- Pd-Catalyzed Remote Site-Selective and Stereoselective C(Alkenyl)-H Alkenylation of Unactivated Cycloalkenes
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A palladium-catalyzed alkenylation involving remote δ-position C(alkenyl)-H activation of cycloalkenes reacting with electron-deficient alkenes is described. This method features excellent site selectivity and stereoselectivity to efficiently afford only E-selective highly substituted 1,3-diene derivatives with extra-ligand-free and good functional group tolerance including estrone and free N-H tryptamine under weakly alkaline conditions. Mechanistic studies suggest that picolinamide as a bidentate directing group enables the formation of unique alkenyl palladacycle intermediates.
- Mao, Chun-Li,Zhao, Sheng,Zang, Zhong-Lin,Xiao, Lin,Zhou, Cheng-He,He, Yun,Cai, Gui-Xin
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p. 774 - 787
(2020/01/09)
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- Regioselective intramolecular Markovnikov and anti-Markovnikov hydrofunctionalization of alkenes: Via photoredox catalysis
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Highly regioselective Markovnikov hydrofunctionalization of alkenes was successfully realized via photoredox catalysis by introducing a urea group and fine tuning the hydrogen atom transfer catalysts. The anti-Markovnikov hydroamination of alkenes was also achieved with high yields and stereoselectivities in this work.
- Li, Na,Man, Yunquan,Tang, Bo,Wang, Hongyu,Wang, Kaiye,Xiang, Yanan
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supporting information
p. 11426 - 11429
(2019/09/30)
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- Copper-Catalyzed Divergent Trifluoromethylation/Cyclization of Unactivated Alkenes
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Most of the precedent copper-catalyzed trifluoromethylation reactions of unactivated alkenes concern terminal alkenes, and these processes are terminated in elimination, or nucleophilic addition, or semipinacol rearrangement, or C-H bond functionalization steps. In this study, we develop a trifluoromethylation method for both unactivated terminal and internal alkenes to enable divergent late-stage radical cyclization and achieve high molecular complexity. These cyclizations are well consistent with Baldwin's rule. Furthermore, a kinetic isotope effect (KIE) study and control reactions were conducted, and a plausible mechanism is proposed.
- Zheng, Jing,Deng, Ziyang,Zhang, Yan,Cui, Sunliang
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supporting information
p. 746 - 751
(2016/03/09)
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- "Nanorust"-catalyzed benign oxidation of amines for selective synthesis of nitriles
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Organic nitriles constitute key precursors and central intermediates in organic synthesis. In addition, nitriles represent a versatile motif found in numerous medicinally and biologically important compounds. Generally, these nitriles are synthesized by traditional cyanation procedures using toxic cyanides. Herein, we report the selective and environmentally benign oxidative conversion of primary amines for the synthesis of structurally diverse aromatic, aliphatic and heterocyclic nitriles using a reusable "nanorust" (nanoscale Fe2O3)-based catalysts applying molecular oxygen.
- Jagadeesh, Rajenahally V.,Junge, Henrik,Beller, Matthias
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- Mild and efficient reductive deoxygenation of epoxides to olefins with tin(II) chloride/sodium iodide as a novel reagent
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A highly efficient and green protocol is reported for the reductive deoxygenation of organic epoxides to olefins using tin(II) chloride/sodium iodide as a novel reagent. The reaction gives an excellent yield (85-96%) in ethanol under reflux within 2-10 minutes, without affecting other functional groups. The advantages of our method are the use of inexpensive reagents, the eco-friendly and green reaction conditions, and the short reaction times and high yields.
- Pathe, Gulab Khushalrao,Ahmed, Naseem
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p. 3542 - 3552
(2015/11/17)
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- A comparative LSER study of the reactivity of 2-substituted cyclohex- 1-eneacetic and 2-substituted phenylacetic acids with diazodiphenylmethane in various solvents
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The rate constants for the reaction of 2-substituted cyclohex-1-eneacetic and 2- substituted phenylacetic acids with diazodiphenylmethane were determined in various aprotic solvents at 30°C. To explain the kinetic results through solvent effects, the second-order rate constants of the examined acids were correlated using the Kamlet-Taft solvatochromic equation. The correlations of the kinetic data were carried out by means of multiple linear regression analysis, and the solvent effects on the reaction rates were analyzed in terms of initial and transition state contributions. The opposite signs of the electrophilic and the nucleophilic parameters are in agreement with the well-known mechanism of the reaction of carboxylic acids with diazodiphenylmethane. The quantitative relationship between the molecular structure and the chemical reactivity is discussed, as well as the effect of the molecular geometry on the reactivity of the examined compounds.
- Nikolic,Uscumlic,Juranic, Ivan O.
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experimental part
p. 613 - 622
(2010/02/28)
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- Catalysis of a hydroxyapatite-bound Ru complex: Efficient heterogeneous oxidation of primary amines to nitriles in the presence of molecular oxygen
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A hydroxyapatite-bound Ru complex could efficiently catalyze the aerobic oxidation of various primary amines to nitriles which were further hydrated to amides in the presence of water.
- Mori,Yamaguchi,Mizugaki,Ebitani,Kaneda
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p. 461 - 462
(2007/10/03)
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- Reactivity of 2-Substituted Cyclohex-1-enylacetic Acids with Diazodiphenylmethane in Various Alcohols
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The reactivities of 2-substituted cyclohex-1-enylacetic acids with diazodiphenylmethane in eleven alcohols has been investigated.The solvent effect is interpreted in terms of the influence of the relative permittivity on the rate constants.The multiple linear correlation of log k with the Kirkwood function of relative permittivity.Taft ?* value for the alkyl group of the alcohol and the number of γ-hydrogen atoms in the alcohol nγH was highly successful (R=0.9927).The log k values for the various acids were correlated by using the appropriate form of the extended Hammett equation involving inductive, resonance and steric parameters.The reaction of cyclohex-1-enylacetic acid with diazodiphenylmethane in eleven alcohols shows a good linear free energy relationship with the corresponding reaction of phenylacetic acid (R=0.9793).The results obtained for 2-substituted cyclohex-1-enylacetic acids were compared with the results for ortho-substituted phenylacetic acids under the same experimental conditions.
- Uscumlic, Gordana S.,Muskatirovic, Milan D.
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p. 1799 - 1802
(2007/10/02)
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- Preparation of useful intermediates of dextrorphan - Note I
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Dextrorphan is the main metabolite of Dextromethorphan, a drug with high anti-tussive activity. In this preliminary work we report on the synthesis of two essential intermediates for its preparation: 2-(1-cyclohexenyl)ethyl amine and (R;S)-1-(4-methoxy-benzyl)-2-methyl-1,2,3,4,5,6,7,8-octahydroisoquinol ine.
- Passarotti,Valenti,Grianti
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p. 472 - 474
(2007/10/02)
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- Nickel-catalyzed dehydrogenation of amines to nitriles
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Aliphatic primary amines having α-methylene underwent oxidative dehydrogenation on treatment with NiSO4 as a catalyst and K2S2O8 as an oxidant to give the corresponding nitriles in good yields. Benzhydrylamine was converted to benzhydrylideneamine quantitatively under the same reaction conditions.
- Yamazaki,Yamazaki
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p. 301 - 303
(2007/10/02)
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- Photochemistry of Succinimides with a Cycloalkenylalkyl Group in the Side Chain. Competitive Norrish Type II and Paterno-Buchi Reactions
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Photolysis of N-succinimides (9c-f) (m>/=2) afforded mainly azepinediones (13c-f) with ring enlargement as the Norrish type II cyclization products.In the case of m=1, spiro-azepinedione derivatives (11a, b) were obtained in addition to tricyclic nitrogen heterocycles (10a, b), the Norrish type II products.These spiro-azepinediones are probably formed via imide imide-oxetanes by the intramolecular Paterno-Buchi reaction of these succinimides in competition with the type II processes.Keywords: N-succinimide; Norrish type II reaction; oxetane formation; azepinedione; spiro compound; photochemistry.
- Machida, Minoru,Oda, Kazuaki,Kanaoka, Yuichi
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p. 950 - 956
(2007/10/02)
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- Diazaestrones and analogs. I. Pharmacological study and synthesis of heterosteroid analogs to establish structure-analgesic activity relationships
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With the intention of showing the effect, about pharmacological properties, in replacing two estron asymetric carbon by nitrogen atoms and removal of angular methyl from steroid, stereospecific synthesis of 8,13-diazaestron and several substituted similar compounds was realized from β-1-(succinimidoethyl)-dihydroisoquinolines, precursors of a C open ring synthesis. The splitting of the 2-methoxydiazaestron methyl ester was carried out by mean of binaphthylphosphoric acid, and synthesis of several modified analogs of heterosteroid, was carried out to determine the effect of aromatic ring reduction, lactamic carbonyl reduction, and distance between 8 and 13 nitrogen atoms, about pharmacological activity. Hormonal, spasmolytic and analgesic activities were studied, good results were observed in analgesic activity.
- Hocquaux,Marcot,Redeuilh,et al.
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p. 319 - 329
(2007/10/02)
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- LONG-ACTING CONTRACEPTIVE AGENTS: LEVONORGESTREL ESTERS OF UNSATURATED ACIDS
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Esters of levonorgestrel (13β-ethyl-17α-ethynyl-17β-hydroxygon-4-en-3-one) with a variety of unsaturated carboxylic acids have been synthesized for evaluation as potential long-acting, injectable contraceptive agents.
- Wan, A. S. C.,Ngiam, T. L.,Leung, S. L.,Go, M. L.,Francisco, C. G.,et al.
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p. 339 - 348
(2007/10/02)
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