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Artículos de revistas sobre el tema "Chemoselective Transformation"

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Publicado: 18 de mayo de 2024

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1

Luo, Renshi, Yanping Xia, Lu Ouyang, Jianhua Liao y Xiao Yang. "Chemoselective Transfer Hydrogenation of α,β-Unsaturated Ketones Catalyzed by Iridium Complexes". SynOpen 05, n.º 01 (enero de 2021): 36–42. http://dx.doi.org/10.1055/s-0040-1706022.

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AbstractEfficient chemoselective transfer hydrogenation of the C=C bond of α,β-unsaturated ketones has been developed, using the iridium complexes containing pyridine-imidazolidinyl ligands as catalysts and formic acid as a hydrogen source. In comparison with organic solvents or H2O as solvent, the mixed solvents of H2O and MeOH are critical for a high catalytic chemoselective transformation. This chemoselective transfer hydrogenation can be carried out in air, which is operationally simple, allowing a wide variety of α,β-unsaturated substrates with different functional groups (electron-donating and electron-withdrawing substituents) leading to chemoselective transfer hydrogenation in excellent yields. The practical application of this protocol is demonstrated by a gram-scale transformation.
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2

Trader, Darci J. y Erin E. Carlson. "Chemoselective hydroxyl group transformation: an elusive target". Molecular BioSystems 8, n.º 10 (2012): 2484. http://dx.doi.org/10.1039/c2mb25122a.

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3

Wójtowicz-Rajchel, Hanna y Marcin Kaźmierczak. "Chemo-, regio-, and stereoselectivity in 1,3-dipolar cycloaddition of piperine with nitrones. A cycloadditive route to aminoalcohols". New Journal of Chemistry 44, n.º 15 (2020): 6015–25. http://dx.doi.org/10.1039/c9nj06442g.

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4

Yu, Sifan, Jinzhou Chen, Gengxin Liu, Jinping Lei, Wenhao Hu y Huang Qiu. "A gold(i)-catalysed chemoselective three-component reaction between phenols, α-diazocarbonyl compounds and allenamides". Chemical Communications 56, n.º 11 (2020): 1649–52. http://dx.doi.org/10.1039/c9cc09470a.

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A gold(i)-catalysed highly chemoselective three-component reaction of phenols, α-diazocarbonyl compounds and allenamides is presented. This transformation features mild reaction conditions, high functional group tolerance, and broad applicability.
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5

Kuila, Bilash, Yogesh Kumar, Dinesh Mahajan, Kapil Kumar, Prabhpreet Singh y Gaurav Bhargava. "A facile and chemoselective synthesis of 1,4-benzodiazepin-2-ones and dienyl thiazolidin-4-ones". RSC Advances 6, n.º 62 (2016): 57485–89. http://dx.doi.org/10.1039/c6ra10021j.

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A chemoselective synthesis of novel 1,4-benzodiazepin-2-ones and dienyl thiazolidin-4-one carboxylates in excellent yields by ring transformation reactions of functionally decorated 2-azetidin-3-thiazolidin-4-ones is reported.
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6

Panwar, Rahul, Shally Shally, Ranjay Shaw, Amr Elagamy y Ramendra Pratap. "Chemoselective synthesis of m-teraryls through ring transformation of 2H-pyran-2-ones by 2-(1-arylethylidene)-malononitriles". Organic & Biomolecular Chemistry 16, n.º 46 (2018): 8994–9002. http://dx.doi.org/10.1039/c8ob02370k.

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7

Ma, Haojie, Xiaoqiang Zhou, Zhenzhen Zhan, Daidong Wei, Chong Shi, Xingxing Liu y Guosheng Huang. "Copper-catalyzed transformation of ketones to amides via C(CO)–C(alkyl) bond cleavage directed by picolinamide". Organic & Biomolecular Chemistry 15, n.º 35 (2017): 7365–68. http://dx.doi.org/10.1039/c7ob01636k.

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8

Laulhé, Sébastien, Sadakatali S. Gori y Michael H. Nantz. "A Chemoselective, One-Pot Transformation of Aldehydes to Nitriles". Journal of Organic Chemistry 77, n.º 20 (10 de octubre de 2012): 9334–37. http://dx.doi.org/10.1021/jo301133y.

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9

Bergueiro, Julián, Javier Montenegro, Carlos Saá y Susana López. "One-step chemoselective conversion of tetrahydropyranyl ethers to silyl-protected alcohols". RSC Adv. 4, n.º 28 (2014): 14475–79. http://dx.doi.org/10.1039/c4ra00655k.

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A novel chemoselective one-pot transformation of acetals to silyl ethers is reported. Free hydroxyls, double bonds and triple bonds are unaffected in optimal reaction conditions. This practical, inexpensive protocol allows the selective replacement of acetal-forming protecting groups with silyl groups in a single step under mild conditions.
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10

Wang, Dawei, Yanwei Zhang, Rong Cai y Xiaodong Shi. "Triazole–Au(I) complex as chemoselective catalyst in promoting propargyl ester rearrangements". Beilstein Journal of Organic Chemistry 7 (25 de julio de 2011): 1014–20. http://dx.doi.org/10.3762/bjoc.7.115.

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Triazole–Au (TA–Au) catalysts were employed in several transformations involving propargyl ester rearrangement. Good chemoselectivity was observed, which allowed the effective activation of the alkyne without affecting the reactivity of the allene ester intermediates. These results led to the investigation of the preparation of allene ester intermediates with TA–Au catalysts under anhydrous conditions. As expected, the desired 3,3-rearrangement products were obtained in excellent yields (generally >90% yields with 1% loading). Besides the typical ester migrating groups, carbonates and carbamates were also found to be suitable for this transformation, which provided a highly efficient, practical method for the preparation of substituted allenes.
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11

Alizadeh, Abdolali, Behnaz Farajpour y Mojtaba Khanpour. "Efficient Synthesis of 7,8-Dihydro-6H-benzo[c]chromen-6-one Derivatives by Base-Mediated Chemoselective Annulation of Alkylidene Malononitriles with α,β-Unsaturated Coumarins". Synlett 32, n.º 07 (22 de enero de 2021): 697–700. http://dx.doi.org/10.1055/s-0040-1706012.

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AbstractAn efficient and chemoselective synthesis of biologically valuable 7,8-dihydro-6H-benzo[c]chromen-6-ones is described. In this method, neither a metal catalyst nor expensive starting materials are needed, and the products can be purified by simple filtration and washing with EtOH. Readily available starting materials, green and mild conditions, synthetically useful yields, and operational simplicity are some highlighted advantages of this unprecedented transformation.
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12

Laulhe, Sebastien, Sadakatali S. Gori y Michael H. Nantz. "ChemInform Abstract: A Chemoselective, One-Pot Transformation of Aldehydes to Nitriles." ChemInform 44, n.º 6 (5 de febrero de 2013): no. http://dx.doi.org/10.1002/chin.201306037.

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13

Sahoo, Santosh K., Nilufa Khatun, Anupal Gogoi, Arghya Deb y Bhisma K. Patel. "Cu(ii) catalysed chemoselective oxidative transformation of thiourea to thioamidoguanidine/2-aminobenzothiazole". RSC Adv. 3, n.º 2 (2013): 438–46. http://dx.doi.org/10.1039/c2ra22240j.

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14

Geng, Hui y Pei-Qiang Huang. "Versatile and chemoselective transformation of aliphatic and aromatic secondary amides to nitriles". Tetrahedron 71, n.º 23 (junio de 2015): 3795–801. http://dx.doi.org/10.1016/j.tet.2015.03.094.

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15

Wang, Xing, Rui-Xi Chen, Zeng-Feng Wei, Chen-Yang Zhang, Hai-Yang Tu y Ai-Dong Zhang. "Chemoselective Transformation of Diarylethanones to Arylmethanoic Acids and Diarylmethanones and Mechanistic Insights". Journal of Organic Chemistry 81, n.º 1 (15 de diciembre de 2015): 238–49. http://dx.doi.org/10.1021/acs.joc.5b02506.

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16

Chen, Hang, Jian-Liang Ye y Pei-Qiang Huang. "Chemoselective direct reductive trifluoromethylation of amides: a flexible access to functionalized α-trifluoromethylamines". Organic Chemistry Frontiers 5, n.º 6 (2018): 943–47. http://dx.doi.org/10.1039/c7qo01031a.

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17

Suárez-Castillo, Oscar R., Manuel García-Velgara, Martha S. Morales-Ríos y Pedro Joseph-Nathan. "Chemoselective intramolecular annulation of 3-alkylindolines into dihydro or tetrahydrofuro[2,3-b]indoles". Canadian Journal of Chemistry 75, n.º 7 (1 de julio de 1997): 959–64. http://dx.doi.org/10.1139/v97-115.

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3-Alkyl-2-hydroxyindolines, conveniently prepared from 2-hydroxyindolenines and a Grignard reagent, cyclize in the aprotic solvent tetrahydrofuran to afford tetrahydro-3-cyano-2-oxofuro[2,3-b]indoles, while in the protic solvent methanol the chemoselectivity changed to give dihydro-2-amino-3-carbomethoxyfuro[2,3-b]indoles. The steric effect of the alkyl group on the reactivity of 3-alkyl-2-hydroxyindolines is discussed for both processes. The ring transformation of tetrahydro-3-cyano-2-oxofuro[2,3-b]indoles into dihydro-2-amino-3-carbomethoxyfuro[2,3-b]indoles via γ-lactone imines is also discussed. Keywords: furo[2,3-b]indoles, α-cyano-γ-lactones, chemoselectivity, ring transformation, β-enamino esters.
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18

Legault, Claude, Robin Dagenais y Antoine Lauriers. "Iodine(III)-Mediated Oxidative Hydrolysis of Haloalkenes: Investigation of the Effect of Iodine(III) Reagents". Synthesis 49, n.º 13 (7 de junio de 2017): 2928–32. http://dx.doi.org/10.1055/s-0036-1588439.

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The iodine(III)-mediated oxidative transposition of vinyl halides to the corresponding α-halo ketones has been recently reported. The method is high yielding and offers good substrate scope. The investigation of other iodine(III) reagents to promote this reaction is described. The newly developed protocol reduces the number of waste products formed in the synthetic transformation. A structure–reactivity relationship study of numerous [hydroxy(tosyloxy)iodo]arenes toward haloalkenes is reported. The results highlight the challenge of obtaining a chemoselective reaction using these reagents.
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19

Salgado, Mateo M., Alejandro Manchado, Carlos T. Nieto, David Díez y Narciso M. Garrido. "Asymmetric Synthesis of 2,3,6-Trisubstituted Piperidines via Baylis–Hillman Adducts and Lithium Amide through Domino Reaction". Synlett 31, n.º 06 (24 de septiembre de 2019): 600–604. http://dx.doi.org/10.1055/s-0039-1690990.

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A convenient asymmetric synthesis of methyl (2S,3S,6R)-6-(4-fluorophenyl)-2-(4-hydroxyphenyl)-piperidine-3-carboxylate is described, starting from Baylis–Hillman adducts. The route involves a domino process: allylic acetate rearrangement, stereoselective Ireland–Claisen rearrangement and asymmetric Michael addition, which provides a δ-amino acid derivative with full stereochemical control. A subsequent chemoselective transformation of one of the side-chain groups allows an effective cyclization leading to biologically interesting polysubstituted piperidines in which the 2,6-aryl groups could be attached sequentially.
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20

Vallée, M. Robert J., Paul Majkut, Ina Wilkening, Christoph Weise, Gregor Müller y Christian P. R. Hackenberger. "Staudinger-Phosphonite Reactions for the Chemoselective Transformation of Azido-Containing Peptides and Proteins". Organic Letters 13, n.º 20 (21 de octubre de 2011): 5440–43. http://dx.doi.org/10.1021/ol2020175.

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21

Jiang, X., K. Kulbitski, G. Nisnevich y M. Gandelman. "Enantioselective assembly of tertiary stereocenters via multicomponent chemoselective cross-coupling of geminal chloro(iodo)alkanes". Chemical Science 7, n.º 4 (2016): 2762–67. http://dx.doi.org/10.1039/c5sc04378f.

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22

Suzuki, Takeshi y Takeshi Oriyama. "A Novel and Chemoselective Transformation of Alcohol Silyl Ethers into the Corresponding Tetrahydropyranyl Ethers". Synthesis 2001, n.º 04 (2001): 0555–58. http://dx.doi.org/10.1055/s-2001-12343.

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23

Geng, Hui y Pei-Qiang Huang. "ChemInform Abstract: Versatile and Chemoselective Transformation of Aliphatic and Aromatic Secondary Amides to Nitriles." ChemInform 46, n.º 37 (27 de agosto de 2015): no. http://dx.doi.org/10.1002/chin.201537050.

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24

Sahoo, Santosh K., Nilufa Khatun, Anupal Gogoi, Arghya Deb y Bhismar K. Patel. "ChemInform Abstract: Cu(II) Catalyzed Chemoselective Oxidative Transformation of Thiourea to Thioamidoguanidine/2-Aminobenzothiazole." ChemInform 44, n.º 21 (2 de mayo de 2013): no. http://dx.doi.org/10.1002/chin.201321148.

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25

Huo, Zhibao, Jiefeng Xiao, Dezhang Ren, Fangming Jin, Tian Wang y Guodong Yao. "Chemoselective synthesis of propionic acid from biomass and lactic acid over a cobalt catalyst in aqueous media". Green Chemistry 19, n.º 5 (2017): 1308–14. http://dx.doi.org/10.1039/c6gc03036j.

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26

McCullough, Richard D. y Shawn P. Williams. "A Dramatic Conformational Transformation of a Regioregular Polythiophene via a Chemoselective, Metal-Ion Assisted Deconjugation". Chemistry of Materials 7, n.º 11 (noviembre de 1995): 2001–3. http://dx.doi.org/10.1021/cm00059a004.

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27

Kotsuki, Hiyoshizo, Takeshi Ohishi y Tomohiro Araki. "A new facile method for the chemoselective reductive transformation of azides to N-(tert-butoxycarbonyl)amines". Tetrahedron Letters 38, n.º 12 (marzo de 1997): 2129–32. http://dx.doi.org/10.1016/s0040-4039(97)00324-9.

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28

Suzuki, Takeshi y Takeshi Oriyama. "ChemInform Abstract: A Novel and Chemoselective Transformation of Alcohol Silyl Ethers into the Corresponding Tetrahydropyranyl Ethers." ChemInform 32, n.º 29 (25 de mayo de 2010): no. http://dx.doi.org/10.1002/chin.200129076.

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29

Adair, Jennifer E., Christopher R. Burtner y Hans-Peter Kiem. "Maintenance of Leukocyte Telomere Length after Transplant and Chemoselection in Macaques with Polyclonal Gene Modified Cell Engraftment". Blood 126, n.º 23 (3 de diciembre de 2015): 3236. http://dx.doi.org/10.1182/blood.v126.23.3236.3236.

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Abstract Hematopoietic stem and progenitor cell (HSPC) gene therapy relies on stable therapeutic levels of gene-modified HSC engraftment. The variant methylguanine methyltransferase gene, P140K, can increase gene modified cells levels in vivo after administration of O6-benzylguanine (O6BG) and non-myeloablative bis-chloroethylnitrosurea (BCNU). However, the biological consequences of chemoselective pressure on HSPC are unknown. It is known that HSPC transplantation causes leukocyte telomere shortening, likely due to proliferative demand on engrafted blood progenitor cells required for hematopoietic reconstitution following myeloablative conditioning. Additionally, telomere shortening is associated with chromosomal instability preceding malignant evolution in blood cells. We and others demonstrate stable telomere length in pigtail and rhesus macaques following myeloablative transplantation of autologous lentivirus gene modified HSPCs. However, the selective pressure placed on P140K-modified HSC after O6BG/BCNU treatment may contribute to telomere attrition. To test this hypothesis, we performed a longitudinal assessment of telomere length on peripheral blood leukocytes using a quantitative PCR method in five pigtail macaques. Macaques received myeloablative total body irradiation (1020cGy) followed by infusion of autologous HSPC gene-modified with either a gammaretrovirus or a lentivirus encoding the P140K transgene. In all animals, O6BG/BCNU effectively increased the contribution of gene-modified cells in the blood. However, in two animals (J02370 and M02426), chemoselection was associated with a loss in total leukocyte telomere length. We sorted modified and non-modified cells in J02370 based on a fluorescent marker, and found that gene-modified leukocytes in animal J02370 displayed significantly shorter telomeres than the non-modified leukocytes. To determine the relative number of gene-modified clones contributing to this phenomenon, we investigated gene-modified clonal contribution over time in each of the five animals. Telomere shortening in animals J02370 and M02426 correlated temporally with emergence of clonal dominance in vivo, whereas animals displaying stable leukocyte telomere length maintained clonal diversity in vivo. In both J02370 and M02426, shorter total leukocyte telomere length was stably maintained with stable levels of the respective dominant clones for up to 1,700 days. Telomere shortening in these animals could be attributed to either increased cell division during clonal outgrowth, or to clonal selection of a progenitor that originally began with shorter telomeres. Importantly, our data suggest that chemoselective pressure on transduced HSPC does not impact telomere length in the setting of polyclonal hematopoiesis. While clonality may exert a negative effect on telomere length, this level of telomere attrition is not associated with malignant transformation or bone marrow failure in this animal model. Disclosures No relevant conflicts of interest to declare.
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30

Lezina, Olga M., Svetlana N. Subbotina, Larisa L. Frolova, Svetlana A. Rubtsova y Denis V. Sudarikov. "Synthesis and Oxidative Transformations of New Chiral Pinane-Type γ-Ketothiols: Stereochemical Features of Reactions". Molecules 26, n.º 17 (29 de agosto de 2021): 5245. http://dx.doi.org/10.3390/molecules26175245.

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Chiral γ-ketothiols, thioacetates, thiobenzoate, disulfides, sulfones, thiosulfonates, and sulfonic acids were obtained from β-pinene for the first time. New compounds open up prospects for the synthesis of other polyfunctional compounds combining a biologically active pinane fragment with various pharmacophore groups. It was shown that the syntheses of sulfanyl and sulfonyl derivatives based on 2-norpinanone are characterized by high stereoselectivity in comparison with similar reactions of pinocarvone. The conditions for the preparation of diastereomerically pure thioacetyl and thiobenzoyl derivatives based on pinocarvone, as well as for the chemoselective oxidation of γ-ketothiols with chlorine dioxide to the corresponding thiolsulfonates and sulfonic acids, were selected. The effect of the VO(acac)2 catalyst on the increase in the yields of thiosulfonates was shown. A new direction of the transformation of thiosulfonates with the formation of sulfones was revealed. In the case of pinocarvone-based sulfones, the configuration is inversed at the C2 atom. An epimerization scheme is proposed.
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31

Sakaitani, Masahiro y Yasufumi Ohfune. "Syntheses and reactions of silyl carbamates. 1. Chemoselective transformation of amino protecting groups via tert-butyldimethylsilyl carbamates". Journal of Organic Chemistry 55, n.º 3 (febrero de 1990): 870–76. http://dx.doi.org/10.1021/jo00290a015.

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32

Kenny, Niall P., Kamalraj V. Rajendran y Declan G. Gilheany. "Chemoselective reduction of the phosphoryl bond of O-alkyl phosphinates and related compounds: an apparently impossible transformation". Chemical Communications 51, n.º 92 (2015): 16561–64. http://dx.doi.org/10.1039/c5cc06389b.

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33

Okamoto, Akiko, Kazuhiro Kumeda y Noriyuki Yonezawa. "AlCl3-mediated Defluorinative Diarylhydroxylation Transformation of CF3: Chemoselective Arylation of CF3and Chlorocarbonyl Groups Attached to Aromatic Rings". Chemistry Letters 39, n.º 2 (5 de febrero de 2010): 124–25. http://dx.doi.org/10.1246/cl.2010.124.

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34

KOTSUKI, H., T. OHISHI y T. ARAKI. "ChemInform Abstract: A New Facile Method for the Chemoselective Reductive Transformation of Azides to N-(tert-Butoxycarbonyl)amines." ChemInform 28, n.º 26 (4 de agosto de 2010): no. http://dx.doi.org/10.1002/chin.199726077.

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35

Karthikeyan, Soundararajan, Radha Krishnan Shobana, Kamarajapurathu Raju Subimol, J. Helen Ratna Monica y Ayyanoth Karthik Krishna Kumar. "Azidophosphonium salt-directed chemoselective synthesis of (E)/(Z)-cinnamyl-1H-triazoles and regiospecific access to bromomethylcoumarins from Morita–Baylis–Hillman adducts". Beilstein Journal of Organic Chemistry 16 (1 de julio de 2020): 1579–87. http://dx.doi.org/10.3762/bjoc.16.130.

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The direct transformation of Morita–Baylis–Hillman (MBH) adducts into molecules of interest is a crucial process wherein allylic hydroxy-protected or halogenated MBH adducts are commonly preferred. Herein, we report an azidophosphonium salt (AzPS)-catalysed straight forward protocol for synthesising structurally demanding (E)/(Z)-cinnamyl-1H-1,2,3-triazoles and halomethylcoumarins from MBH adducts. The novel methodology, efficient catalyst, and direct utilization of MBH adducts under mild reaction conditions qualify the reported procedures as powerful synthetic tools.
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36

Bew, Sean P., Glyn D. Hiatt-Gipson, Graham P. Mills y Claire E. Reeves. "Efficient syntheses of climate relevant isoprene nitrates and (1R,5S)-(−)-myrtenol nitrate". Beilstein Journal of Organic Chemistry 12 (27 de mayo de 2016): 1081–95. http://dx.doi.org/10.3762/bjoc.12.103.

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Here we report the chemoselective synthesis of several important, climate relevant isoprene nitrates using silver nitrate to mediate a ’halide for nitrate’ substitution. Employing readily available starting materials, reagents and Horner–Wadsworth–Emmons chemistry the synthesis of easily separable, synthetically versatile ‘key building blocks’ (E)- and (Z)-3-methyl-4-chlorobut-2-en-1-ol as well as (E)- and (Z)-1-((2-methyl-4-bromobut-2-enyloxy)methyl)-4-methoxybenzene has been achieved using cheap, ’off the shelf’ materials. Exploiting their reactivity we have studied their ability to undergo an ‘allylic halide for allylic nitrate’ substitution reaction which we demonstrate generates (E)- and (Z)-3-methyl-4-hydroxybut-2-enyl nitrate, and (E)- and (Z)-2-methyl-4-hydroxybut-2-enyl nitrates (‘isoprene nitrates’) in 66–80% overall yields. Using NOESY experiments the elucidation of the carbon–carbon double bond configuration within the purified isoprene nitrates has been established. Further exemplifying our ‘halide for nitrate’ substitution chemistry we outline the straightforward transformation of (1R,2S)-(−)-myrtenol bromide into the previously unknown monoterpene nitrate (1R,2S)-(−)-myrtenol nitrate.
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37

Leonelli, Francesca, Irene Piergentili, Giulio Lucarelli, Luisa Maria Migneco y Rinaldo Marini Bettolo. "Unexpected Racemization in the Course of the Acetalization of (+)-(S)-5-Methyl-Wieland–Miescher Ketone with 1,2-Ethanediol and TsOH under Classical Experimental Conditions". International Journal of Molecular Sciences 20, n.º 24 (5 de diciembre de 2019): 6147. http://dx.doi.org/10.3390/ijms20246147.

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(+)-(S) and (−)-(R)-5-methyl-Wieland-Miescher ketone (+)-1 and (−)-1, are important synthons in the diastereo and enantioselective syntheses of biological and/or pharmacological interesting compounds. A key step in these syntheses is the chemoselective C(1)O acetalization to (+)-5 and (−)-5, respectively. Various procedures for this transformation have been described in the literature. Among them, the classical procedure based on the use of 1,2-ethanediol and TsOH in refluxing benzene in the presence of a Dean-Stark apparatus. Within our work on bioactive natural products, it occurred to us to observe the partial racemization of (+)-5 in the course of the acetalization of (+)-1 by means of the latter methodology. Aiming to investigate this drawback, which, to our best knowledge, has no precedents in the literature, we acetalized with 1,2-ethanediol and TsOH in refluxing benzene and in the presence of a Dean–Stark apparatus under various experimental conditions, enantiomerically pure (+)-1. It was found that the extent of racemization depends on the TsOH/(+)-1 and 1,2-ethanediol/(+)-1 ratios. Mechanism hypotheses for this partial and unexpected racemization are provided.
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38

Okamoto, Akiko, Kazuhiro Kumeda y Noriyuki Yonezawa. "ChemInform Abstract: AlCl3-Mediated Defluorinative Diarylhydroxylation Transformation of CF3: Chemoselective Arylation of CF3 and Chlorocarbonyl Groups Attached to Aromatic Rings." ChemInform 41, n.º 29 (24 de junio de 2010): no. http://dx.doi.org/10.1002/chin.201029101.

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39

Demeter, Fruzsina, Margaret Dah-Tsyr Chang, Yuan-Chuan Lee, Anikó Borbás y Mihály Herczeg. "An Efficient Synthesis of the Pentasaccharide Repeating Unit of Pseudomonas aeruginosa Psl Exopolysaccharide". Synlett 31, n.º 05 (19 de noviembre de 2019): 469–74. http://dx.doi.org/10.1055/s-0039-1690747.

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Pseudomonas aeruginosa is a biofilm-forming Gram-negative bacterium and a leading cause of life-threatening nosocomial infections. The polysaccharide synthesis locus (Psl) exopolysaccharide of P. aeruginosa is a key constituent of the defending bacterial biofilm layer and is a promising therapeutic target for resistant species. The Psl exopolysaccharide is built up from repeating pentasaccharide units which contain one α- and two β-mannosidic linkages, and one l-rhamnose and one d-glucose moieties. The preparation of this pentasaccharide was first described by Boons et al. in a 34-step synthesis. Based on their work, we have developed a new and effective pathway for the synthesis of the repeating pentasaccharide unit of the Psl exopolysaccharide. We have succeeded in simplifying the synthesis of the l-rhamnose and the α-selective d-mannose building blocks. Furthermore, taking advantage of a chemoselective pre-activation-based β-mannosylation, we directly prepare a thioglycoside disaccharide donor and use it in the next coupling reaction without further transformation. The pentasaccharide, in the form of a p-methoxyphenyl glycoside, is prepared in 26 steps, which is suitable for biological testing.
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40

Song, Xixi, Xinshuai Zhang, Shilei Zhang, Hao Li y Wei Wang. "Direct Transformation of Simple Enals to 3,4-Disubstituted Benzaldehydes under Mild Reaction Conditions via an Organocatalytic Regio- and Chemoselective Dimerization Cascade". Chemistry - A European Journal 18, n.º 32 (28 de junio de 2012): 9770–74. http://dx.doi.org/10.1002/chem.201201709.

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41

Sun, Xianwei, Zhenlei Song, Hongze Li y Changzheng Sun. "[1,4]‐S‐ to O‐Silyl Migration: Multicomponent Synthesis of α‐Thioketones through Chemoselective Transformation of Esters to Ketones with Organolithium Reagents". Chemistry – A European Journal 19, n.º 51 (14 de noviembre de 2013): 17589–94. http://dx.doi.org/10.1002/chem.201303459.

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42

Sun, Xianwei, Zhenlei Song, Hongze Li y Changzheng Sun. "ChemInform Abstract: [1,4]-S- to O-Silyl Migration: Multicomponent Synthesis of α-Thioketones Through Chemoselective Transformation of Esters to Ketones with Organolithium Reagents." ChemInform 45, n.º 21 (8 de mayo de 2014): no. http://dx.doi.org/10.1002/chin.201421050.

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43

Song, Xixi, Xinshuai Zhang, Shilei Zhang, Hao Li y Wei Wang. "ChemInform Abstract: Direct Transformation of Simple Enals to 3,4-Disubstituted Benzaldehydes under Mild Reaction Conditions via an Organocatalytic Regio- and Chemoselective Dimerization Cascade." ChemInform 44, n.º 3 (15 de enero de 2013): no. http://dx.doi.org/10.1002/chin.201303031.

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44

Kiss, Loránd, Márton Kardos, Csaba Vass y Ferenc Fülöp. "Application of Metathesis Reactions in the Synthesis and Transformations of Functionalized β-Amino Acid Derivatives". Synthesis 50, n.º 18 (26 de julio de 2018): 3571–88. http://dx.doi.org/10.1055/s-0036-1591600.

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Because of their biological relevance, cyclic β-amino acids have generated increasing interest and had significant impact in drug research over the past two decades. Their preparation and further functionalization towards new types of molecular entities have received large interest in synthetic and medicinal chemistry. Various types of metathesis reactions, such as ring-opening (ROM), ring-closing (RCM), or cross metathesis (CM) are used widely for access to either alicyclic β-amino acids or other densely functionalized derivatives of this group of compounds. This account intends to provide an insight into the most relevant synthetic routes to this class of derivatives with the application of metathesis reactions. The review focuses on the presentation of selective and stereocontrolled methodologies in view of versatility, robustness, limitations and efficiency.1 Introduction2 Synthesis and Transformation of Cyclic β-Amino Acids through Metathesis Reactions2.1 Synthesis of Five- and Six-Membered Cyclic β-Amino Acids by Ring-Closing Metathesis2.2 Synthesis of Five- and Six-Membered Cyclic β-Amino Acids by Cross Metathesis2.3 Synthesis of β-Amino Acids with Larger Ring Systems by Ring- Closing Metathesis2.4 Synthesis of β-Amino Acids with Condensed Ring Systems by Ring-Rearrangement Metathesis2.5 Stereocontrolled One-Step Synthesis of Functionalized Cispentacin and Transpentacin Derivatives2.5.1 Stereocontrolled Synthesis of Functionalized Cispentacin and Transpentacin Derivatives through Ring-Opening Metathesis of Norbornene β-Amino Acid Derivatives2.5.2 Stereocontrolled Synthesis of Functionalized Azetidinones and β-Amino Acid Derivatives from Condensed Ring β-Lactams by Ring-Opening Metathesis2.5.3 Carbon–Carbon Double Bond Functionalization of β-Amino Acid Derivatives and β-Lactams with α,β-Unsaturated Carbonyl Compounds through Cross Metathesis2.5.4 Synthesis of Functionalized β-Amino Acid Derivatives and β-Lactams through Chemoselective Cross Metathesis3 Conclusions and Outlook
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45

Shukla, Gaurav, Abhijeet Srivastava, Dhananjay Yadav y Maya Shankar Singh. "Copper-Catalyzed One-Pot Cross-Dehydrogenative Thienannulation: Chemoselective Access to Naphtho[2,1-b]thiophene-4,5-diones and Subsequent Transformation to Benzo[a]thieno[3,2-c]phenazines". Journal of Organic Chemistry 83, n.º 4 (26 de enero de 2018): 2173–81. http://dx.doi.org/10.1021/acs.joc.7b03092.

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46

Decker, David, Hans-Joachim Drexler, Detlef Heller y Torsten Beweries. "Homogeneous catalytic transfer semihydrogenation of alkynes – an overview of hydrogen sources, catalysts and reaction mechanisms". Catalysis Science & Technology 10, n.º 19 (2020): 6449–63. http://dx.doi.org/10.1039/d0cy01276a.

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47

Ma, Yating y Zhaohui Li. "Coupling plasmonic noble metal with TiO2 for efficient photocatalytic transfer hydrogenation: M/TiO2 (M = Au and Pt) for chemoselective transformation of cinnamaldehyde to cinnamyl alcohol under visible and 365 nm UV light". Applied Surface Science 452 (septiembre de 2018): 279–85. http://dx.doi.org/10.1016/j.apsusc.2018.04.244.

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48

Knochel, Paul, Andreas Boudier, Lars O. Bromm, Eike Hupe, Jesús A. Varela, Alain Rodriguez, Christopher Koradin, Tanasri Bunlaksananusorn, Hamid Laaziri y Frédéric Lhermitte. "Selective transformations mediated by main-group organometallics". Pure and Applied Chemistry 72, n.º 9 (1 de enero de 2000): 1699–703. http://dx.doi.org/10.1351/pac200072091699.

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Main-group organometallics are useful intermediates for the chemoselective and diastereoselective C-C bond formation. The boron-zinc exchange is a unique way for preparing chiral secondary alkylzinc reagents which are configurationally stable over a wide temperature scale. Coupled with the thermal rearrangement of tertiary organoboranes, a broad range of open-chain and cyclic polyfunctional molecules have been prepared. In addition, several examples of a diastereoselective remote C-H activation have been studied. The second part shows that the main-group metallic alkoxides such as t-BuOK can be used for the performance of catalytic reactions such as a new indole synthesis.
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49

Nolan, Steven P. y Hervé Clavier. "Chemoselective olefin metathesis transformations mediated by ruthenium complexes". Chemical Society Reviews 39, n.º 8 (2010): 3305. http://dx.doi.org/10.1039/b912410c.

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50

Tani, Yosuke, Kazunari Kuga, Tetsuaki Fujihara, Jun Terao y Yasushi Tsuji. "Copper-catalyzed C–C bond-forming transformation of CO2 to alcohol oxidation level: selective synthesis of homoallylic alcohols from allenes, CO2, and hydrosilanes". Chemical Communications 51, n.º 65 (2015): 13020–23. http://dx.doi.org/10.1039/c5cc03932k.

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Title transformation has been disclosed wherein CO2 is chemoselectively reduced to the alcohol oxidation level to provide homoallylic alcohols, with esters or other reducible functionalities on the allenes being intact.
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