C-H bonds whose chemical behavior often differ onl
- Munnuri, Sailu,Adebesin, Adeniyi Michael,Paudyal, Mahesh P.,Yousufuddin, Muhammed,Dalipe, Alfonso,Falck, John R.
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supporting information
p. 18288 - 18294
(2017/12/27)
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- Green organocatalytic synthesis of isoxazolines via a one-pot oxidation of allyloximes
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A green, sustainable, organocatalytic, and efficient synthesis of isoxazolines from allyloximes was developed. A 2,2,2-trifluoroacetophenone-catalyzed oxidation of allyloximes, utilizing H2O2 as the green oxidant, was taken advantage of in order to introduce a cheap and environmentally friendly protocol for the synthesis of substituted isoxazolines. A variety of substitution patterns, both aromatic and aliphatic moieties, are well tolerated, leading to isoxazolines in moderate to excellent yields.
- Triandafillidi, Ierasia,Kokotos, Christoforos G.
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supporting information
p. 106 - 109
(2017/11/27)
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- Lewis Acid Catalyzed [3+3] Annulation of Donor–Acceptor Cyclopropanes with γ-Hydroxyenones: Access to Highly Functionalized Tetrahydropyrans
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Donor–acceptor cyclopropanes were engaged in a [3+3]-annulation reaction with γ-hydroxyenones. Sc(OTf)3was found to be the best catalyst, and 2,4,4,5-tetrasubstituted tetrahydropyran products were obtained in good yields under mild reaction con
- Mondal, Keshab,Pan, Subhas Chandra
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supporting information
p. 534 - 537
(2017/02/05)
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- Metal-Free Autoxidative Nitrooxylation of Alkenyl Oximes with Molecular Oxygen
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A metal-free aerobic autoxidative nitrooxylation of alkenyl oximes mediated by tert-butyl nitrite is described. Molecular oxygen is used as the oxidizing reagent, avoiding use of organic trapping reagents such as 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMP
- Zhang, Xiao-Wei,Xiao, Zu-Feng,Zhuang, Yan-Jun,Wang, Mei-Mei,Kang, Yan-Biao
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supporting information
p. 1942 - 1945
(2016/07/06)
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- Palladium(0)-mediated cyclization-coupling of β,γ-unsaturated oximes and aryl iodides
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The tandem palladium(0)-mediated nucleometalation-cross coupling of β,γ-unsaturated oximes with aryl iodides has been shown to provide the expected 3,5-disubstituted 2-isoxazolines in acceptable yields (11-78%). The addition of a weak base is required for product formation. Some influence on the yield of the reaction is noted in the electronic character of the aryl iodide used in the reaction. Exploration of the substitution patterns on the reactants has led to a proposed mechanism involving a palladium(II)-catalyzed nucleometalation/cyclization followed by reductive elimination of palladium(0) with concomitant coupling to an arene.
- Mikesell, Joshua,Mosher, Michael D.
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p. 1011 - 1013
(2016/02/16)
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- Organocatalytic Redox Isomerization of Electron-Deficient Allylic Alcohols: Synthesis of 1,4-Ketoaldehydes
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An organocatalytic redox isomerization strategy has been developed for the synthesis of 1,4-ketoaldehydes. DABCO was found to be the best catalyst for the isomerization of -hydroxy enones. With 20 mol % of DABCO as catalyst and DMSO as the solvent high yi
- Mondal, Keshab,Mondal, Buddhadeb,Pan, Subhas Chandra
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p. 4835 - 4840
(2016/07/06)
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- Transition-metal-free oxychlorination of alkenyl oximes:: In situ generated radicals with tert -butyl nitrite
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Oxychlorination of alkenyl oximes is harder compared to the analogous oxybromination or oxyiodination because of the difficulty associated with the formation of chlorine cations or radicals. A transition-metal-free oxychlorination of alkenyl oximes has be
- Zhang, Xiao-Wei,Xiao, Zu-Feng,Wang, Mei-Mei,Zhuang, Yan-Jun,Kang, Yan-Biao
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supporting information
p. 7275 - 7281
(2016/08/05)
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- Oxime-mediated oxychlorination and oxybromination of unactivated olefins
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An oxime-mediated oxychlorination and oxybromination of unactivated olefins relying on palladium catalysis has been developed. A wide range of chlorinated and brominated isoxazolines has been synthesized in moderate to good yields. To demonstrate the value of the method, the brominated isoxazoline has been further converted to other useful synthetic feedstock.
- Dong, Kui-Yong,Qin, Hai-Tao,Liu, Feng,Zhu, Chen
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supporting information
p. 1419 - 1422
(2015/03/04)
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- Iodine(III)-Mediated Oxy-fluorination of Alkenyl Oximes: An Easy Path to Monofluoromethyl-Substituted Isoxazolines
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A highly regioselective intramolecular oxy-fluorination of alkenyl oximes was achieved. This new transformation represents an efficient method for the preparation of monofluoromethyl-substituted isoxazolines. The synthetic application of the oxy-fluorinat
- Kong, Weidong,Guo, Quanping,Xu, Zhaoqing,Wang, Guoqiang,Jiang, Xianxing,Wang, Rui
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supporting information
p. 3686 - 3689
(2015/08/18)
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- Copper-catalyzed oxyazidation of unactivated alkenes: A facile synthesis of isoxazolines featuring an azido substituent
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A novel and efficient Cu(OAc)2-catalyzed oxyazidation of unactivated alkenes was developed. The reactions are easy to conduct, occur under mild conditions, and form azido-substituted isoxazolines in good yields.
- Zhu, Liping,Yu, Hongmei,Xu, Zhaoqing,Jiang, Xianxing,Lin, Li,Wang, Rui
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supporting information
p. 1562 - 1565
(2014/04/17)
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- Copper-catalyzed 5-endo-trig cyclization of ketoxime carboxylates: A facile synthesis of 2-arylpyrroles
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A novel and facile copper-catalyzed 5-endo-trig cyclization of ketoxime carboxylates for the synthesis of 2-arylpyrroles has been developed. The reaction tolerates a range of functional groups and is a practical procedure for rapid synthesis of 2-arylpyrroles in high yields under mild conditions. the Partner Organisations 2014.
- Du, Wei,Zhao, Mi-Na,Ren, Zhi-Hui,Wang, Yao-Yu,Guan, Zheng-Hui
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supporting information
p. 7437 - 7439
(2014/07/07)
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- Oxime-mediated facile access to 5-methylisoxazoles and applications in the synthesis of valdecoxib and oxacillin
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A palladium-catalyzed efficient synthesis of 5-methylisoxazoles via oxime-mediated functionalization of unactivated olefins is described. The reaction affords a variety of 5-methylisoxazoles in moderate to good yields. To further demonstrate the utility of the method, the rapid synthesis of valdecoxib and oxacillin is reported. (Chemical Equation Presented).
- Dong, Kui-Yong,Qin, Hai-Tao,Bao, Xing-Xing,Liu, Feng,Zhu, Chen
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supporting information
p. 5266 - 5268
(2015/01/09)
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- Synthesis of Z-alkenes from Rh(I)-catalyzed olefin isomerization of β,γ-unsaturated ketones
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Developing olefin isomerization reactions to reach kinetically controlled Z-alkenes is challenging because formation of trans-alkenes is thermodynamically favored under the traditional catalytic conditions using acids, bases, or transition metals as the catalysts. A new synthesis of Z-alkenes from Rh(I)-catalyzed olefin isomerization of β,γ-unsaturated ketones to α,β-unsaturated ketones was developed, providing an easy and efficient way to access various Z-enones.
- Zhuo, Lian-Gang,Yao, Zhong-Ke,Yu, Zhi-Xiang
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supporting information
p. 4634 - 4637
(2013/10/08)
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- DIPHENYLHETEROCYCLE CHOLESTEROL ABSORPTION INHIBITORS
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Various azetidinone, pyrrolidine, imidazolidine, and oxazolidine derivatives are described, as are pharmaceutical compositions containing these compounds and methods of treatment of diseases using these compounds. Other embodiments are also described.
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Page/Page column 273-274
(2008/06/13)
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- Δ2-isoxazolines from β,γ-unsaturated oximes
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3,5-Disubstituted Δ2-isoxazolines can be prepared using the palladium-mediated nucleometalation/ methoxycarbonylation of β,γ-unsaturated oximes. This novel route to this class of compounds is tolerant of a wide variety of functionality in the s
- Mosher, Michael D.,Emmerich, Laura G.,Frost, Katherine S.,Anderson, Benjamin
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p. 535 - 539
(2007/10/03)
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