- Enantioselective counter-anions in photoredox catalysis: The asymmetric cation radical Diels-Alder reaction
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Control of absolute stereochemistry in radical and ion radical transformations is a major challenge in synthetic chemistry. Herein, we report the design of a photoredox catalyst system comprised of an oxidizing pyrilium salt bearing a chiral N-triflyl pho
- Morse, Peter D.,Nguyen, Tien M.,Cruz, Cole L.,Nicewicz, David A.
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Read Online
- Synthesis of two phloroglucinol derivatives with cinnamyl moieties as inhibitors of the carbonic anhydrase isozymes I and II: an in vitro study
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Two cinnamyl-substituted phloroglucinols, 4-p-methoxycinnamyl phloroglucinol (9) and 4,6-bis-p-methoxycinnamyl phloroglucinol (10) were synthesized. Two carbonic anhydrases, human carbonic anhydrase I and II (hCA I and II), were purified. Kinetic interact
- Burmao?lu, Serdar,Dilek, Esra,Y?lmaz, Ali Osman,Supuran, Claudiu T.
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Read Online
- Stereodivergent Nucleophilic Additions to Racemic β-Oxo Acid Derivatives: Fast Addition Outcompetes Stereoconvergence in the Archetypal Configurationally Unstable Electrophile
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Additions of carbon nucleophiles to racemic α-stereogenic β-oxo acid derivatives that deliver enantiomerically enriched tertiary alcohols are valuable, but uncommon. This article describes stereodivergent Cu-catalyzed borylative cyclizations of racemic β-oxo acid derivatives bearing tethered pro-nucleophilic olefins to deliver highly functionalized cyclopentanols containing four contiguous stereogenic centers. The reported protocol is applicable to a range of β-oxo acid derivatives, and the diastereomeric products are readily isolable by typical chromatographic techniques. α-Stereogenic-β-keto esters are typically thought to have extreme or spontaneous configurational fragility, but mechanistic studies for this system reveal an unusual scenario wherein productive catalysis occurs on the same time scale as background substrate racemization and completely outcompetes on-cycle epimerization, even under the basic conditions of the reaction.
- Crawford, Evan T.,De Jesús Cruz, Pedro,Johnson, Jeffrey S.,Liu, Shubin
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p. 16264 - 16273
(2021/10/21)
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- Synthesis of Enantioenriched 3,4-Disubstituted Chromans through Lewis Base Catalyzed Carbosulfenylation
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A method for the catalytic, enantioselective, carbosulfenylation of alkenes to construct 3,4-disubstituted chromans is described. Alkene activation proceeds through the intermediacy of enantioenriched, configurationally stable thiiranium ions generated from catalytic, Lewis base activation of an electrophilic sulfenylating agent. The transformation affords difficult-to-generate, enantioenriched, 3,4-disubstituted chromans in moderate to high yields and excellent enantioselectivities. A variety of substituents are compatible including electronically diverse functional groups as well as several functional handles such as aryl halides, esters, anilines, and phenols. The resulting thioether moiety is amenable to a number of functional group manipulations and transformations. Notably, the pendant sulfide was successfully cleaved to furnish a free thiol which readily provides access to most sulfur-containing functional groups which are present in natural products and pharmaceuticals.
- Denmark, Scott E.,Laverny, Aragorn,Menard, Travis
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p. 14290 - 14310
(2021/11/12)
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- Enantioselective Allenoate-Claisen Rearrangement Using Chiral Phosphate Catalysts
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Herein we report the first highly enantioselective allenoate-Claisen rearrangement using doubly axially chiral phosphate sodium salts as catalysts. This synthetic method provides access to β-amino acid derivatives with vicinal stereocenters in up to 95percent ee. We also investigated the mechanism of enantioinduction by transition state (TS) computations with DFT as well as statistical modeling of the relationship between selectivity and the molecular features of both the catalyst and substrate. The mutual interactions of charge-separated regions in both the zwitterionic intermediate generated by reaction of an amine to the allenoate and the Na+-salt of the chiral phosphate leads to an orientation of the TS in the catalytic pocket that maximizes favorable noncovalent interactions. Crucial arene-arene interactions at the periphery of the catalyst lead to a differentiation of the TS diastereomers. These interactions were interrogated using DFT calculations and validated through statistical modeling of parameters describing noncovalent interactions.
- Ellwart, Mario,Gensch, Tobias,Han, Seo-Jung,Lin, Hsin-Hui,Miró, Javier,Sigman, Matthew S.,Toste, F. Dean
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supporting information
p. 6390 - 6399
(2020/04/27)
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- Arene Trifunctionalization with Highly Fused Ring Systems through a Domino Aryne Nucleophilic and Diels–Alder Cascade
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A convenient and efficient domino aryne process was developed under transition-metal-free conditions to generate a range of tetra- and pentacyclic ring systems. This transformation was realized via a 1,2-benzdiyne through a nucleophilic and Diels–Alder reaction cascade using styrene as the diene moiety. Three new chemical bonds, namely one C?N and two C?C bonds, and two benzofused rings could be constructed concomitantly, which was made possible by distinct chemoselective control at both the 1,2-aryne and 2,3-aryne stages. Moreover, in-depth studies were carried out on the domino aryne precursors and controlling the diastereoselectivity.
- He, Jia,Jia, Zizi,Tan, Hongcheng,Luo, Xiaohua,Qiu, Dachuan,Shi, Jiarong,Xu, Hai,Li, Yang
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p. 18513 - 18518
(2019/11/19)
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- Hypervalent iodine initiated intramolecular alkene dimerisation: A stereodivergent entry to cyclobutanes
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The emergence of new methods for the stereoselective synthesis of strained carbocycles is a challenging but worthwhile endeavour. Cyclobutanes, in particular, have attracted the attention of both medicinal chemists and material scientists for their unique properties. Herein, we present a new method that allows access to highly functionalized cyclobutanes with complementary all-trans and trans-cis-trans relative stereochemistry, that could not be accessed before. This approach consists of an intramolecular dimerisation of non-conjugated dienes using an oxidative single electron transfer (SET) process, and is initiated by catalytic amounts of hypervalent iodine reagents. The potential uses of these cyclobutanes is demonstrated with selective functionalization, including the formation of diols and carboxylic acids.
- Zhu, Yuxiang,Colomer, Ignacio,Donohoe, Timothy J.
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p. 10316 - 10319
(2019/09/03)
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- Biocatalytic dynamic kinetic reductive resolution with ketoreductase from: Klebsiella pneumoniae: The asymmetric synthesis of functionalized tetrahydropyrans
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Ketoreductase from growing cells of Klebsiella pneumoniae (NBRC 3319) acts as an efficient reagent for converting racemic α-benzyl/cinnamyl substituted-β-ketoesters to the corresponding β-hydroxy esters with excellent yields and stereoselectivities (ee and de >99 %). The reactions described herein followed a biocatalytic dynamic kinetic reductive resolution (DKRR) pathway, which is reported for the first time with such substrates. It was found that the enzyme system can accept substituted mono-aryl rings with different electronic natures. In addition, it also accepts a substituted naphthyl ring and heteroaryl ring in the α-position of the parent β-ketoester. The synthesized enantiopure β-hydroxy esters were then synthetically manipulated to valuable tetrahydropyran building blocks.
- Barik, Rasmita,Halder, Joydev,Nanda, Samik
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p. 8571 - 8588
(2019/10/02)
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- Ruthenium-catalyzed enantioselective C-H functionalization: A practical access to optically active indoline derivatives
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Ru(II)-catalyzed enantioselective C-H activation/hydroarylation has been developed for the first time, allowing for highly enantioselective synthesis of indoline derivatives via catalytic C-H activation. Commercially available Ru(II) arene complexes and chiral α-methylamines were employed as highly enantioselective catalysts. Based on a sterically rigidified chiral transient directing group, multisubstituted indolines were produced in up to 92% yield with 96% ee. Further transformation of the resulting 4-formylindoline enables access to an optically active tricyclic compound that is of potential biological and pharmaceutical interest.
- Li, Zhong-Yuan,Lakmal, Hetti Handi Chaminda,Qian, Xiaolin,Zhu, Zhenyu,Donnadieu, Bruno,McClain, Sarah J.,Xu, Xue,Cui, Xin
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supporting information
p. 15730 - 15736
(2019/10/11)
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- Halogen Bond Catalyzed Bromocarbocyclization
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A halogen bond catalyzed bromo-carbocyclization of N-cinnamyl sulfonamides and O-cinnamyl phenyl ethers has been developed. N-methyl 4-iodopyridinium triflate is used as the halogen-bonding organocatalyst and the reaction is highly chemoselective. This report represents the first proof-of-concept for halogen-bonding organocatalyst-promoted electrophilic halogenation. Mechanistic study suggests the autocatalytic nature of this reaction.
- Chan, Yuk-Cheung,Yeung, Ying-Yeung
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p. 3483 - 3487
(2018/02/28)
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- Discovery of novel piperonyl derivatives as diapophytoene desaturase inhibitors for the treatment of methicillin-, vancomycin- and linezolid-resistant Staphylococcus aureus infections
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Inhibition of S. aureus diapophytoene desaturase (CrtN) could serve as an alternative approach for addressing the tricky antibiotic resistance by blocking the biosynthesis of carotenoid pigment which shields the bacterium from host oxidant killing. In this study, we designed and synthesized 44 derivatives with piperonyl scaffold targeting CrtN and the structure-activity relationships (SARs) were examined extensively to bring out the discovery of 21b with potent efficacy and better hERG safety profile compared to the first class CrtN inhibitor benzocycloalkane derivative 2. Except the excellent pigment inhibitory activity against wild-type S. aureus, 21b also showed excellent pigment inhibition against four pigmented MRSA strains. In addition, H2O2 killing and human whole blood killing assays proved 21b could sensitize S. aureus to be killed under oxidative stress conditions. Notably, the murine study in vivo validated the efficacy of 21b against pigmented S. aureus Newman, vancomycin-intermediate S. aureus Mu50 and linezolid-resistant S. aureus NRS271.
- Wei, Hanwen,Mao, Fei,Ni, Shuaishuai,Chen, Feifei,Li, Baoli,Qiu, Xiaoxia,Hu, Linghao,Wang, Manjiong,Zheng, Xinyu,Zhu, Jin,Lan, Lefu,Li, Jian
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p. 235 - 251
(2018/01/17)
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- Novel Terminal Bipheny-Based Diapophytoene Desaturases (CrtN) Inhibitors as Anti-MRSA/VISR/LRSA Agents with Reduced hERG Activity
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CrtN has been identified as an attractive and druggable target for treating pigmented Staphylococcus aureus infections. More than 100 new compounds were synthesized, which target the overwhelming the defects of the CrtN inhibitor 1. Analogues 23a and 23b demonstrated a significant activity against pigmented S. aureus Newman and 13 MRSA strains (IC50 = 0.02-10.5 nM), along with lower hERG inhibition (IC50 > 30 μM, ~10-fold decrease in comparison with 1). Furthermore, 23a and 23b were confirmed to reduce the staphylococcal load in the kidney and heart in a mouse model with normal treatment deeper than pretreatment ones, comparable even with vancomycin and linezolid. Remarkably, 23a could strongly block the pigment biosynthesis of these nine multidrug-resistant MRSA strains, including excellent activity against LRSA strains and VISA strains in vivo, and all of which demonstrated that 23a has a huge potential against intractable MRSA, VISA, and LRSA issues as a therapeutic drug.
- Li, Baoli,Ni, Shuaishuai,Mao, Fei,Chen, Feifei,Liu, Yifu,Wei, Hanwen,Chen, Wenhua,Zhu, Jin,Lan, Lefu,Li, Jian
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p. 224 - 250
(2018/02/10)
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- Novel Staphyloxanthin Inhibitors with Improved Potency against Multidrug Resistant Staphylococcus aureus
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Diapophytoene desaturase (CrtN) is a potential novel target for intervening in the biosynthesis of the virulence factor staphyloxanthin. In this study, 38 1,4-benzodioxan-derived CrtN inhibitors were designed and synthesized to overwhelm the defects of leading compound 4a. Derivative 47 displayed superior pigment inhibitory activity, better hERG inhibitory properties and water solubility, and significantly sensitized MRSA strains to immune clearance in vitro. Notably, 47 displayed excellent efficacy against pigmented S. aureus Newman, Mu50 (vancomycin-intermediate MRSA, VISA), and NRS271 (linezolid-resistant MRSA, LRSA) comparable to that of linezolid and vancomycin in vivo.
- Ni, Shuaishuai,Li, Baoli,Chen, Feifei,Wei, Hanwen,Mao, Fei,Liu, Yifu,Xu, Yixiang,Qiu, Xiaoxi,Li, Xiaokang,Liu, Wenwen,Hu, Linghao,Ling, Dazheng,Wang, Manjiong,Zheng, Xinyu,Zhu, Jin,Lan, Lefu,Li, Jian
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p. 233 - 237
(2018/03/21)
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- trans-Cyclooctenes as Halolactonization Catalysts
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The strained olefins in trans-cyclooctenes serve as efficient catalysts for halolactonizations, including bromolactonizations and iodolactonizations. The trans-cyclooctene framework is essential for excellent catalytic performance, and the substituents also play important roles in determining efficiency. These results are the first demonstration of catalysis by a trans-cyclooctene.
- Einaru, Shunsuke,Shitamichi, Kenta,Nagano, Tagui,Matsumoto, Akira,Asano, Keisuke,Matsubara, Seijiro
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p. 13863 - 13867
(2018/09/27)
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- Asymmetric Cα-Alkylation of Proline via Chirality Transfers of Conformationally Restricted Proline Derivative: Application to the Total Synthesis of (-)-Amathaspiramide F
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An efficient strategy for the asymmetric synthesis of Cα-tetrasubstituted proline derivatives from proline has been established. A nitrogen-fused bicyclic system was devised to control the stereodynamics of proline. Through N-quaternizations with allylic electrophiles followed by [2,3]-rearrangements, the bicyclic proline system delivered enantioenriched Cα-tetrasubstituted prolines. This strategy was applied to the concise total synthesis of (-)-amathaspiramide F.
- Cho, Hyunkyung,Shin, Jae Eui,Lee, Seokwoo,Jeon, Hongjun,Park, Soojun,Kim, Sanghee
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p. 6121 - 6125
(2018/10/02)
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- Novel Inhibitors of Staphyloxanthin Virulence Factor in Comparison with Linezolid and Vancomycin versus Methicillin-Resistant, Linezolid-Resistant, and Vancomycin-Intermediate Staphylococcus aureus Infections in Vivo
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Our previous work (Wang et al. J. Med. Chem. 2016, 59, 4831-4848) revealed that effective benzocycloalkane-derived staphyloxanthin inhibitors against methicillin-resistant Staphylococcus aureus (S. aureus) infections were accompanied by poor water solubility and high hERG inhibition and dosages (preadministration). In this study, 92 chroman and coumaran derivatives as novel inhibitors have been addressed for overcoming deficiencies above. Derivatives 69 and 105 displayed excellent pigment inhibitory activities and low hERG inhibition, along with improvement of solubility by salt type selection. The broad and significantly potent antibacterial spectra of 69 and 105 were displayed first with normal administration in the livers and hearts in mice against pigmented S. aureus Newman, Mu50 (vancomycin-intermediate S. aureus), and NRS271 (linezolid-resistant S. aureus), compared with linezolid and vancomycin. In summary, both 69 and 105 have the potential to be developed as good antibacterial candidates targeting virulence factors.
- Ni, Shuaishuai,Wei, Hanwen,Li, Baoli,Chen, Feifei,Liu, Yifu,Chen, Wenhua,Xu, Yixiang,Qiu, Xiaoxia,Li, Xiaokang,Lu, Yanli,Liu, Wenwen,Hu, Linhao,Lin, Dazheng,Wang, Manjiong,Zheng, Xinyu,Mao, Fei,Zhu, Jin,Lan, Lefu,Li, Jian
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p. 8145 - 8159
(2017/10/18)
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- Discovery of Benzocycloalkane Derivatives Efficiently Blocking Bacterial Virulence for the Treatment of Methicillin-Resistant S. aureus (MRSA) Infections by Targeting Diapophytoene Desaturase (CrtN)
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Antivirulence strategies are now attracting interest for the inherent mechanism of action advantages. In our previous work, diapophytoene desaturase (CrtN) was identified to be an attractive and drugable target for fighting pigmented S. aureus infections. In this research, we developed a series of effective benzocycloalkane-derived CrtN inhibitors with submicromolar IC50. Analogue 8 blocked the pigment biosynthesis of three MRSA strains with a nanomolar IC50 value. Corresponding to its mode of action, 8 did not function as a bactericidal agent. 8 could sensitize S. aureus to immune clearance. In vivo, 8 was proven to be efficacious in an S. aureus Newman sepsis model and abscess formation model. For two typical MRSAs, USA400 MW2 and Mu50, 8 significantly decreased the staphylococcal loads in the liver and kidneys. Moreover, 8 showed minimal antifungal activity compared to that of NTF. In summary, 8 has the potential to be developed as a therapeutic drug, especially against intractable MRSA issues.
- Wang, Youxin,Di, Hongxia,Chen, Feifei,Xu, Yong,Xiao, Qiang,Wang, Xuehai,Wei, Hanwen,Lu, Yanli,Zhang, Lingling,Zhu, Jin,Lan, Lefu,Li, Jian
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p. 4831 - 4848
(2016/06/13)
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- Tandem Ring-Opening–Ring-Closing Metathesis for Functional Metathesis Catalysts
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Use of a tandem ring-opening–ring-closing metathesis (RORCM) strategy for the synthesis of functional metathesis catalysts is reported. Ring opening of 7-substituted norbornenes and subsequent ring-closing metathesis forming a thermodynamically stable 6-membered ring lead to a very efficient synthesis of new catalysts from commercially available Grubbs’ catalysts. Hydroxy functionalized Grubbs’ first- as well as third-generation catalysts have been synthesized. Mechanistic studies have been performed to elucidate the order of attack of the olefinic bonds. This strategy was also used to synthesize the ruthenium methylidene complex.
- Nagarkar, Amit A.,Yasir, Mohammad,Crochet, Aurelien,Fromm, Katharina M.,Kilbinger, Andreas F. M.
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p. 12343 - 12346
(2016/10/13)
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- Discovery of Potent Benzofuran-Derived Diapophytoene Desaturase (CrtN) Inhibitors with Enhanced Oral Bioavailability for the Treatment of Methicillin-Resistant Staphylococcus aureus (MRSA) Infections
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Blocking the staphyloxanthin biosynthesis process has emerged as a new promising antivirulence strategy. Previously, we first revealed that CrtN is a druggable target against infections caused by pigmented Staphylococcus aureus (S. aureus) and that naftifine was an effective CrtN inhibitor. Here, we identify a new type of benzofuran-derived CrtN inhibitor with submicromolar IC50 values that is based on the naftifine scaffold. The most potent analog, 5m, inhibits the pigment production of S. aureus Newman and three MRSA strains, with IC50 values of 0.38-5.45 nM, without any impact on the survival of four strains (up to 200 μM). Notably, compound 5m (1 μM) could significantly sensitize four strains to immune clearance and could effectively attenuate the virulence of three strains in vivo. Moreover, 5m was determined to be a weak antifungal reagent (MIC > 16 μg/mL). Combined with good oral bioavailability (F = 42.2%) and excellent safety profiles, these data demonstrate that 5m may be a good candidate for the treatment of MRSA infections.
- Wang, Youxin,Chen, Feifei,Di, Hongxia,Xu, Yong,Xiao, Qiang,Wang, Xuehai,Wei, Hanwen,Lu, Yanli,Zhang, Lingling,Zhu, Jin,Sheng, Chunquan,Lan, Lefu,Li, Jian
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p. 3215 - 3230
(2016/05/19)
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- Dialkylzinc-mediated allylic polyfluoroarylation reaction
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Abstract We present an allylic polyfluoroarylation reaction with broad substrate scope and excellent functional group tolerance, using organozinc reagents under mild conditions. A catalytic amount of triphenylphosphine oxide efficiently promotes iodine-zinc exchange reaction between polyfluoroaryl iodide and dimethylzinc, and the resulting phosphine oxide-activated polyfluoroarylzinc undergoes substitution reaction with allylic halides to afford the corresponding polyfluoroarylated products.
- Kurauchi, Daisuke,Hirano, Keiichi,Kato, Hisano,Saito, Tatsuo,Miyamoto, Kazunori,Uchiyama, Masanobu
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p. 5849 - 5857
(2015/08/03)
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- An isothiourea-catalyzed asymmetric [2,3]-rearrangement of allylic ammonium ylides
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Benzotetramisole promotes the catalytic asymmetric [2,3]-rearrangement of allylic quaternary ammonium salts (either isolated or prepared in situ from p-nitrophenyl bromoacetate and the corresponding allylic amine), generating syn-α-amino acid derivatives with excellent diastereo- and enantioselectivity (up to >95:5 dr; up to >99% ee).
- West, Thomas H.,Daniels, David S. B.,Slawin, Alexandra M. Z.,Smith, Andrew D.
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p. 4476 - 4479
(2014/04/17)
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- PRO-FRAGRANCE COMPOUNDS
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A compound is provided of Formula (I), wherein R1 represents a C3 to C20 hydrocarbon group derived from an alcohol of formula R1OH, from a formate of formula R1OCH=O, or a cinnamyl aldehyde of Formula
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Page/Page column 18; 19
(2014/12/09)
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- Copper-catalyzed nucleophilic trifluoromethylation of allylic halides: A simple approach to allylic trifluoromethylation
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Trifluoromethylation: The treatment of allylic halides with trifluoromethyltrimethylsilane in the presence of a catalytic amount of copper(I) thiophene-2-carboxylate (CuTC) gives the corresponding allylic trifluoromethylation products in good to high yields and with complete regioselectivity (see scheme). The use of THF as a solvent is crucial for obtaining good yields of product.
- Miyake, Yoshihiro,Ota, Shin-Ichi,Nishibayashi, Yoshiaki
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supporting information
p. 13255 - 13258
(2012/11/07)
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- A catalytic asymmetric chlorocyclization of unsaturated amides
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The asymmetric chlorocyclization of unsaturated amides catalyzed by (DHQD)2PHAL yields oxazoline and dihydrooxazine derivatives (see scheme). The reaction is operationally simple and employs 1-2 mol % of the commercially available (DHQD)2PHAL (hydroquinidine 1,4-phthalazinediyl diether) catalyst. Different substitution patterns of the olefin as well as aromatic and aliphatic olefin substituents are well tolerated. DCDPH=N,N-dichloro-5,5-diphenylhydantoin. Copyright
- Jaganathan, Arvind,Garzan, Atefeh,Whitehead, Daniel C.,Staples, Richard J.,Borhan, Babak
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supporting information; scheme or table
p. 2593 - 2596
(2011/05/02)
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- Finding more active antioxidants and cancer chemoprevention agents by elongating the conjugated links of resveratrol
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Resveratrol is the subject of intense research as a natural antioxidant and cancer chemopreventive agent. There has been a great deal of interest and excitement in understanding its action mechanism and developing analogs with antioxidant and cancer chemoprevention activities superior to that of the parent compound in the past decade. This work delineates that elongation of the conjugated links is an important strategy to improve the antioxidant activity of resveratrol analogs, including hydrogen atom- or electron-donating ability in homogeneous solutions and antihemolysis activity in heterogeneous media. More importantly, C3, a triene bearing 4,4′-dihydroxy groups, surfaced as an important lead compound displaying remarkably increased antioxidant, cytotoxic, and apoptosis-inducing activities compared with resveratrol.
- Tang, Jiang-Jiang,Fan, Gui-Juan,Dai, Fang,Ding, De-Jun,Wang, Qi,Lu, Dong-Liang,Li, Ran-Ran,Li, Xiu-Zhuang,Hu, Li-Mei,Jin, Xiao-Ling,Zhou, Bo
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p. 1447 - 1457
(2012/05/05)
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- Expedient access to branched allylic silanes by copper-catalysed allylic substitution of linear allylic halides
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An unprecedented copper-catalysed allylic transposition enables the regioselective synthesis of branched allylic silanes from linear allylic halides through direct C-Si bond formation.
- Vyas, Devendra J.,Oestreich, Martin
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supporting information; experimental part
p. 568 - 570
(2010/05/01)
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- A highly regio- and stereoselective formation of bicyclo[4.2.0]oct-5-ene derivatives through thermal intramolecular [2 + 2] cycloaddition of allenes
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(Chemical Equation Presented) Thermal [2 + 2] cycloaddition of allenes with an additional multiple bond is described. By simply heating the allenenes or allenynes having a three-atom tether in an appropriate solvent such as dioxane or DMF, the distal doub
- Ohno, Hiroaki,Mizutani, Tsuyoshi,Kadoh, Yoichi,Aso, Akimasa,Miyamura, Kumiko,Fujii, Nobutaka,Tanaka, Tetsuaki
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p. 4378 - 4389
(2008/02/05)
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- 1-Cinnamyl-4-(2-methoxyphenyl)piperazines: Synthesis, binding properties, and docking to dopamine (D2) and serotonin (5-HT1A) receptors
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Clinical properties of atypical antipsychotics are based on their interaction with D2 dopamine receptor and serotonin 5-HT1A and 5-HT2A receptors. As a part of our research program on new antipsychotics, we synthesized various derivatives of 1-cinnamyl-4-(2- methoxyphenyl)piperazines, and evaluated their affinities for D2, 5-HT1A, 5-HT2A, and adrenergic (α1) receptors using radioligand-binding assays. In addition, we performed docking analysis using models for the D2 and 5-HT1A receptors. All compounds exhibited low to moderate affinity to 5-HT1A and 5-HT 2A receptors, high affinity to the D2 receptor and large variability in affinities for the α1 receptor. Docking analysis indicated that the binding to D2 and 5-HT1A receptors is based on (i) interaction between protonated N1 of the piperazine ring and various aspartate residues, (ii) hydrogen bonds between various moieties of the ligand and the residues of threonine, serine, histidine or tryptophane, and (iii) edge-to-face interactions of the aromatic ring of the arylpiperazine moiety with phenylalanine or tyrosine residues. Docking data for the D 2 receptor can account for the binding properties obtained in binding assays, suggesting that the model is reliable and robust. However, docking data for the 5-HT1A receptor cannot account for actual binding properties, suggesting that further refinement of the model is required.
- Penjisevic, Jelena,Sukalovic, Vladimir,Andric, Deana,Kostic-Rajacic, Sladjana,Soskic, Vukic,Roglic, Goran
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p. 456 - 465
(2008/12/21)
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- A method for the introduction of reporter groups into moenomycin A, based on thiouronium salt chemistry
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p-Alkoxy-substituted cinnamylthiouronium salts 7, 13, 21a, and 21b reacted selectively with the 2-acylamino-1,3-cyclopentanedione unit A of moenomycin A (1) to give the corresponding 2-alkylated products 14a, 14b, 22a, and 22b. These products, depending on the pH of the solution, were either stable under the reaction conditions or they underwent retro-Claisen-type reactions. The method can be used for the attachment of reporter groups to moenomycin A for the synthesis of, for example, 25. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002).
- Buchynskyy, Andrij,Stembera, Katherina,Hennig, Lothar,Findeisen, Matthias,Giesa, Sabine,Welzel, Peter
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p. 1163 - 1174
(2007/10/03)
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- Is hole transfer involved in metalloporphyrin-catalyzed epoxidation?
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The possibility of a hole-transfer mechanism for the epoxidation of alkenes catalyzed by metalloporphyrins (MP) has been investigated. In the first approach, the results of MP-catalyzed epoxidation of a series of substrates were compared to the corresponding results of epoxidation under conditions where cation radicals are demonstrably formed (using a triarylaminium salt catalyst). In sharp contrast to the MP-catalyzed epoxidations (using M = Mn), the hole-catalyzed epoxidations do not generate carbonyl compounds and alcohols as byproducts and are rigorously stereospecific. These results are of interest primarily in that they provide support for the assumption that cation radicals can be efficiently and stereospecifically epoxidized by appropriate oxygen-transfer agents. However, the differences in product composition and stereochemistry for MP- vs hole-catalyzed epoxidation cannot be construed mechanistically to rule out a cation radical mechanism for the former, especially because the oxygen-transfer agents are different in the two reaction systems. In a second, and more rigorous, approach, a careful search for transient cation radical intermediates in MP-catalyzed epoxidations (using M = Mn and Fe) was carried out using newly developed cation radical probe reactions. Cation radical intermediates were, in fact, not detected and, if involved, must be extremely short lived (-2 s). The results of this work, taken as a whole, are reasonably construed to suggest that, even for the relatively easily ionizable alkene functionalities present in many of the probe substrates, a hole-transfer mechanism is probably not operative in MP-catalyzed epoxidations.
- Kim, Taisun,Mirafzal, Gholam A.,Liu, Jianping,Bauld, Nathan L.
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p. 7653 - 7664
(2007/10/02)
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- Synthesis of 3-(4'-Methoxy-1'-phenyl)allyl Citronellyl Ether and Related Structures
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Substituted aromatic allyl citronellyl ethers (1-4) have been prepared and structures supported by spectral data.The compounds were tested for juvenile hormone activity.
- Bhatia, M. S.,Rani, Poonam,Xavierkutty, M. C.,Lal, Jawahar
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p. 411 - 413
(2007/10/02)
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- 6- and 8?-Ringschlussreaktionen von 2-Oxaheptatrienyl-Dipolen: Synthese von 3-Vinyl-2,3-dihydrofuranen und 2,3(6,7)-Dihydrooxepinen
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The thermally induced ring expansion reactions of several butadienyloxiranes are described.The 3(E)-configurated epoxytrienes 11 are transformed predominantly into cis-3-vinyl-2,3-dihydrofurans 15, the trans-isomers 16 being formed as a minor component only with the derivatives a, c, and h.In contrast, thermolysis of the 3(Z)-butadienyloxiranes 12 leads always to a mixture of fivemembered ring products (15/16) and, additionally, dihyrooxepins (17 and 29, resp.).As mechanism of the ring expansion reactions a multistep sequence is proposed with 2-oxaheptatrienyl dipoles as intermediates, which undergo electrocyclisation with participation of either six or eight electrons leading to dihydrofurans and dihydrooxepins, resp.With relation to 1,7-cyclisation reactions of other extended dipole systems the importance of the stereochemistry in the starting materials is emphasised.
- Eberbach, Wolfgang,Trostmann, Uwe
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p. 2979 - 3003
(2007/10/02)
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