- Gold N-Heterocyclic Carbene Catalysts for the Hydrofluorination of Alkynes Using Hydrofluoric Acid: Reaction Scope, Mechanistic Studies and the Tracking of Elusive Intermediates
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An efficient and chemoselective methodology deploying gold-N-heterocyclic carbene (NHC) complexes as catalysts in the hydrofluorination of terminal alkynes using aqueous HF has been developed. Mechanistic studies shed light on an in situ generated catalyst, formed by the reaction of Br?nsted basic gold pre-catalysts with HF in water, which exhibits the highest reactivity and chemoselectivity. The catalytic system has a wide alkyl substituted-substrate scope, and stoichiometric as well as catalytic reactions with tailor-designed gold pre-catalysts enable the identification of various gold species involved along the catalytic cycle. Computational studies aid in understanding the chemoselectivity observed through examination of key mechanistic steps for phosphine- and NHC-coordinated gold species bearing the triflate counterion and the elusive key complex bearing a bifluoride counterion.
- Bédard, Sandrine,Cavallo, Luigi,Falivene, Laura,Gauthier, Rapha?l,Nolan, Steven P.,Paquin, Jean-Fran?ois,Saab, Marina,Tzouras, Nikolaos V.,Van Hecke, Kristof,Zhang, Ziyun
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- INHIBITORS OF HUMAN IMMUNODEFICIENCY VIRUS REPLICATION
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A pharmaceutical composition comprising the compound of Formula Ia, Formula Ib, Formula Ic, or Formula Id, or a pharmaceutically acceptable salt thereof, is set forth. (Formula Ia), (Formula Ib), (Formula Ic), (Formula Id)
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Page/Page column 40-41
(2021/10/22)
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- INHIBITORS OF HUMAN IMMUNODEFICIENCY VIRUS REPLICATION
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A compound of Formula I, including pharmaceutically acceptable salts thereof, and compositions and methods for treating human immunodeficiency virus (HIV) infection are set forth: (I)
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Page/Page column 18-19
(2021/09/11)
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- INHIBITORS OF HUMAN IMMUNODEFICIENCY VIRUS REPLICATION
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The compound (I) and pharmaceutically acceptable salts thereof, and compositions and methods for treating human immunodeficiency virus (HIV) infection are set forth.
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Page/Page column 23; 24
(2020/08/22)
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- Tuning Regioselectivity of Wacker Oxidation in One Catalytic System: Small Change Makes Big Step
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A regioselectivity switchable aerobic Wacker-Tsuji oxidation has been developed using catalytic tert-butyl nitrite as a simple organic redox cocatalyst. By solely switching the solvent, either substituted aldehydes or ketones could be prepared under mild
- Hu, Kang-Fei,Ning, Xiao-Shan,Qu, Jian-Ping,Kang, Yan-Biao
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p. 11327 - 11332
(2018/09/06)
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- A Nucleophilic Activation of Carboxylic Acids by Proline: Oxa-Michael Addition to Methyl Vinyl Ketone under Solvent-Free Conditions
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A serendipitous nucleophilic activation of carboxylic acids by proline helped to achieve a direct hydrocarboxylation of methyl vinyl ketone at 60 °C under solvent-free conditions. A variety of carboxylic acids were used successfully in this oxa-Michael addition, affording useful 4-acyloxy-2-butanones in moderate yields. The reactions are carried out under solvent-free conditions, and the products are isolated in high purity by a simple work-up procedure without any need for column chromatographic purification, imparting a green quotient to the protocol. A heterodimeric non-covalent interaction between the amino acid and the carboxylic acid appears to be the most plausible mechanistic interpretation for the nucleophilic activation; additionally, the possible activation of the Michael acceptor by iminium ion formation presents an interesting case of proline acting as a bifunctional catalyst.
- Jha, Ajit Kumar,Inani, Heena,Easwar, Srinivasan
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supporting information
p. 1473 - 1477
(2017/07/22)
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- Ruthenium(II)-Catalyzed Hydration of Terminal Alkynes in PEG-400
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The ruthenium(II)-catalyzed hydration of terminal alkynes in PEG-400 to yield methyl ketones through Markovnikov addition of water across alkyne is reported.
- Mainkar, Prathama S.,Chippala, Venkataraju,Chegondi, Rambabu,Chandrasekhar, Srivari
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supporting information
p. 1969 - 1972
(2016/08/10)
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- An unexpected oxidation of unactivated methylene C-H using DIB/TBHP protocol
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An in situ generated hypervalent iodine species, bis(tert-butylperoxy) iodobenzene, was used as a peroxy radical source for the oxidation of unreactive, remote, and isolated alkyl (cyclic or aliphatic) esters and amides to the corresponding keto compounds under very mild conditions.
- Zhao, Yi,Yim, Wai-Leung,Tan, Chong Kiat,Yeung, Ying-Yeung
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supporting information; experimental part
p. 4308 - 4311
(2011/10/08)
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- Hepatitis C virus NS3-4A serine protease inhibitors: SAR of new P1 derivatives of SCH 503034
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Substitutions on the P1 cyclobutyl side chain of SCH 503034 were studied by introduction of hydroxyl and fluoro substituents. Additionally, effects of fluoro substitution on other P1 moieties were evaluated.
- Bogen,Arasappan,Pan,Ruan,Padilla,Saksena,Girijavallabhan,Njoroge
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scheme or table
p. 4219 - 4223
(2009/04/07)
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- Oxygenation vs iodonio substitution during the reactions of alkenylsilanes with iodosylbenzene: Participation of the internal oxy group
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Reaction of 4-acyloxybut-1-enylsilanes with iodosylbenzene in the presence of BF3·OEt2 gave 4-acyloxy-2-oxobutylsilane and 3-acyloxytetrahydrofuran-2-ylsilane via a 1,3-dioxan-2-yl cation intermediate, which is generated by participation of the acyloxy group during the electrophilic addition of iodine(iii) to the substrate. The Royal Society of Chemistry.
- Fujita, Morifumi,Lee, Hee Jin,Sugimura, Takashi,Okuyama, Tadashi
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p. 1139 - 1141
(2008/02/02)
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- Self-assembled bidentate ligands for ru-catalyzed anti-Markovnikov hydration of terminal alkynes
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(Figure Presented) In pairs: Bidentate ligands are generated by the self-assembly of monodentate ligands through complementary hydrogen bonding. A ruthenium complex bearing such self-assembled heterodimeric ligands is used as the catalyst in the regioselective hydration of terminal alkynes. FG = functional group, Piv = pivaloyl.
- Chevallier, Floris,Breit, Bernhard
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p. 1599 - 1602
(2008/02/02)
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- DIFLUOROALKENE DERIVATIVE, PEST CONTROL AGENT CONTAINING THE SAME, AND INTERMEDIATE THEREFOR
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A difluoroalkene derivative which is sufficiently effective in controlling various pests even when used in a small dose and is highly safe for crops, natural enemies to the pests, and animals; and an intermediate for the derivative. The difluoroalkene derivative is represented by the general formula: [I] wherein L1 and L2 are the same or different and each represents oxygen or sulfur; n is an integer of 2 to 8; and Q represents a 5- to 12-membered heterocyclic group having any desired heteroatom selected among nitrogen, oxygen, and sulfur.
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- Electrooxidative Fission of Carbon-Carbon Double Bond in a K2OsO2(OH)4/HIO4 Double Mediatory System
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Electrooxidation of olefins in the presence of potassium osmate (0.04 molar amount) and periodic acid (0.5 molar amount) afforded the corresponding carbon-carbon double bond cleavage products in moderate to good yields, where the turnover number of periodic acid reached ca. 3.
- Tanaka, Hideo,Kikuchi, Ryo,Baba, Masakatsu,Torii, Sigeru
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p. 2989 - 2992
(2007/10/03)
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