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Artículos de revistas sobre el tema "Absolute asymmetric catalysis"

Autor: Grafiati

Publicado: 25 de mayo de 2024

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1

Kaupp, Gerd y Michael Haak. "Absolute Asymmetric Synthesis by Irradiation of Chiral Crystals". Angewandte Chemie International Edition in English 32, n.º 5 (mayo de 1993): 694–95. http://dx.doi.org/10.1002/anie.199306941.

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2

Lin, Yun-Ming, Zhongtao Li y Julie Boucau. "Predicting the R/S absolute configuration in asymmetric bifunctional catalysis (ABC)". Tetrahedron Letters 48, n.º 30 (julio de 2007): 5275–78. http://dx.doi.org/10.1016/j.tetlet.2007.05.131.

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3

Buchcic-Szychowska, Aleksandra, Anna Zawisza, Stanisław Leśniak y Michał Rachwalski. "Highly Efficient Asymmetric Morita–Baylis–Hillman Reaction Promoted by Chiral Aziridine-Phosphines". Catalysts 12, n.º 4 (31 de marzo de 2022): 394. http://dx.doi.org/10.3390/catal12040394.

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Continuing our research on the use of organophosphorus derivatives of aziridines in asymmetric synthesis and expanding the scope of their applicability, chiral aziridine-phosphines obtained earlier in our laboratory were used as chiral catalysts in the asymmetric Morita–Baylis–Hillman reaction of methyl vinyl ketone and methyl acrylate with various aromatic aldehydes. The desired chiral products were formed in moderate to high chemical yields and with enantiomeric excess reaching value of 98% ee in some cases. The use of catalysts being pairs of enantiomers led to the desired products with opposite absolute configurations.

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4

Feringa, Ben L. y Richard A. van Delden. "Absolute Asymmetric Synthesis: The Origin, Control, and Amplification of Chirality". Angewandte Chemie International Edition 38, n.º 23 (7 de diciembre de 1999): 3418–38. http://dx.doi.org/10.1002/(sici)1521-3773(19991203)38:23<3418::aid-anie3418>3.0.co;2-v.

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5

Barron, L. D. "True and false chirality and absolute asymmetric synthesis". Journal of the American Chemical Society 108, n.º 18 (septiembre de 1986): 5539–42. http://dx.doi.org/10.1021/ja00278a029.

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6

Yamamoto, Satoshi, Kenji Matsuda y Masahiro Irie. "Absolute Asymmetric Photocyclization of a Photochromic Diarylethene Derivative in Single Crystals". Angewandte Chemie International Edition 42, n.º 14 (11 de abril de 2003): 1636–39. http://dx.doi.org/10.1002/anie.200250417.

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7

Kuhn, Alexander y Peer Fischer. "Absolute Asymmetric Reduction Based on the Relative Orientation of Achiral Reactants". Angewandte Chemie International Edition 48, n.º 37 (1 de septiembre de 2009): 6857–60. http://dx.doi.org/10.1002/anie.200902841.

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8

Wu, Yusheng, Lothar Esser y Jef K. De Brabander. "Revision of the Absolute Configuration of Salicylihalamide A through Asymmetric Total Synthesis". Angewandte Chemie 39, n.º 23 (1 de diciembre de 2000): 4308–10. http://dx.doi.org/10.1002/1521-3773(20001201)39:23<4308::aid-anie4308>3.0.co;2-4.

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9

Bielski, Roman y Michal Tencer. "Macroscopically chiral system of three independent orientational effects as a condition for absolute asymmetric synthesis". Canadian Journal of Chemistry 81, n.º 9 (1 de septiembre de 2003): 1029–37. http://dx.doi.org/10.1139/v03-128.

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The paper introduces the concept of using three independent, macroscopic factors affecting mutual orientation of the reactant molecules to accomplish absolute asymmetric synthesis. Unlike with other methodologies of asymmetric synthesis in physical fields, none of the utilized factors is chiral in itself (as, e.g., circularly polarized light would be), but the combination of the three constitutes a macroscopically chiral influence. Examples of applicable directional factors are time-even vector fields (e.g., electric field and the directional effects of surfaces and interfaces) and the time-odd directional transport with encounter control. The directional factors employed may act simultaneously or, if their effect can be preserved, consecutively, thus allowing, e.g., a repeat use of the electric field. The electric field strength needed to achieve a practically useful degree of molecular orientation was estimated to be ca. 3 MV/cm, which is now commonly achieved with organic materials in the area of nonlinear optics. Practical implications are discussed, as well as the implications for the origins of natural homochirality.Key words: macroscopic chirality, absolute asymmetric synthesis, homochirality, physical fields.

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10

Kaimori, Yoshiyasu, Yui Hiyoshi, Tsuneomi Kawasaki, Arimasa Matsumoto y Kenso Soai. "Formation of enantioenriched alkanol with stochastic distribution of enantiomers in the absolute asymmetric synthesis under heterogeneous solid–vapor phase conditions". Chemical Communications 55, n.º 36 (2019): 5223–26. http://dx.doi.org/10.1039/c9cc01875a.

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11

Kaupp, Gerd y Thorsten Marquardt. "Absolute Asymmetric Synthesis Solely under the Influence of a Static Homogeneous Magnetic Field?" Angewandte Chemie International Edition in English 33, n.º 14 (2 de agosto de 1994): 1459–61. http://dx.doi.org/10.1002/anie.199414591.

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12

Solladié-Cavallo, A., M. Roje, M. Giraud-Roux, Y. Chen, N. Berova y V. Sunjic. "Trans-diaryl epoxides: Asymmetric synthesis, ring-opening, and absolute configuration". Chirality 16, n.º 3 (2004): 196–203. http://dx.doi.org/10.1002/chir.20005.

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13

Maligres, Peter E., Zhiguo Jake Song, Neil A. Strotman, Jinquin Yin, Tao Pei, Hallena R. Strotman, Tetsuji Itoh, Edward C. Sherer y Guy R. Humphrey. "Synthesis of Fused Oxepane HIV Integrase Inhibitor MK-1376". Synthesis 52, n.º 22 (16 de marzo de 2020): 3378–88. http://dx.doi.org/10.1055/s-0040-1707994.

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Controlling the absolute and relative stereochemistry of a seven-membered oxepane in the formation of HIV integrase inhibitor MK-1376 was accomplished through a strategy involving the use of asymmetric allylation and stereoconvergent, substrate-directed installation of an amine fragment. Surprising reactivity was demonstrated during the asymmetric allylation in which the allyl-pyrimidone product was formed reversibly. The stereoconvergent amine addition was accomplished through an elimination/addition sequence involving a quinone methide reactive intermediate, and nucleophilic trapping of the reactive quinone methide intermediate with methylamine. This novel approach delivered MK-1376, offering 100-fold greater productivity and 50-fold less waste than the initial synthetic chemistry route.

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14

Patzer, Michael, Nils Nöthling, Richard Goddard y Christian W. Lehmann. "Absolute Configuration of In Situ Crystallized (+)-γ-Decalactone". Chemistry 3, n.º 2 (21 de abril de 2021): 578–84. http://dx.doi.org/10.3390/chemistry3020040.

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Knowledge about the absolute configuration of small bioactive organic molecules is essential in pharmaceutical research because enantiomers can exhibit considerably different effects on living organisms. X-ray crystallography enables chemists to determine the absolute configuration of an enantiopure compound due to anomalous dispersion. Here, we present the determination of the absolute configuration of the flavoring agent (+)-γ-decalactone, which is liquid under ambient conditions. Single crystals were grown from the liquid in a glass capillary by in situ cryo-crystallization. Diffraction data collection was performed using Cu-Kα radiation. The absolute configuration was confirmed. The molecule consists of a linear aliphatic non-polar backbone and a polar lactone head. In the solid state, layers of polar and non-polar sections of the molecule alternating along the c-axis of the unit cell are observed. In favorable cases, this method of absolute configuration determination of pure liquid (bioactive) agents or liquid products from asymmetric catalysis is a convenient alternative to conventional methods of absolute structure determination, such as optical rotatory dispersion, vibrational circular dichroism, ultraviolet-visible spectroscopy, use of chiral shift reagents in proton NMR and Coulomb explosion imaging.

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15

Rajegowda, H. R., P. Raghavendra Kumar, Amar Hosamani y R. J. Butcher. "Synthesis, characterization and determination of absolute structures of palladium complexes of novel chiral acyclic tellurated Schiff base ligands". New Journal of Chemistry 42, n.º 8 (2018): 6264–73. http://dx.doi.org/10.1039/c8nj00727f.

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16

Castagnetto, Jesus M., Xiaodong Xu, Nina D. Berova y James W. Canary. "Absolute configurational assignment of self-organizing asymmetric tripodal ligand-metal complexes". Chirality 9, n.º 5-6 (1997): 616–22. http://dx.doi.org/10.1002/(sici)1520-636x(1997)9:5/6<616::aid-chir32>3.0.co;2-p.

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17

Monaco, Guglielmo, Maximilian Tiffner, Antonia Di Mola, Wouter Herrebout, Mario Waser y Antonio Massa. "Chiral Phase Transfer Catalysis in the Asymmetric Synthesis of a 3,3-Disubstituted Isoindolinone and Determination of Its Absolute Configuration by VCD Spectroscopy". Molecules 25, n.º 10 (12 de mayo de 2020): 2272. http://dx.doi.org/10.3390/molecules25102272.

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In this work we report our endeavors toward the development of an asymmetric synthesis of a 3,3-disubstituted isoindolinone, dimethyl 2-(1-methyl-3-oxoisoindolin-1-yl)malonate, via asymmetric cascade reaction of 2-acetylbenzonitrile with dimethylmalonate and the determination of its absolute configuration (AC) by vibrational circular dichroism (VCD). Bifunctional ammonium salts, derived from trans-1,2-cyclohexanediamine in combination with inorganic bases under phase transfer conditions, were the most effective catalytic systems, leading to the target in high yields and moderate enantioselectivity. An efficient process of heterochiral crystallization allowed the increase of the enantiopurity up to 96% ee and in an acceptable overall yield. An important aim of the present work is the comparison of different VCD methodologies for AC determination of the target compound.

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18

Charlton, James L., Guy L. Plourde, K. Koh y Anthony S. Secco. "Asymmetric synthesis of podophyllotoxin analogs". Canadian Journal of Chemistry 68, n.º 11 (1 de noviembre de 1990): 2022–27. http://dx.doi.org/10.1139/v90-309.

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Two analogs of podophyllotoxin, with the same absolute stereochemistry as the natural product, have been synthesized from the cycloadduct between α-hydroxy-α′-phenyl-o-quinodimefhane and the fumarate of S-methyl lactate. After initial attempts to produce the cycloadduct from photochemically generated α-hydroxy-α′-phenyl-o-quinodimethane failed, a study of the thermal generation and reaction of α-hydroxy-o-quinodimethane with the fumarate and acrylate of S-methyl lactate was made. A comparison was made of the diastereoselectivity of these cycloaddition reactions to those previously reported, in which the o-quinodimethane was generated photochemically. The α-hydroxy-o-quinodimethane was produced both by the known thermolysis of benzocyclobutenol and by thermolysis of 1-hydroxy-1,3-dihydrobenzo[c]thiophene-2,2-dioxide. The diastereomeric excess for the cycloaddition reactions was found to be greater than 95% with modest (ca. 55%) isolated yields of the major cycloadducts. Following these model studies, it was found that α-hydroxy-α′-phenyl-o-quinodimethane produced thermally from 1-hydroxy-3-phenyl-1,3-dihydrobenzo[c]thiophene-2,2-dioxide could be added to the fumarate of S-methyl lactate with high diastereoselectivity and good yield. The product of this reaction was converted to the podophyllotoxin analogs 7 and 17. Keywords: o-quinodimethanes, asymmetric, Diels–Alder, lactate, podophyllotoxin, lignan.

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19

Gorobets, Evgueni, Masood Parvez, Bronwen MM Wheatley y Brian A. Keay. "Use of 1H NMR chemical shifts to determine the absolute configuration and enantiomeric purity for enantiomers of 3,3′-disubstituted-MeO-BIPHEP derivatives". Canadian Journal of Chemistry 84, n.º 2 (1 de febrero de 2006): 93–98. http://dx.doi.org/10.1139/v05-230.

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The absolute configuration of a series of 3,3′-disubstituted-MeO-BIPHEP derivatives can be determined by the 1H NMR chemical shift of the methoxyl group when the 3,3′-disubsituted-MeO-BIPHEP derivative is mixed with ()-(2R,3R)-dibenzoyltartaric acid (()-DBTA) (1:2) and its NMR spectrum is run in CDCl3. The chemical shift of the methoxyl group in the Sax enantiomer always occurred at higher field than the corresponding Rax enantiomer. Integration of the corresponding methoxyl signals provides the enantiomeric purity of any mixtures.Key words: assignment of absolute configuration, 2,2′-bis(diphenylphosphino)-1,1′-biaryls, MeO-BIPHEP derivatives, asymmetric Heck reaction, 1H NMR chemical shifts.

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20

Tan, Dong‐Xing, Jie Zhou, Chao‐You Liu y Fu‐She Han. "Enantioselective Total Synthesis and Absolute Configuration Assignment of (+)‐Tronocarpine Enabled by an Asymmetric Michael/Aldol Reaction". Angewandte Chemie International Edition 59, n.º 10 (3 de febrero de 2020): 3834–39. http://dx.doi.org/10.1002/anie.201914868.

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21

Morimoto, Masakazu, Seiya Kobatake y Masahiro Irie. "Absolute asymmetric photocyclization in chiral diarylethene co-crystals with octafluoronaphthalene". Chem. Commun., n.º 3 (2008): 335–37. http://dx.doi.org/10.1039/b713694c.

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22

Wu, Guanzhao, Yangxue Liu, Zhen Yang, Nandakumar Katakam, Hossein Rouh, Sultan Ahmed, Daniel Unruh, Kazimierz Surowiec y Guigen Li. "Multilayer 3D Chirality and Its Synthetic Assembly". Research 2019 (27 de junio de 2019): 1–11. http://dx.doi.org/10.34133/2019/6717104.

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3D chirality of sandwich type of organic molecules has been discovered. The key element of this chirality is characterized by three layers of structures that are arranged nearly in parallel fashion with one on top and one down from the center plane. Individual enantiomers of these molecules have been fully characterized by spectroscopies with their enantiomeric purity measured by chiral HPLC. The absolute configuration was unambiguously assigned by X-ray diffraction analysis. This is the first multilayer 3D chirality reported and is anticipated to lead to a new research area of asymmetric synthesis and catalysis and to have a broad impact on chemical, medicinal, and material sciences in future.

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23

Hintermann, Lukas, Mauro Perseghini y Antonio Togni. "Development of the titanium–TADDOLate-catalyzed asymmetric fluorination of β-ketoesters". Beilstein Journal of Organic Chemistry 7 (17 de octubre de 2011): 1421–35. http://dx.doi.org/10.3762/bjoc.7.166.

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Titanium-based Lewis acids catalyze the α-fluorination of β-ketoesters by electrophilic N–F-fluorinating reagents. Asymmetric catalysis with TADDOLato–titanium(IV) dichloride (TADDOL = α,α,α',α'-tetraaryl-(1,3-dioxolane-4,5-diyl)-dimethanol) Lewis acids produces enantiomerically enriched α-fluorinated β-ketoesters in up to 91% enantiomeric excess, with either F–TEDA (1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate)) in acetonitrile solution or NFSI (N-fluorobenzenesulfonimide) in dichloromethane solution as fluorinating reagents. The effects of various reaction parameters and of the TADDOL ligand structure on the catalytic activity and enantioselectivity were investigated. The absolute configuration of several fluorination products was assigned through correlation. Evidence for ionization of the catalyst complex by chloride dissociation, followed by generation of titanium β-ketoenolates as key reaction intermediates, was obtained. Based on the experimental findings, a general mechanistic sketch and a steric model of induction are proposed.

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24

Wang, Jocelyn, Erica Benedetti, Lucas Bethge, Stefan Vonhoff, Sven Klussmann, Jean-Jacques Vasseur, Janine Cossy, Michael Smietana y Stellios Arseniyadis. "DNA vs. Mirror-Image DNA: A Universal Approach to Tune the Absolute Configuration in DNA-Based Asymmetric Catalysis". Angewandte Chemie International Edition 52, n.º 44 (12 de septiembre de 2013): 11546–49. http://dx.doi.org/10.1002/anie.201306232.

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25

Charlton, James L., Guy L. Plourde y Glenn H. Penner. "Asymmetric induction in Diels–Alder reactions of α-alkoxyorthoquinodimethanes". Canadian Journal of Chemistry 67, n.º 6 (1 de junio de 1989): 1010–14. http://dx.doi.org/10.1139/v89-153.

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It has been shown that dienophiles cycloadd selectively to one face of o-quinodimethanes (o-QDMs) bearing chiral α-alkoxy groups. The face selectivity (diastereoselectivity) increases for the series of chiral groups -OCH(Ph)CH3, -OCH(Ph)CH(CH3)2, and -OCH(Ph)C(CH3)3. A similar effect on the face selectivity of the Diels–Alder reactions of chiral alkoxy vinyl ethers for the same series of chiral groups has been noted previously by others. A mechanism has been proposed to explain the face selectivity in the cycloaddition reactions of the alkoxy o-QDMs. Abinitio molecular orbital calculations with geometry optimization on vinyl 1-phenylethyl ether to determine its lowest energy conformations support the proposed mechanism. The absolute stereochemistries of the o-QDM cycloadducts have been determined to verify the predictions of the model. Keywords: o-quinodimethanes, asymmetric, Diels–Alder, cycloaddition.

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26

Wang, Jocelyn, Erica Benedetti, Lucas Bethge, Stefan Vonhoff, Sven Klussmann, Jean-Jacques Vasseur, Janine Cossy, Michael Smietana y Stellios Arseniyadis. "DNA vs. Mirror-Image DNA: A Universal Approach to Tune the Absolute Configuration in DNA-Based Asymmetric Catalysis". Angewandte Chemie 125, n.º 44 (12 de septiembre de 2013): 11760–63. http://dx.doi.org/10.1002/ange.201306232.

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27

Dokli, Irena, Radek Pohl, Blanka Klepetářová y Ullrich Jahn. "First total synthesis of ent-asperparaline C and assignment of the absolute configuration of asperparaline C". Chemical Communications 55, n.º 27 (2019): 3931–34. http://dx.doi.org/10.1039/c9cc00945k.

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28

Fu, Tai Y., Zhaoqing Liu, John R. Scheffer y James Trotter. "Supramolecular photochemistry of crystalline host-guest assemblies: absolute asymmetric photorearrangement of the host component". Journal of the American Chemical Society 115, n.º 25 (diciembre de 1993): 12202–3. http://dx.doi.org/10.1021/ja00078a084.

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29

Yamamoto, Satoshi, Kenji Matsuda y Masahiro Irie. "Cover Picture: Absolute Asymmetric Photocyclization of a Photochromic Diarylethene Derivative in Single Crystals (Angew. Chem. Int. Ed. 14/2003)". Angewandte Chemie International Edition 42, n.º 14 (11 de abril de 2003): 1551. http://dx.doi.org/10.1002/anie.200390373.

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30

Shustov, G. V., S. V. Varlamov, I. I. Chervin, A. E. Aliev, R. G. Kostyanovskii, D. Kim y Arvi Rauk. "Asymmetric nitrogen. 72. Geminal systems. 46. N-Chlorooxaziridines: optical activation, absolute configuration, and chiroptical properties". Journal of the American Chemical Society 111, n.º 12 (junio de 1989): 4210–15. http://dx.doi.org/10.1021/ja00194a009.

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31

Nakai, Hidetaka, Mayu Hatake, Yousuke Miyano y Kiyoshi Isobe. "The absolute asymmetric photoisomerization of a photochromic dithionite complex in chiral crystals". Chemical Communications, n.º 19 (2009): 2685. http://dx.doi.org/10.1039/b901756a.

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32

Cheng, Maosheng, Qiang Li, Bin Lin, Yu Sha, Jinhong Ren, Yan He, Qinghe Wang, Huiming Hua y Kenneth Ruud. "Assignment of the absolute configuration of (−)-linarinic acid by theoretical calculation and asymmetric total synthesis". Tetrahedron: Asymmetry 17, n.º 2 (enero de 2006): 179–83. http://dx.doi.org/10.1016/j.tetasy.2005.11.029.

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33

Fuglseth, Erik, Eirik Sundby, Per Bruheim y Bård Helge Hoff. "Asymmetric reduction using (R)-MeCBS and determination of absolute configuration of para-substituted 2-fluoroarylethanols". Tetrahedron: Asymmetry 19, n.º 16 (agosto de 2008): 1941–46. http://dx.doi.org/10.1016/j.tetasy.2008.07.019.

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34

Pinedo-Rivilla, Cristina, Mariana Carrara Cafêu, Josefina Aleu Casatejada, Ângela Regina Araujo y Isidro G. Collado. "Asymmetric microbial reduction of ketones: absolute configuration of trans-4-ethyl-1-(1S-hydroxyethyl)cyclohexanol". Tetrahedron: Asymmetry 20, n.º 23 (diciembre de 2009): 2666–72. http://dx.doi.org/10.1016/j.tetasy.2009.11.001.

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35

Charlton, James L. "Diastereoselectivity and asymmetric induction in the Diels–Alder reaction of o-quinodimethanes". Canadian Journal of Chemistry 64, n.º 4 (1 de abril de 1986): 720–25. http://dx.doi.org/10.1139/v86-116.

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The extent of asymmetric induction in the bimolecular Diels–Alder reactions of chiral o-quinodimethanes with dimethyl fumarate, methyl acrylate, and maleic anhydride has been studied. o-Quinodimethanes with chiral α-alkoxy groups were prepared from 1-alkoxy-1,3-dihydrobenzo[c]thiophene-2,2-dioxides 4a–f or 1-alkoxy-3-phenyl-1,3-dihydrobenzo[c]thiophene-2,2-dioxides 4g–h by thermolysis. These alkoxybenzosulfones were prepared from the corresponding hydroxybenzosulfones 8 and 1-phenylethanol, 2-phenyl-1-propanol, 4-phenyl-2-butanol, 1-phenyl-2-propanol, 3,3-dimethyl-2-butanol, or 1-cyclo-hexylethanol. The 1-phenylethoxy substituent yielded the largest asymmetric induction. The absolute configurations of the major cycloadducts of methyl acrylate with the o-quinodimethanes generated from 1-(R- 1-phenylethoxy)- and 1-(S-1-phenylethoxy)-1,3-dihydrobenzo[c]thiophene-2,2-dioxides 4i and 4j have been determined to be 1S,2S-1-(R-1-phenylethoxy)- and 1R,2R-1-(S-1-phenylethoxy)-2-carbomethoxy-1,2,3,4-tetrahydronaphthalene 11i and 11j, respectively. The proposition that a chiral alkoxy substituent can block one face of the o-quinodimethane towards addition of a dienophile is discussed.

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36

Yamaguchi, Junichiro, Hideaki Kakeya, Takao Uno, Mitsuru Shoji, Hiroyuki Osada y Yujiro Hayashi. "Determination by Asymmetric Total Synthesis of the Absolute Configuration of Lucilactaene, a Cell-Cycle Inhibitor in p53-Transfected Cancer Cells". Angewandte Chemie International Edition 44, n.º 20 (13 de mayo de 2005): 3110–15. http://dx.doi.org/10.1002/anie.200500060.

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37

Nicolaou, K. C., Jae-Kyu Jung, Won Hyung Yoon, Yun He, Yong-Li Zhong y Phil S. Baran. "The Absolute Configuration and Asymmetric Total Synthesis of the CP Molecules (CP-263,114 and CP-225,917, Phomoidrides B and A)". Angewandte Chemie International Edition 39, n.º 10 (15 de mayo de 2000): 1829–32. http://dx.doi.org/10.1002/(sici)1521-3773(20000515)39:10<1829::aid-anie1829>3.0.co;2-6.

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38

Rey, Allan W., Walter A. Szarek y David B. MacLean. "Total synthesis and establishment of the absolute stereochemistry of (+)-mostueine. Addition of chiral nucleophiles to 3,4-dihydro-2-methyl-9-(p-toluenesulfonyl)-β-carbolinium iodide". Canadian Journal of Chemistry 70, n.º 12 (1 de diciembre de 1992): 2922–28. http://dx.doi.org/10.1139/v92-374.

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A highly convergent synthesis of the pentacyclic indole alkaloid (+)-mostueine (1) is described. The key step involved the coupling of the dianion derived from (1′S)-3-(1′-hydroxyethyl)-4-methylpyridine (4) with the iminium salt 3,4-dihydro-2-methyl-9-(p-toluenesulfonyl)-β-carbolinium iodide (3). Low asymmetric induction (15% de) at the C-1 position of the β-carboline ring system (C-3 of mostueine) was obtained. The nonfermenting baker's yeast-mediated reduction of 3-acetyl-4-methylpyridine provided the hydroxyethylpyridine component in acceptable yield (67%) and high optical purity (99.0% ee). This synthesis of 1 has established that the absolute stereochemistry of mostueine is (3S, 19R).

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39

Bui, Vu P., Minh Nguyen, Jeff Hansen, John Baker y Tomas Hudlicky. "Enzymatic oxidation of cyclopropylbenzene: structures of new metabolites and possible mechanistic implications". Canadian Journal of Chemistry 80, n.º 6 (1 de junio de 2002): 708–13. http://dx.doi.org/10.1139/v02-098.

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Cyclopropylbenzene was subjected to whole-cell fermentation with either Escherichia coli JM109 (pDTG601) or E. coli JM109 (pDTG602), expressing toluene dioxygenase and toluene dioxygenase dihydrodiol dehydrogenase enzymes, respectively. The corresponding metabolites, 3-cyclopropylcyclohexa-3,5-diene-1,2-diol (3) and 3-cyclopropylbenzene-1,2-diol (5) have been isolated in yields of 2.5 and 1 g L1, respectively. The absolute stereochemistry correlation for 3 is provided, along with a preliminary discussion of its potential in asymmetric synthesis. Possible mechanistic implications are indicated for the enzymatic oxygenation through the use of calculations. Experimental data are provided for all new compounds.Key words: cyclopropylbenzene, bio-oxidation, cis-diene diol, catechol, JM109 (pDTG601), JM109 (pDTG602), dioxygenase.

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40

Vaida, M., L. J. W. Shimon, J. Van Mil, K. Ernst-Cabrera, L. Addadi, L. Leiserowitz y M. Lahav. "Absolute asymmetric photochemistry using centrosymmetric single crystals. The host/guest system (E)-cinnamamide/E-cinnamic acid". Journal of the American Chemical Society 111, n.º 3 (febrero de 1989): 1029–34. http://dx.doi.org/10.1021/ja00185a036.

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41

Baglai, Iaroslav, Michel Leeman, Klaus Wurst, Bernard Kaptein, Richard M. Kellogg y Willem L. Noorduin. "The Strecker reaction coupled to Viedma ripening: a simple route to highly hindered enantiomerically pure amino acids". Chemical Communications 54, n.º 77 (2018): 10832–34. http://dx.doi.org/10.1039/c8cc06658b.

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We introduce a methodology based on a combination of the classical Strecker reaction, simple condensation and Viedma ripening, which allows absolute asymmetric synthesis of highly sterically hindered α-amino acids. As proof-of-principle, enantiomerically pure unnatural α-amino acids tert-leucine and α-(1-adamantyl)glycine have been obtained.

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42

Sakamoto, Masami, Shuichiro Kobaru, Takashi Mino y Tsutomu Fujita. "Absolute asymmetric synthesis by nucleophilic carbonyl addition using chiral crystals of achiral amides". Chem. Commun., n.º 8 (2004): 1002–3. http://dx.doi.org/10.1039/b315729f.

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43

Huber, Dominik y Antonio Mezzetti. "Chiral monodentate phosphoramidite ligands control the absolute configuration at pseudotetrahedral ruthenium: asymmetric catalytic cyclopropanation of olefins". Tetrahedron: Asymmetry 15, n.º 14 (julio de 2004): 2193–97. http://dx.doi.org/10.1016/j.tetasy.2004.05.040.

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44

McConnell, Oliver, Alvin Bach, Carl Balibar, Neal Byrne, Yanxuan Cai, Guy Carter, Michael Chlenov et al. "Enantiomeric separation and determination of absolute stereochemistry of asymmetric molecules in drug discovery—Building chiral technology toolboxes". Chirality 19, n.º 9 (2007): 658–82. http://dx.doi.org/10.1002/chir.20399.

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45

Génisson, Yves, Valérie Maraval, Remi Chauvin, Dymytrii Listunov, Etienne Joly, Pauline Rullière, Hafida Gaspard y Vania Bernardes-Génisson. "From Natural to Artificial Antitumor Lipidic Alkynylcarbinols: Asymmetric Synthesis, Enzymatic Resolution, and Refined SARs". Synthesis 50, n.º 16 (20 de julio de 2018): 3114–30. http://dx.doi.org/10.1055/s-0037-1610006.

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Among acetylenic natural products, chiral lipidic alkynylcarbinol (LAC) metabolites, mostly extracted from marine sponges, have revealed a broad spectrum of biological activities, in particular, remarkable antitumor cytotoxicity. With reference to one of the simplest natural representatives, [(S)-eicos-(4E)-en-1-yn-3-ol], and a given cancer cell line (HCT116), combined extensive efforts in chemical synthesis (relying on the use of a large chemical toolbox) and biological analysis (in vitro tests), have provided systematic structure–activity relationships (SARs) where the initially selected four structural parameters appear as independent principal components: (i) and (ii) the sp/sp2 content and extent of the terminal and internal unsaturations adjacent to the carbinol center, (iii) the absolute configuration of the latter, (iv) the length of the n-aliphatic backbone. Two key criteria have also been established regarding the functional alkynylcarbinol pharmacophore: the alkynylcarbinol unit must be both secondary and terminal (i.e., substituted by a short ethynyl or ethenyl C2 group). This review is intended to provide a further illustration of the value of a simple rational approach for drug design, and to act as a benchmark for future optimization of LACs as antitumor agents.1 Introduction2 2C2-Unsaturated Pharmacophore Candidates2.1 Alkenylalkynylcarbinols (AACs)2.2 Dialkynylcarbinols (DACs or DACys)2.3 Alkynylalkenylcarbinols (iso-AACs) and Dialkenylcarbinols (DACes)2.4 Oxidation-Protected Dialkynylcarbinols and Dialkynylketones2.5 Fluorophore-Labeled Lipidic Dialkynylcarbinols3 C2/C3-Unsaturated Pharmacophore Candidates3.1 Cyclopropylalkynylcarbinols (CACs)3.2 Allenylalkynylcarbinols (AllACs)4 C2/C4- and 3C2-Unsaturated Pharmacophore Candidates4.1 Butadiynylalkynylcarbinols (BACs)4.2 Trialkynylcarbinols (TACs)5 Double-AC-Headed Pharmacophore Candidates6 Screening on the Lipidic Chain Length7 Conclusion

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46

Ohrai, Kazuhiko, Kazuhiro Kondo, Mikiko Sodeoka y Masakatsu Shibasaki. "Effects of Solvents and Additives in the Asymmetric Heck Reaction of Alkenyl Triflates: Catalytic Asymmetric Synthesis of Decalin Derivatives and Determination of the Absolute Stereochemistry of (+)-Vernolepin". Journal of the American Chemical Society 116, n.º 26 (diciembre de 1994): 11737–48. http://dx.doi.org/10.1021/ja00105a014.

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47

Bucciarelli, M., A. Forni, I. Moretti, F. Prati y G. Torre. "Substituent Effect on the Absolute Stereochemistry of the Asymmetric Reduction of Fluorine-Containing β-Diketones by Bakers' Yeast". Biocatalysis 9, n.º 1-4 (enero de 1994): 313–20. http://dx.doi.org/10.3109/10242429408992130.

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48

Rauk, Arvi, Thomas Eggimann, Helmut Wieser, Gennadii V. Shustov y Danya Yang. "The vibrational circular dichroism spectra of 2-methylaziridine: dominance of the asymmetric centre at nitrogen". Canadian Journal of Chemistry 72, n.º 3 (1 de marzo de 1994): 506–13. http://dx.doi.org/10.1139/v94-073.

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The experimental VCD spectrum of (2R)-2-methylaziridine has been measured in the region 800–1500 cm−1. The ab initio implementation of the Vibronic Coupling Theory (VCT) of Nafie and Freedman, using the 6-31G*(0.3) basis set, in the common origin and distributed origin gauges and with uniformly and optimally scaled quantum mechanical force fields, is used to investigate the chiroptical properties. VCD spectra are computed for both cis and trans invertomers. The predicted VCD spectrum of 2-methylaziridine (the equilibrium mixture) is dominated by that of the trans diastereomer, not simply because of its greater abundance but because the rotatory strengths of many absorptions in the mid-IR are oppositely signed and of similar magnitude in the two invertomers which differ in absolute configuration at nitrogen. The VCD spectrum of 2-methylaziridine is compared in detail to that of 2-methyloxirane. In the region of the methyl group deformations and CH2 scissor, the theoretical (R)-2-methyloxirane VCD spectrum displays a much closer similarity to the cis-(2R)-2-methylaziridine than to the trans diastereomer.

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49

Roy, René y Allan W. Rey. "Controlled diastereoselection in 2-lithio-1,3-dithiane additions onto α-substituted γ-lactols. Model studies toward bryostatins from (R)-pantolactone". Canadian Journal of Chemistry 69, n.º 1 (1 de enero de 1991): 62–69. http://dx.doi.org/10.1139/v91-009.

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Homochiral α-substituted γ-lactols 3 and 4 derived from (R)-pantolactone 1 were used in 2-lithio-1,3-dithiane additions to afford very high controls in diastereoselectivities arising from 1,2-asymmetric inductions. Thus non-chelation controlled nucleophilic addition on 3 gave the anti diastereomer 5 as the major product (92% de), while the chelation controlled addition on 4 furnished the syn diastereomer 7 (96% de) as the almost exclusive product. The stereochemical outcomes of these reactions were proven unambiguously by locking the conformation of the syn- and anti-triol adducts 7 and 8 through their respective acetonides and by nuclear Overhauser enhancement measurements. The lack of 1,3-dioxolane formation in the case of the anti-triol 8 was taken as a further confirmation of the absolute configuration at the newly created stereocenter. Key words: byrostatin, pantolactone, α-hydroxylactol, dithiane.

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50

Shibata, Takanori, Kimiko Iwahashi, Tsuneomi Kawasaki y Kenso Soai. "Chiral secondary alcohol-induced asymmetric autocatalysis: correlation between the absolute configuration of the chiral initiators and the product". Tetrahedron: Asymmetry 18, n.º 15 (agosto de 2007): 1759–62. http://dx.doi.org/10.1016/j.tetasy.2007.07.030.

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