- Selective synthesis of iminodioxaspirononanes and diazaspirononanes using formic acid-activated Mn(III) oxidation of N1,N3-disubstitued malonamides with 1,1-diarylethenes
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The Mn(III)-based oxidation of N1,N3-disubstituted malonamides with alkenes by Kurosawa spirolactonization using malonic acid afforded iminodihydrofurans. A similar reaction with Mn(OAc)3, which was activated by HCO2
- El-Deeb, Ibrahim Yussif,Nakano, Y?ki,Nishino, Hiroshi,Shimoishi, Ryutaro,Wada, Ryosei
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- Base-promoted addition of DMA with 1,1-diarylethylenes: Application to a total synthesis of (-)-sacidumlignan B
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A base-promoted addition of DMA (N,N-dimethylacetamide) to 1,1-diarylethylenes has been developed, and it provides a new strategy for the synthesis of N,N-dimethyl-4,4-diarylbutanamides from 1,1-diarylethylenes at room temperature. This method allows us to achieve the goal of synthesizing (-)-sacidumlignan B, and provides simple operation and broad substrate scope by avoiding the use of transition metal catalysts.
- Luo, Zhen-Biao,Peng, Yu,Wang, Ya-Wen
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supporting information
p. 2054 - 2057
(2020/03/27)
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- Electrophilic borylation of terminal alkenes with BBr3/2,6-disubstituted pyridines
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A variety of terminal alkenes, as well as heteroaromatic compounds, are borylated by the combined use of BBr3/2,6-dichloropyridine (B3) or BBr3/2,6-lutidine (B5). α,α-Diarylalkenes prefer the former reagent combination, while other alkenes prefer the latter. Mechanistic considerations strongly suggest that the former and latter reactions proceed through electrophilic substitution reactions with BBr3 and [BBr2·B5]+BBr4-, respectively.
- Tanaka, Shinya,Saito, Yuki,Yamamoto, Takaya,Hattori, Tetsutaro
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supporting information
p. 1828 - 1831
(2018/04/14)
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- Facile synthesis of indolelactones using Mn(III)-based oxidative substitution-cyclization reaction
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Based on the oxidation of indole with Mn(OAc)3 in the presence of 1,1-diarylethenes affording 3-vinyl-substituted indoles, a similar oxidation using indole-2-carboxylic acids was evaluated in order to effectively introduce the substituent group to the C-3 position of the indolecarboxylic acids. The coupling reaction followed by oxidative cyclization smoothly proceeded at room temperature in an AcOH-HCO2H mixed solvent to give the desired indolelactones in high yields. The reaction details, the structure determination of the products and a brief reaction mechanism are described.
- Inoue, Takeshi,Nishino, Hiroshi
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p. 431 - 450
(2019/07/31)
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- Synthesis of 2,2-diarylvinyl phenyl selenides by dehydration of 2-hydroxyalkyl phenyl selenides
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A novel route to 2,2-diarylvinyl phenyl selenides is reported by dehydration of the corresponding 2,2-diaryl-2-hydroxyethyl phenyl selenides, prepared by oxyphenylselenenylations of the corresponding 1,1-diarylethylenes, upon treatment with p-toluenesulfonic acid.
- Stuhr-Hansen, Nicolai
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- Scandium(III) Trifluoromethanesulfonate Catalyzed Selective Reactions of Donor–Acceptor Cyclopropanes with 1,1-Diphenylethanols: An Approach to Polysubstituted Olefins
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An unexpected synthetic approach to polysubstituted olefins through the scandium(III) trifluoromethanesulfonate catalyzed ring-opening reaction of donor–acceptor cyclopropanes with 1,1-diphenylethanols was developed. The reactions, which are experimentally easy to handle, feature tolerance of various functional groups and mild reaction conditions. On the basis of experimental evidence, a plausible mechanism was also proposed.
- Zhu, Xiaoyan,Hong, Gang,Hu, Chen,Wu, Shengying,Wang, Limin
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supporting information
p. 1547 - 1551
(2017/04/01)
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- Advanced Synthesis of Dihydrofurans: Effect of Formic Acid on the Mn(III)-Based Oxidation
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The Mn(III)-based oxidation of a tertiary alkylamine, such as nitrilotris(ethane-2,1-diyl) tris(3-oxobutanoate) (1) with 1,1-diphenylethene (2a), effectively proceeded in an acetic acid-formic acid mixed solvent to give nitrilotris(ethane-2,1-diyl) tris(2-methyl-5,5-diphenyl-4,5-dihydrofuran-3-carboxylate) (3). Other typical Mn(III)-based reactions of various β-diketo esters 4a-e, 2,4-pentanedione (6a), malonic acid (6b), and diethyl malonate (6c) with 1,1-diarylthenes 2a-d were also investigated in a similar acetic acid-formic acid mixed solvent and the reaction rate was accelerated and the product yield increased.
- Matsumoto, Risa,Nishino, Hiroshi
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supporting information
p. 1807 - 1816
(2015/08/06)
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- A simple and efficient copper oxide-catalyzed Barbier-Grignard reaction of unactivated aryl or alkyl bromides with ester
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An efficient one-pot route to synthesize tertiary alcohol compounds using Barbier-Grignard reaction of unactivated alkyl or aryl bromides with ester in THF at 65 C catalyzed by CuO has been developed and systematically investigated. A wide range of substituted tertiary alcohol compounds were obtained in good to high yields. The reaction is highly chemoselective. The mechanism involving the leaving group of R2O-group is discussed.
- Gao, Fei,Deng, Xiang-Jun,Tang, Yu,Tang, Jin-Peng,Yang, Jun,Zhang, Yuan-Ming
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supporting information
p. 880 - 883
(2014/02/14)
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- A simple and efficient copper oxide-catalyzed Barbier-Grignard reaction of unactivated aryl or alkyl bromides with ester
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An efficient one-pot route to synthesize tertiary alcohol compounds using Barbier-Grignard reaction of unactivated alkyl or aryl bromides with ester in THF at 65 °C catalyzed by CuO has been developed and systematically investigated. A wide range of substituted tertiary alcohol compounds were obtained in good to high yields. The reaction is highly chemoselective. The mechanism involving the leaving group of R2O-group is discussed.
- Gao, Fei,Deng, Xiang-Jun,Tang, Yu,Tang, Jin-Peng,Yang, Jun,Zhang, Yuan-Ming
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supporting information
p. 880 - 883
(2015/03/03)
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- The effect of ring substitution on the O-neophyl rearrangement of 1,1-diarylalkoxyl radicals. A product and time-resolved kinetic study
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A product and time-resolved kinetic study of the effect of ring substitution on the reactivity of 1,1-diarylalkoxyl radicals has been carried out. The radicals undergo an O-neophyl shift to give the isomeric 1-aryl-1-aryloxyalkyl radicals from which the corresponding aromatic ketones are formed. The rearrangement rate constants are influenced by ring substitution, increasing in the presence of electron-withdrawing substituents and decreasing in the presence of electron-donating ones. From the results of product and kinetic studies, the following migratory aptitudes have been obtained: 4-trifluoromethylphenyl > phenyl ? 4-methylphenyl > 4-methoxyphenyl. Excellent Hammett-type correlations between the σ+ substituent constants and both the visible absorption band maxima and the rearrangement rate constants have been obtained. The experimental results indicate that the rearrangement is governed by electronic effects in the starting 1,1-diarylalkoxyl radicals, whereas the stability of the rearranged carbon-centered radical plays a minor role, in line with a reactant-like transition state, strongly supporting the hypothesis that the O-neophyl rearrangement of 1,1-diarylalkoxyl radicals proceeds through a concerted mechanism.
- Aureliano Antunes, Carla S.,Bietti, Massimo,Ercolani, Gianfranco,Lanzalunga, Osvaldo,Salamone, Michela
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p. 3884 - 3891
(2007/10/03)
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- Non-linearity and non-additivity of substituent effects in solvolysis of 1,1-diphenylethyl p-nitrobenzoates
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The solvolysis rates of 1,1-diarylethyl p-nitrobenzoates and chlorides Y-Ar(X-Ar)CMe-LG (LG = OPNB, Cl) have been determined conductimetrically at 25°C in 80% (v/v) aqueous acetone. A linear Yukawa-Tsuno (Y-T) correlation was found for the symmetrical subseries (X = Y), showing a precise additivity relationship for the whole substituent range with ρsym = -3.78 and rsym = 0.77. The unsymmetrical subsets (X ≠ Y) gave statistically less reliable Y-T correlations, the apparent p value decreasing significantly when the fixed substituent Y becomes more electron-donating, which is in line with expectations from the Reactivity-Selectivity Relationship. In the whole dispersion pattern, both strong p-π-donor and electron-withdrawing substituents in any fixed-Y subsets exhibit significant rate-enhancement deviations from the points of X = Y on the reference ρsym line, which suggests an anti-Hammond shift of the transition state. However, there was a precise Extended Bronsted Linear Relationship between the pKR+ values for the hydration of 1,1-diarylethylenes and the rates of solvolysis of the p-nitrobenzoates with a slope of unity (α = 1.03). This is direct, convincing evidence that there is no significant shift of the transition-state coordinate over the whole range of substituent change.
- Uddin, Md. Khabir,Fujio, Mizue,Kim, Hyun-Joong,Rappoport, Zvi,Tsuno, Yuho
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p. 1371 - 1379
(2007/10/03)
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- Activation conditions play a key role in the activity of zeolite CaY: NMR and product studies of Bronsted acidity
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CaY, activated under different conditions, was characterized with 1H, 31P, and 1H/27A] double resonance MAS NMR. The 1H MAS NMR spectra of CaY, calcined in an oven at 500 °C, shows resonances from H2O (bound to Ca2+ and the zeolite framework), CaOH+, aluminum hydroxides, silanols, and Bronsted acid sites. No evidence for Lewis acidity is observed on adsorption of trimethylphosphine, and an estimate of ≈16 Bronsted acid sites per unit cell is obtained for this sample. CaY activated in an oven at higher temperatures contains less water, but all the other species are still present. In contrast, CaY activated by slow ramping of the temperature under vacuum to 500 or 600 °C shows a much lower concentration of Bronsted acid sites (1/unit cell). Again, no evidence for Lewis acidity was observed. These NMR results have been utilized to understand the very different product distributions that are observed for reactions of 1,1- and 1,2-diarylethylenes in zeolite CaY activated in an oven (in air) and under vacuum. Samples with high concentrations of Bronsted acid sites react stoichiometrically with these sites, yielding diarylalkanes. At low concentrations, the Bronsted acid sites can act catalytically resulting in isomerization reactions.
- Kao, Hsien-Ming,Grey, Clare P.,Pitchumani, Kasi,Lakshminarasimhan,Ramamurthy
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p. 5627 - 5638
(2007/10/03)
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