- Bio-inspired asymmetric aldehyde arylations catalyzed by rhodium-cyclodextrin self-inclusion complexes
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Transition-metal catalysts are powerful tools for carbon-carbon bond-forming reactions that are difficult to achieve using native enzymes. Enzymes that exhibit inherent selectivities and reactivities through host-guest interactions have inspired widesprea
- Asahi, Kaoru,Fujiwara, Shin-Ichi,Iwasaki, Takanori,Kambe, Nobuaki,Takahashi, Ryota,Tsuda, Susumu,Ueda, Ryoji,Yamauchi, Hiroki
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supporting information
p. 801 - 807
(2022/02/03)
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- Generation of Aryllithium Reagents from N -Arylpyrroles Using Lithium
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Treatment of 1-aryl-2,5-diphenylpyrroles with lithium powder in tetrahydrofuran at 0 °C results in the generation of the corresponding aryllithium reagents through reductive C-N bond cleavage.
- Ozaki, Tomoya,Kaga, Atsushi,Saito, Hayate,Yorimitsu, Hideki
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p. 3019 - 3028
(2021/06/02)
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- Direct allylation of benzyl alcohols, diarylmethanols, and triarylmethanols mediated by XtalFluor-E
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We report the direct allylation of benzyl alcohols, diarylmethanols and triarylmethanols mediated by XtalFluor-E using allyltrimethylsilane. The resulting allylated products are obtained in moderate to high yield.
- Lebleu, Thomas,Paquin, Jean-Fran?ois
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supporting information
p. 442 - 444
(2017/01/10)
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- Exploring the Reactivity of α-Lithiated Aryl Benzyl Ethers: Inhibition of the [1,2]-Wittig Rearrangement and the Mechanistic Proposal Revisited
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By carefully controlling the reaction temperature, treatment of aryl benzyl ethers with tBuLi selectively leads to α-lithiation, generating stable organolithiums that can be directly trapped with a variety of selected electrophiles, before they can undergo the expected [1,2]-Wittig rearrangement. This rearrangement has been deeply studied, both experimentally and computationally, with aryl α-lithiated benzyl ethers bearing different substituents at the aryl ring. The obtained results support the competence of a concerted anionic intramolecular addition/elimination sequence and a radical dissociation/recombination sequence for explaining the tendency of migration for aryl groups. The more favored rearrangements are found for substrates with electron-poor aryl groups that favor the anionic pathway.
- Velasco, Rocío,Silva López, Carlos,Nieto Faza, Olalla,Sanz, Roberto
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p. 15058 - 15068
(2016/10/11)
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- Design, synthesis and biological evaluation of B-region modified diarylalkyl amide analogues as novel TRPV1 antagonists
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Design, synthesis and biological evaluation of B-region, known to be a dipolar interacting pharmacophore, modified diarylalkyl amide analogues for novel TRPV1 (transient receptor potential channel, vanilloid subfamily member 1) antagonists was described. A variety of moieties including guanidines, heterocyclic rings, cinnamides, and α-substituted acetamides were introduced at the B-region. TRPV1 antagonistic activities of these analogues were evaluated by 45Ca2+ uptake assay in rat DRG neuron. In particular, α,α-difluoroamide 53 exhibited 3-fold more potent TRPV1 antagonistic activity (IC50 = 0.058 μM) than the parent amide analogue 6.
- Han, Young Taek,Yang, Shao-Mei,Wang, Xiao-Yuan,Li, Fu-Nan
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p. 440 - 451
(2014/04/17)
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- Palladium-catalyzed arylation of aldehydes with bromo-substituted 1,3-diaryl-imidazoline carbene ligand
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The combination of 0 valent palladium precursor and bromo-substituted 1,3-diaryl-imidazoline carbene ligand precursor such as 1-(2-bromophenyl)-3-(2,6-diisopropylphenyl)-imidazolinium chloride 1a exhibited high catalytic activity for the 1,2-addition of arylboronic acids to aldehydes including aqueous formaldehyde.
- Yamamoto, Tetsuya,Furusawa, Takuma,Zhumagazin, Azamat,Yamakawa, Tetsu,Oe, Yohei,Ohta, Tetsuo
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- Synthesis of fluorenone derivatives through Pd-catalyzed dehydrogenative cyclization
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Palladium-catalyzed dual C-H functionalization of benzophenones to form fluorenones by oxidative dehydrogenative cyclization is reported. This method provides a concise and effective route toward the synthesis of fluorenone derivatives, which shows outstanding functional group compatibility.
- Li, Hu,Zhu, Ru-Yi,Shi, Wen-Juan,He, Ke-Han,Shi, Zhang-Jie
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supporting information
p. 4850 - 4853,4
(2012/12/12)
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- N-heterocyclic carbene-amide rhodium(I) complexes: Structures, dynamics, and catalysis
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The amide-functionalized imidazolium salts [BocNHCH2CH 2ImR]X (R = Me, X = I, 1a; R = benzyl, X = Br, 1b; R = trityl, X = Cl, 1c) bearing increasingly bulky N-alkyl substituents were prepared in high yields by direct alkylation of the (2-imidazol-1-yl-ethyl)carbamic acid tert-butyl ester; 1c is a crystalline solid also characterized by X-ray diffraction. These salts are precursors for the synthesis of rhodium(I) complexes [Rh(NBD)X(NHC)] (NHC = 1-(2-NHBoc-ethyl)-3-R-imidazolin-2-ylidene; X = Cl, R = Me (3a), R = benzyl (3b), R = trityl (3c); X = I, R = Me (4a)). All the complexes display restricted rotation about the metal-carbene bond; however, while the rotation barriers calculated for 3a,b and 4a matched the experimental values, unexpectedly this was not true in the case of 3c, where the experimental value was equal to that obtained for compound 3b (58.6 kJ mol-1) and much smaller with respect to the calculated one (100.0 kJ mol-1). The catalytic activity of the neutral rhodium(I) complexes 3a-c in the hydrosilylation of terminal alkynes with HSiMe2Ph has been investigated with PhC≡CH, TolC≡CH, nBuC≡CH, Et 3SiC≡CH, and (CPh2OH)C≡CH as substrates. The steric hindrance on the N-heterocyclic ligand and on the alkyne substrates affects conversion and selectivity: for the former the best results were achieved employing the less encumbered 3a catalyst with TolC≡CH, whereas by employing hindered alkynes such as Et3SiC≡CH or (CPh 2OH)C≡CH the hydrosilylation leads only to the formation of the β-(E)-vinylsilane and α-bis(silyl)alkene isomers. The complexes 3a,b have also been employed in the addition of arylaldehydes with phenylboronic acid, and like in the hydrosylylation case, the best results were obtained using 3a in the presence of aldehydes bearing electron-withdrawing groups, such as 4-cyanobenzaldehyde and 4-acetylbenzaldehyde as substrates.
- Busetto, Luigi,Cassani, M. Cristina,Femoni, Cristina,Mancinelli, Michele,Mazzanti, Andrea,Mazzoni, Rita,Solinas, Gavino
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experimental part
p. 5258 - 5272
(2011/12/02)
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- In situ preparation of rhodium/N-heterocyclic carbene complexes and use for addition of arylboronic acids to aldehydes
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(Chemical Equation Presented) The in situ prepared three component system [RhCl(COD)]2/imidazolidinium salts (2, 4) and KOBut catalyses the addition of phenylboronic acid to sterically hindered aldehydes affording the corresponding arylated secondary alcohols in good yields. Four novel 1,3-dialkylimidazolidinium (2-4) salts as NHC precursors were synthesized from N,N′-dialkylethylenediamine.
- Kilincarslan, Rafet,Yigit, Murat,Oezdemir, Ismail,Cetinkaya, Engin,Cetinkaya, Bekir
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- Novel azolinium/rhodium system catalyzed addition of arylboronic acids to aldehydes
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There novel 1,3-dialkylperhydrobenzimidazolinium (2a-c) and two 1,3-dialkylimidazolinium salts (4a,b) as NHC precursors were synthesized from N,N′-dialkyl-1,2-cyclohexanediamine dihydrochloride and 1,2-dialkylpropanediamine dihydrochloride. The in situ prepared three component system [RhCl(COD)]2 / imidazolinium salts (2, 4) and KOBut catalyses the addition of phenylboronic acid to sterically hindered aldehydes affording the corresponding arylated secondary alcohols in good yields.
- Oezdemir, Ismail,Yigit, Murat,Cetinkaya, Engin,Cetinkaya, Bekir
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p. 1371 - 1379
(2007/10/03)
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- Novel rhodium-1,3-dialkyl-3,4,5,6-tetrahydropyrimidin-2-ylidene complexes as catalysts for arylation of aromatic aldehydes
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Six new rhodium-tetrahydropyrimidin-2-ylidene complexes (2a-f) have been prepared and characterized by C, H, N analysis, 1H NMR and 13C NMR. Phenylboronic acid reacts with aldehydes in the presence of a catalytic amount of the new rhodium(I)-carbene complexes, RhCl(COD)(1,3- dialkyl-3,4,5,6-tetrahydropyrimidin-2-ylidene), (2a-f), to give the corresponding secondary aryl alcohols in good yields (72-96%).
- ?zdemir, Ismail,Demir, Serpil,?etinkaya, Bekir,?etinkaya, Engin
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p. 5849 - 5855
(2007/10/03)
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- 17BETA-HYDROXYSTEROID DEHYDROGENASE TYPE 3 INHIBITORS FOR THE TREATMENT OF ANDROGEN DEPENDENT DISEASES
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In its many embodiments, the present invention provides a novel class of compounds as inhibitors of type 3 17?-hydroxysteroid dehydrogenase, methods of preparing such compounds, pharmaceutical compositions containing one or more such compounds, methods of
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- Structural changes in concentrated solutions of alkali metal monosubstituted benzophenone radical anions as deduced front1H NMR measurements
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The radical anions of monosubstituted benzophenones (including 2-, 3- and 4-methyl-, 4-tert-butyl- and 4-phenylbenzophenone) with lithium, sodium and potassium as countercations in tetrahydrofuran (THF) were studied by paramagnetic solvent 1H NMR shift measurements in the concentration range ca 0.1-1.0 M. In addition to the cation effects, marked positional isomer and substituent effects were found for (1) molar paramagnetism, (2) magnetic state, (3) solubility, (4) structural stability with respect to concentration or addition of cosolvents and (5) rapidity of attainment of their equilibrium structure. The major conclusions which can be drawn are (a) the solvation behavior of the countercation is governed by the anion, (b) an alkyl group in the 4-position makes the structure of the lithium and sodium monosubstituted benzophenone radical anions concentration dependent and (c) in most cases, alkali metal aromatic ketone radical anions generated by electron transfer from the corresponding naphthalene radical anion attain their equilibrium structure rapidly. The data are interpreted on the basis of the involvement of spin-triplet interactions within 'dimers' or higher clusters. Copyright
- Micha-Screttas, Maria,Heropoulos, Georgios A.,Steele, Barry R.
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p. 586 - 592
(2007/10/03)
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