- An efficient chemoenzymatic approach towards the synthesis of rugulactone
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Rugulactone is a natural product isolated from the plant Cryptocarya rugulosa. It has shown very important biological activity as an inhibitor of the nuclear factor κB (NF-κB) activation pathway. A new chemoenzymatic approach towards the synthesis of rugu
- Tyrikos-Ergas, Theodore,Giannopoulos, Vasileios,Smonou, Ioulia
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- Regio- And Enantioselective Iridium-Catalyzed Amination of Alkyl-Substituted Allylic Acetates with Secondary Amines
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Robust air-stable cyclometalated π-allyliridium C,O-benzoates modified by (S)-tol-BINAP catalyze the reaction of secondary aliphatic amines with racemic alkyl-substituted allylic acetates to furnish products of allylic amination with high levels of enantioselectivity. Complete branched regioselectivities were observed despite the formation of more highly substituted C-N bonds.
- Jung, Woo-Ok,Yoo, Minjin,Migliozzi, Madyson M.,Zbieg, Jason R.,Stivala, Craig E.,Krische, Michael J.
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supporting information
p. 441 - 445
(2021/12/27)
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- Synthesis of Bioactive Diarylheptanoids from Alpinia officinarum and Their Mechanism of Action for Anticancer Properties in Breast Cancer Cells
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An efficient synthesis of the Alpinia officinarum-derived diarylheptanoids, viz., enantiomers of a β-hydroxyketone (1) and an α,β-unsaturated ketone (2) was developed starting from commercially available eugenol. Among these, compound 2 showed a superior
- Gamre, Sunita,Tyagi, Mrityunjay,Chatterjee, Sucheta,Patro, Birija S.,Chattopadhyay, Subrata,Goswami, Dibakar
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p. 352 - 363
(2021/03/01)
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- Selective hydroboration of equilibrating allylic azides
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The iridium(i)-catalyzed hydroboration of equilibrating allylic azides is reported to provide only the anti-Markovnikov product of alk-1-ene isomers in good yields and with good functional group tolerance.
- Liu, Ruzhang,Xu, Jun,Zhang, Yuanyuan
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supporting information
p. 8913 - 8916
(2021/09/13)
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- GPR52 Antagonist Reduces Huntingtin Levels and Ameliorates Huntington's Disease-Related Phenotypes
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GPR52 is an orphan G protein-coupled receptor (GPCR) that has been recently implicated as a potential drug target of Huntington's disease (HD), an incurable monogenic neurodegenerative disorder. In this research, we found that striatal knockdown of GPR52 reduces mHTT levels in adult HdhQ140 mice, validating GPR52 as an HD target. In addition, we discovered a highly potent and specific GPR52 antagonist Comp-43 with an IC50 value of 0.63 μM by a structure-activity relationship (SAR) study. Further studies showed that Comp-43 reduces mHTT levels by targeting GPR52 and promotes survival of mouse primary striatal neurons. Moreover, in vivo study showed that Comp-43 not only reduces mHTT levels but also rescues HD-related phenotypes in HdhQ140 mice. Taken together, our study confirms that inhibition of GPR52 is a promising strategy for HD therapy, and the GPR52 antagonist Comp-43 might serve as a lead compound for further investigation.
- Wang, Congcong,Zhang, Yu-Fang,Guo, Shimeng,Zhao, Quan,Zeng, Yanping,Xie, Zhicheng,Xie, Xin,Lu, Boxun,Hu, Youhong
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p. 941 - 957
(2020/11/30)
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- Nickel-Catalyzed C(sp3)-H Functionalization of Benzyl Nitriles: Direct Michael Addition to Terminal Vinyl Ketones
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An efficient nickel(0)-catalyzed addition of benzyl nitriles to terminal vinyl ketones via C(sp3)-H functionalization has been developed. The reaction provides a novel and efficient protocol for the synthesis of α-functionalized benzyl nitriles with a wide range of structural diversity under mild reaction conditions while obviating the use of a strong base. The work might be potentially useful toward the development of an enantioselective variant using chiral nitrogen ligands.
- Zhang, Ninghui,Zhang, Chunli,Hu, Xiaoping,Xie, Xin,Liu, Yuanhong
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supporting information
p. 6004 - 6009
(2021/07/31)
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- Stereoselective Synthesis of Oxacycles via Ruthenium-Catalyzed Atom-Economic Coupling of Propargyl Alcohols and Michael Acceptors
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Synthesis of β-hydroxyenones and its application toward development of tetrahydro-4H-pyran-4-one in an atom-economic fashion is limited. This manuscript describes a ruthenium-catalyzed atom-economic coupling of pent-2-yne-1,5-diols and Michael acceptors as an efficient route for the synthesis of β-hydroxyenones with excellent yields and high regioselectivity. The β-hydroxyenones further undergo a 6-endo trig cyclization under acid-catalyzed conditions to deliver the tetrahydro-4H-pyran-4-ones with high diastereoselectivity. An intramolecular aldol condensation under mild basic conditions and palladium-catalyzed oxidative aromatization was developed for the synthesis of hexahydro-6H-isochromen-6-ones and isochromanols, respectively, from highly substituted tetrahydro-4H-pyran-4-ones with excellent yield and diastereoselectivity. Overall, this work demonstrates the synthetic potential toward the synthesis of oxacycles like tetrahydro-4H-pyran-4-ones, hexahydro-6H-isochromen-6-ones, and isochromanols via an atom-economic catalysis.
- Bera, Nabakumar,Samanta, Shantanu,Sarkar, Debayan
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p. 16369 - 16395
(2021/11/18)
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- Concise, scalable and enantioselective total synthesis of prostaglandins
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Prostaglandins are among the most important natural isolates owing to their broad range of bioactivities and unique structures. However, current methods for the synthesis of prostaglandins suffer from low yields and lengthy steps. Here, we report a practicability-oriented synthetic strategy for the enantioselective and divergent synthesis of prostaglandins. In this approach, the multiply substituted five-membered rings in prostaglandins were constructed via the key enyne cycloisomerization with excellent selectivity (>20:1 d.r., 98% e.e.). The crucial chiral centre on the scaffold of the prostaglandins was installed using the asymmetric hydrogenation method (up to 98% yield and 98% e.e.). From our versatile common intermediates, a series of prostaglandins and related drugs could be produced in two steps, and fluprostenol could be prepared on a 20-gram scale. [Figure not available: see fulltext.]
- Zhang, Fuhao,Zeng, Jingwen,Gao, Mohan,Wang, Linzhou,Chen, Gen-Qiang,Lu, Yixin,Zhang, Xumu
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p. 692 - 697
(2021/06/01)
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- Electrochemical Nozaki-Hiyama-Kishi Coupling: Scope, Applications, and Mechanism
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One of the most oft-employed methods for C-C bond formation involving the coupling of vinyl-halides with aldehydes catalyzed by Ni and Cr (Nozaki-Hiyama-Kishi, NHK) has been rendered more practical using an electroreductive manifold. Although early studies pointed to the feasibility of such a process, those precedents were never applied by others due to cumbersome setups and limited scope. Here we show that a carefully optimized electroreductive procedure can enable a more sustainable approach to NHK, even in an asymmetric fashion on highly complex medicinally relevant systems. The e-NHK can even enable non-canonical substrate classes, such as redox-active esters, to participate with low loadings of Cr when conventional chemical techniques fail. A combination of detailed kinetics, cyclic voltammetry, and in situ UV-vis spectroelectrochemistry of these processes illuminates the subtle features of this mechanistically intricate process.
- Baran, Phil S.,Blackmond, Donna G.,Gao, Yang,Hadt, Ryan G.,Hao, Wei,Hill, David E.,McNicholas, Brendon J.,Reisman, Sarah E.,Vantourout, Julien C.
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supporting information
p. 9478 - 9488
(2021/07/19)
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- Atmospheric Oxygen Mediated Radical Hydrothiolation of Alkenes
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A mild, metal-free, atmospheric oxygen-mediated radical hydrothiolation of alkenes (and alkyne) is reported. A variety of sulfur containing motifs including alkanethiols, thiophenols and thioacids undergo an atmospheric oxygen-mediated radical hydrothiolation reaction with a plethora of alkenes in good yield with excellent functional group compatibility, typically with short reaction times to furnish a range of functionalized products. Biomolecules proved tolerant to the conditions and the procedure is robust and easily executable requiring no specialized equipment. Concise mechanistic studies confirm the process proceeds through radical intermediates in a thiol-ene reaction manifold. The methodology offers an efficient “green” approach for thiol-ene mediated “click” ligation and a milder alternative to thermally initiated hydrothiolation processes.
- McCourt, Ruairí O.,Scanlan, Eoin M.
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supporting information
p. 15804 - 15810
(2020/10/26)
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- Preparation method of alkyl nitrile compound
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The invention discloses a preparation method of an alkyl nitrile compound. Specifically, the preparation method comprises the following step: in an organic solvent, in the presence of a protective gasand under the action of a catalyst, carrying out a reduction reaction as shown in the specification on olefin as shown in a formula I, a cyanation reagent and water, wherein the alkyl nitrile compound 1 is a compound II and/or a compound III. The preparation method provided by the invention is mild in condition, can realize hydrocyanation of olefin more safely and efficiently, and has good substrate universality and functional group compatibility.
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Paragraph 0124-0126
(2020/08/18)
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- Catalytic Hydroetherification of Unactivated Alkenes Enabled by Proton-Coupled Electron Transfer
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We report a catalytic, light-driven method for the intramolecular hydroetherification of unactivated alkenols to furnish cyclic ether products. These reactions occur under visible-light irradiation in the presence of an IrIII-based photoredox catalyst, a Br?nsted base catalyst, and a hydrogen-atom transfer (HAT) co-catalyst. Reactive alkoxy radicals are proposed as key intermediates, generated by direct homolytic activation of alcohol O?H bonds through a proton-coupled electron-transfer mechanism. This method exhibits a broad substrate scope and high functional-group tolerance, and it accommodates a diverse range of alkene substitution patterns. Results demonstrating the extension of this catalytic system to carboetherification reactions are also presented.
- Knowles, Robert R.,Metrano, Anthony J.,Tsuchiya, Yuto,Tsui, Elaine
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supporting information
p. 11845 - 11849
(2020/05/22)
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- Asymmetric Synthesis of γ-Secondary Amino Alcohols via a Borrowing-Hydrogen Cascade
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The borrowing-hydrogen (or hydrogen autotransfer) process, where the catalyst dehydrogenates a substrate and formally transfers the H atom to an unsaturated intermediate, is an atom-efficient and environmentally benign transformation. Described here is an example of an asymmetric borrowing-hydrogen cascade for the formal anti-Markovnikov hydroamination of allyl alcohols to synthesize optically enriched γ-secondary amino alcohols. By exploiting the Ru-(S)-iPrPyme catalyst with minimal stereogenicity, a cascade process including dehydrogenation, conjugate addition, and asymmetric reduction was developed. The mild conditions, functional group tolerance, and broad substrate scope (54 examples) demonstrate the synthetic practicality of the catalytic system.
- Chang, Xiaoyong,Chen, Fumin,He, Dongxu,Jin, Ming Yu,Pan, Yupeng,Xing, Xiangyou,You, Yipeng
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supporting information
p. 7278 - 7283
(2020/10/02)
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- Synergistic Relay Reactions To Achieve Redox-Neutral α-Alkylations of Olefinic Alcohols with Ruthenium(II) Catalysis
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Herein, we report a ruthenium-catalyzed redox-neutral α-alkylation of unsaturated alcohols based on a synergistic relay process involving olefin isomerization (chain walking) and umpolung hydrazone addition, which takes advantage of the interaction between the two rather inefficient individual reaction steps to enable an efficient overall process. This transformation shows the compatibility of hydrazone-type “carbanions” and active protons in a one-pot reaction, and at the same time achieves the first Grignard-type nucleophilic addition using olefinic alcohols as latent carbonyl groups, providing a higher yield of the corresponding secondary alcohol than the classical hydrazone addition to aldehydes does. A broad scope of unsaturated alcohols and hydrazones, including some complex structures, can be successfully employed in this reaction, which shows the versatility of this approach and its suitability as an alternative, efficient means for the generation of secondary and tertiary alcohols.
- Kan, Jian,Li, Chao-Jun,Li, Chen-Chen,Li, Jianbin,Lv, Leiyang,Qiu, Zihang
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supporting information
p. 4544 - 4549
(2020/02/04)
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- Photochemical Alkene Isomerization for the Synthesis of Polysubstituted Furans and Pyrroles under Neutral Conditions
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A photochemical approach to polysubstituted heterocycles using UV-induced alkene isomerization is described. The method allows for the synthesis of disubstituted furans and pyrroles under mild and neutral conditions and also provides access to a class of trisubstituted furans pertinent to natural-product synthesis. The method has broad functional-group tolerance and many richly decorated heterocycles have been prepared incorporating functional groups that are unstable under Br?nsted and Lewis acidic conditions.
- Walker, Johannes C. L.,Werrel, Simon,Donohoe, Timothy J.
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supporting information
p. 13114 - 13118
(2019/10/22)
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- One-Pot Conversion of Allylic Alcohols to α-Methyl Ketones via Iron-Catalyzed Isomerization-Methylation
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A one-pot iron-catalyzed conversion of allylic alcohols to α-methyl ketones has been developed. This isomerization-methylation strategy utilized a (cyclopentadienone)iron(0) carbonyl complex as precatalyst and methanol as the C1 source. A diverse range of allylic alcohols undergoes isomerization-methylation to form α-methyl ketones in good isolated yields (up to 84% isolated yield).
- Latham, Daniel E.,Polidano, Kurt,Williams, Jonathan M. J.,Morrill, Louis C.
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supporting information
p. 7914 - 7918
(2019/10/16)
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- Manganese-Catalyzed Ring-Opening Coupling Reactions of Cyclopropanols with Enones
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A manganese-catalyzed ring-opening coupling reaction of cyclopropanols with enones for the facile and efficient preparation of 1,6-diketones is described. A wide array of synthetically important 1,6-diketones bearing manifold functional groups are obtained with up to 93% yield. These reactions feature broad substrate scopes, environmentally benign conditions, inexpensive catalyst, and operational simplicity.
- Zhang, Yong-Hui,Zhang, Wen-Wei,Zhang, Ze-Yu,Zhao, Kai,Loh, Teck-Peng
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supporting information
p. 5101 - 5105
(2019/07/03)
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- A Ba/Pd Catalytic System Enables Dehydrative Cross-Coupling and Excellent E-Selective Wittig Reactions
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A Ba/Pd cooperative catalysis system was developed to enable the dehydrative cross-coupling of allylic alcohols with P-ylides to occur directly and promote a subsequent Wittig reaction in one pot. A variety of multisubstituted 1,4-dienes were isolated in good to excellent yields with broad P-ylides (stabilized by both ester and ketone carbonyl groups) and aldehyde (aliphatic and aromatic) substrates with excellent E selectivity.
- Xie, Peizhong,Fu, Weishan,Cai, Xinying,Sun, Zuolian,Wu, Ying,Li, Shuangshuang,Gao, Cuiqing,Yang, Xiaobo,Loh, Teck-Peng
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supporting information
p. 7055 - 7059
(2019/09/12)
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- Enhanced activity and modified substrate-favoritism of Burkholderia cepacia lipase by the treatment with a pyridinium alkyl-PEG sulfate ionic liquid
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Three types of pyridinium salts, i.e., 1-ethylpyridin-1-ium cetyl-PEG10 sulfate (PYET), 1-butylpyridin-1-ium cetyl-PEG10 sulfate (PYBU), and 1-(3-methoxypropyl)pyridin-1-ium cetyl-PEG10 sulfate (PYMP), have been prepared and evaluated for their activation property of Burkholderia cepacia lipase by comparison to the control IL-coated enzymes, 1-butyl-2,3-dimethylimidazolium cetyl-PEG10 sulfate-coated lipase PS (IL1-PS). Among the tested pyridinium salt-coated lipases, the PYET-coated lipase PS (PYET-PS) exhibited the best results; the transesterification of 1-(pyridin-2-yl)ethanol, 1-(pyridin-3-yl)ethanol, 1-(pyridin-4-yl)ethanol, or 4-phenylbut-3-en-2-ol proceeded faster than those of the IL1-PS-catalyzed reaction while maintaining an excellent enantioselectivity (E > 200). This improved efficiency was found to be dependent on the increased Kcat value.
- Kadotani, Shiho,Nokami, Toshiki,Itoh, Toshiyuki
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p. 441 - 447
(2019/01/04)
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- Enantioselective vinylation of aldehydes with the vinyl Grignard reagent catalyzed by magnesium complex of chiral BINOLs
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Enantioselective vinylation of aldehydes via direct catalytic asymmetric Grignard reaction of aldehdyes and the vinyl Grinard reagent is a long-standing challenge. This work demonstrated that the magnesium (S)-3,3′-dimethyl BINOLate enantioselectively catalyze the direct vinylation of aldehydes with the deactivated vinylmagnesium bromide by bis(2-[N,N′-dimethylamino]ethyl) ether (BDMAEE) in the addition of n-butylmagnesium chloride. The highest ee of 63% was achieved up to date.
- Wang, Pei,Ma, Guo-Rong,Yu, Sheng-Li,Da, Chao-Shan
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supporting information
p. 79 - 86
(2018/12/13)
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- NRF2 ACTIVATOR
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Provided are compounds of Formula I, or pharmaceutically acceptable salts thereof, and methods for their use and production.
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Page/Page column 175-176
(2018/07/29)
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- Rapid Access to Thiolactone Derivatives through Radical-Mediated Acyl Thiol-Ene and Acyl Thiol-Yne Cyclization
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A new synthetic approach to thiolactones that employs an efficient acyl thiol-ene (ATE) or acyl thiol-yne (ATY) cyclization to convert unsaturated thiocarboxylic acid derivatives into thiolactones under very mild conditions is described. The high overall yields, fast kinetics, high diastereoselectivity, excellent regiocontrol, and broad substrate scope of these reaction processes render this a very useful approach for diversity-oriented synthesis and drug discovery efforts. A detailed computational rationale is provided for the observed regiocontrol.
- McCourt, Ruairi O.,Dénès, Fabrice,Sanchez-Sanz, Goar,Scanlan, Eoin M.
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supporting information
p. 2948 - 2951
(2018/05/28)
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- Nickel-Catalyzed Direct Coupling of Allylic Alcohols with Organoboron Reagents
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The direct coupling of allylic alcohols with arylboronic acids or their derivatives catalyzed by Ni(cod)2 in the presence of a catalytic amount of base has been developed. A wide variety of allylic substrates or arylboronic acids turned out to be applicable to this catalytic system. The present method does not require the use of ligands for stabilizing the nickel catalyst in most cases or additional activators for activation of allylic alcohols.
- Wang, Gaonan,Gan, Yi,Liu, Yuanhong
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supporting information
p. 916 - 920
(2018/09/22)
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- Rhodium-catalyzed enantioselective decarboxylative alkynylation of allenes with arylpropiolic acids
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A rhodium-catalyzed chemo-, regio-, and enantioselective intermolecular decarboxylative alkynylation of terminal allenes with arylpropiolic acids is reported. Employing a Rh(I)/(R)-Tol-BINAP catalytic system, branched allylic 1,4-enynes were obtained under mild conditions. The overall utility of this protocol is exemplified by a broad functional group compatibility.
- Grugel, Christian P.,Breit, Bernhard
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supporting information
p. 1066 - 1069
(2018/02/23)
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- Stereoselective Dynamic Cyclization of Allylic Azides: Synthesis of Tetralins, Chromanes, and Tetrahydroquinolines
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This report describes the stereoselective synthesis of 3-azido-tetralins, -chromanes, and -tetrahydroquinolines via a tandem allylic azide rearrangement/Friedel-Crafts alkylation. Exposure of allylic azides with a pendant trichloroacetimidate to catalytic quantities of AgSbF6 proved optimal for this transformation. This cascade successfully differentiates the equilibrating azide isomers, providing products in excellent yield and selectivity (>25 examples, up to 94% yield and >25:1 dr). In many cases, the reactive isomer is only a trace fraction of the equilibrium mixture, keenly illustrating the dynamic nature of these systems. We demonstrate the utility of this process via a synthesis of hasubanan.
- Porter, Matthew R.,Shaker, Rami M.,Calcanas, Cristian,Topczewski, Joseph J.
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supporting information
p. 1211 - 1214
(2018/02/09)
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- Enantioselective addition of selenosulfonates to α,β-unsaturated ketones
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An organo-catalyzed enantioselective addition of selenosulfonates to α,β-unsaturated ketones was developed for the first time. With a chiral squaramide as an efficient catalyst, the desired α-selenylated ketones were obtained in a good yields with high enantioselectivity up to 89% ee, and good results could be obtained on a gram scale. The products could also be efficiently transformed into useful building blocks with a propenylic stereocenter; the strategy presented in this study may find further applications in organic synthesis.
- Luo, Shilong,Zhang, Nan,Wang, Zhen,Yan, Hailong
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supporting information
p. 2893 - 2901
(2018/05/03)
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- Rhodium-Catalyzed Regio- and Enantioselective Addition of N-Hydroxyphthalimide to Allenes: A Strategy to Synthesize Chiral Allylic Alcohols
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We achieved the first Rh-catalyzed regio- and enantioselective additions of N-hydroxyphthalimide to allenes. This transformation is accomplished via mild reaction conditions, leveraging on Josiphos SL-J003-2 as a chiral ligand to furnish branched O-allyl compounds in good yields with moderate to excellent enantioselectivities. The substrate scope is broad, and various functional groups are tolerated. The utility of this methodology is elaborated by transformation to allylic alcohols with different functional groups as well as to chiral O-allyl hydroxylamines.
- Liu, Zi,Breit, Bernhard
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supporting information
p. 300 - 303
(2018/01/17)
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- Regioselective Ni-Catalyzed Carboxylation of Allylic and Propargylic Alcohols with Carbon Dioxide
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An efficient Ni-catalyzed reductive carboxylation of allylic alcohols with CO2 has been successfully developed, providing linear β,γ-unsaturated carboxylic acids as the sole regioisomer with generally high E/Z stereoselectivity. In addition, the carboxylic acids can be generated from propargylic alcohols via hydrogenation to give allylic alcohol intermediates, followed by carboxylation. A preliminary mechanistic investigation suggests that the hydrogenation step is made possible by a Ni hydride intermediate produced by a hydrogen atom transfer from water.
- Chen, Yue-Gang,Shuai, Bin,Ma, Cong,Zhang, Xiu-Jie,Fang, Ping,Mei, Tian-Sheng
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supporting information
p. 2969 - 2972
(2017/06/07)
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- Switchable Site-Selective Catalytic Carboxylation of Allylic Alcohols with CO2
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A switchable site-selective catalytic carboxylation of allylic alcohols has been developed in which CO2 is used with dual roles, both facilitating C?OH cleavage and as a C1 source. This protocol is characterized by its mild reaction conditions, absence of stoichiometric amounts of organometallic reagents, broad scope, and exquisite regiodivergency which can be modulated by the type of ligand employed.
- van Gemmeren, Manuel,B?rjesson, Marino,Tortajada, Andreu,Sun, Shang-Zheng,Okura, Keisho,Martin, Ruben
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supporting information
p. 6558 - 6562
(2017/05/29)
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- A Re2O7catalyzed cycloetherification of monoallylic diols
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A Re2O7catalyzed cycloetherification of monoallylic diols is described. The reaction features short reaction time, mild reaction conditions and exclusive E selectivity. A wide range of monoallylic alcohols with alkyl or aryl substituents on olefin smoothly undergo ring closure to deliver corresponding oxa-heterocycles. The reaction is also operationally simple and not sensitive to air and moisture.
- Wan, Xiaolong,Hu, Jiadong,Xu, Dongyang,Shang, Yang,Zhen, Yanxia,Hu, Chenchen,Xiao, Fan,He, Yu-Peng,Lai, Yisheng,Xie, Weiqing
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supporting information
p. 1090 - 1093
(2017/03/02)
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- Efficient Pd-Catalyzed Regio- and Stereoselective Carboxylation of Allylic Alcohols with Formic Acid
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Formic acid is efficiently used as a C1 source to directly carboxylate allylic alcohols in the presence of a low loading of palladium catalyst and acetic anhydride as additive to afford β,γ-unsaturated carboxylic acids with excellent chemo-, regio-, and stereoselectivity. The reaction proceeds through a carbonylation process with in situ-generated carbon monoxide under mild conditions, avoiding the use of high-pressure gaseous CO. A bisphosphine ligand with a large bite angle (4,5-bis{diphenylphosphino}-9,9-dimethylxanthene, Xantphos) was found to be uniquely effective for this transformation. The regio- and stereoconvergence of this reaction is ascribed to the thermodynamically favored isomerization of the allylic electrophile in the presence of the palladium catalyst.
- Fu, Ming-Chen,Shang, Rui,Cheng, Wan-Min,Fu, Yao
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supporting information
p. 8818 - 8822
(2017/07/11)
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- N-Heterocyclic Olefin Catalyzed Silylation and Hydrosilylation Reactions of Hydroxyl and Carbonyl Compounds
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N-Heterocyclic olefins (NHOs), the alkylidene derivatives of N-heterocyclic carbenes (NHCs), have recently emerged as a new family of promising organocatalysts with strong nucleophilicity and Br?nsted basicity. The development of a novel method is shown using NHOs as efficient promoters for the direct dehydrogenative silylation of alcohols or hydrosilylation of carbonyl compounds. Preliminary results of the first NHO-promoted asymmetric synthesis are also discussed.
- Kaya, U?ur,Tran, Uyen P.N.,Enders, Dieter,Ho, Junming,Nguyen, Thanh V.
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supporting information
p. 1398 - 1401
(2017/03/23)
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- Recognition of extended linear and cyclised polyketide mimics by a type II acyl carrier protein
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Polyketides are secondary metabolites which display both valuable pharmaceutical and agrochemical properties. Biosynthesis is performed by polyketide synthases (PKSs), and the acyl carrier protein (ACP), a small acidic protein, that transports the growing
- Dong, Xu,Bailey, Christopher D.,Williams, Christopher,Crosby, John,Simpson, Thomas J.,Willis, Christine L.,Crump, Matthew P.
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p. 1779 - 1785
(2016/03/05)
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- Isothiourea-Catalysed Acylative Kinetic Resolution of Aryl–Alkenyl (sp2vs. sp2) Substituted Secondary Alcohols
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The non-enzymatic acylative kinetic resolution of challenging aryl–alkenyl (sp2vs. sp2) substituted secondary alcohols is described, with effective enantiodiscrimination achieved using the isothiourea organocatalyst HyperBTM (1 mol %) and isobutyric anhydride. The kinetic resolution of a wide range of aryl–alkenyl substituted alcohols has been evaluated, with either electron-rich or naphthyl aryl substituents in combination with an unsubstituted vinyl substituent providing the highest selectivity (S=2–1980). The use of this protocol for the gram-scale (2.5 g) kinetic resolution of a model aryl–vinyl (sp2vs. sp2) substituted secondary alcohol is demonstrated, giving access to >1 g of each of the product enantiomers both in 99:1 e.r.
- Musolino, Stefania F.,Ojo, O. Stephen,Westwood, Nicholas J.,Taylor, James E.,Smith, Andrew D.
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supporting information
p. 18916 - 18922
(2016/12/26)
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- Highly regioselective homoallyl alcohol protection through ring opening of p-methoxybenzylidene acetal
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A highly regioselective homoallylic alcohol protection was achieved in the reductive cleavage of anisylidene acetal with DIBAL-H during the selective protection of hydroxyl group in terminal unsaturated diols which was unlikely compare to the diols present adjacent to internal and cyclic double bond. Reductive cleavage of terminal olefenic diols protected as its acetals gave exclusively allyl alcohol product in good to excellent yield. Though the actual reason of such observation is not quite clear, the current reductive protocol can be applied as an efficient solution for indirect protection of less reactive hydroxy group in preference to that of more reactive allylic one as PMB-mono ether.
- Bharath, Yada,Maduri, Spandana,Mohapatra, Debendra K.
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supporting information
p. 5344 - 5347
(2016/11/11)
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- Radical Cyclisation of α-Halo Aluminium Acetals: A Mechanistic Study
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α-Bromo aluminium acetals are suitable substrates for Ueno-Stork-like radical cyclisations affording γ-lactols and acid-sensitive methylene-γ-lactols in high yields. The mechanistic study herein sets the scope and limitation of this reaction. The influence of the halide (or chalcogenide) atom X (X=Cl, Br, I, SPh, SePh) in the precursors α-haloesters, as well as influence of the solvent and temperature was studied. The structure of the aluminium acetal intermediates resulting from the reduction of the corresponding α-haloesters has been investigated by low-temperature 13C-INEPT diffusion-ordered NMR spectroscopy (DOSY) experiments and quantum calculations, providing new insights into the structures of these thermally labile intermediates. Oxygen-bridged dimeric structures with a planar Al2O2 ring are proposed for the least hindered aluminium acetals, while monomeric structures seem to prevail for the most hindered species. A comparison against the radical cyclisation of aluminium acetals derived from allyl and propargyl alcohols with the parent Ueno-Stork has been made at the BHandHLYP/6-311++G(d,p) level of theory, highlighting mechanistic similarities and differences.
- Bénéteau, Romain,Boussonnière, Anne,Rouaud, Jean-Christophe,Lebreton, Jacques,Graton, Jéro?me,Jacquemin, Denis,Sebban, Muriel,Oulyadi, Hassan,Hamdoun, Ghanem,Hancock, Amber N.,Schiesser, Carl H.,Dénès, Fabrice
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supporting information
p. 4809 - 4824
(2016/04/05)
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- Compound And Method
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A compound of formula (I): (I) wherein Y is, Z is OR10, NR11R11 SR11, S(0)R11 S02R11, R10 is H, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted heterocyclyl, CO—R11, or a protecting group, and R11 is optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted heterocyclyl, or alkoxyl; a process for making a compound of formula (I); and a process for making a prostaglandin or a prostaglandin analogue using a compound of formula (I). wherein Y is
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Paragraph 0440-0446
(2015/06/17)
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- Organoselenium-catalyzed, hydroxy-controlled regio- and stereoselective amination of terminal alkenes: Efficient synthesis of 3-amino allylic alcohols
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An efficient route to prepare 3-amino allylic alcohols in excellent regio- and stereoselectivity in the presence of bases by orangoselenium catalysis has been developed. In the absence of bases α,β-unsaturated aldehydes were formed in up to 97% yield. Control experiments reveal that the hydroxy group is crucial for the direct amination.
- Deng, Zhimin,Wei, Jialiang,Liao, Lihao,Huang, Haiyan,Zhao, Xiaodan
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supporting information
p. 1834 - 1837
(2015/04/27)
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- Ligand-controlled regiodivergent Ni-catalyzed reductive carboxylation of allyl esters with CO2
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A novel Ni-catalyzed regiodivergent reductive carboxylation of allyl esters with CO2 has been developed. This mild, user-friendly, and operationally simple method is characterized by an exquisite selectivity profile that is dictated by the ligand backbone.
- Moragas, Toni,Cornella, Josep,Martin, Ruben
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supporting information
p. 17702 - 17705
(2015/02/19)
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- Synthesis of Quinolines from Allylic Alcohols via Iridium-Catalyzed Tandem Isomerization/Cyclization Combined with Potassium Hydroxide
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A new tandem catalytic process has been established for the synthesis of quinolines. This process utilizes the [IrCp?Cl2]2/KOH catalyzed isomerization/cyclization of allylic alcohols with 2-aminobenzyl alcohol. Both the secondary and primary allylic alcohols were investigated in this catalytic system to afford different substituted quinoline derivatives in moderate to good yields. A mechanism study showed the reaction following a tandem process integrating isomerization of allylic alcohols and oxidative cyclization of 2-aminobenzyl alcohol.
- Chen, Shu-Jie,Lu, Guo-Ping,Cai, Chun
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p. 976 - 984
(2015/03/30)
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- Regioselective catalytic asymmetric C-alkylation of isoxazolinones by a base-free palladacycle-catalyzed direct 1,4-addition
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Isoxazolinones constitute a class of heterocycles utilized for the development of novel drug candidates. The cyclic oxime ester motif is also synthetically useful as it contains functional handles which have previously been used to provide access to an assortment of valuable compound classes not easily accessible by alternative approaches. However, asymmetric methods towards isoxazolinones are notoriously scarce. Herein we report the first catalytic asymmetric alkylations of isoxazolinones forming all-C-substituted quaternary stereocenters. The present studies were driven by the question of how to control the regioselectivity in the competition of different nucleophilic positions. The investigation of a direct 1,4-addition uncovered that a sterically demanding palladacycle catalyst directs the reactivity in the absence of a base nearly exclusively to the nucleophilic C atom, while at the same time it allows for high enantioselectivity and TONs up to 1900.
- Hellmuth, Tina,Frey, Wolfgang,Peters, Ren
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supporting information
p. 2788 - 2791
(2015/03/04)
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- Highly Regioselective Palladium-Catalyzed Carboxylation of Allylic Alcohols with CO2
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Various allylic alcohols were carboxylated in the presence of a catalytic amount of PdCl2 and PPh3 using ZnEt2 as a stoichiometric transmetalation agent under a CO2 atmosphere (1atm). This carboxylation proceeded in a highly regioselective manner to afford branched carboxylic acids predominantly. The β,γ-unsaturated carboxylic acid thus obtained was successfully converted into an optically active γ-butyrolactone, a known intermediate of (R)-baclofen.
- Mita, Tsuyoshi,Higuchi, Yuki,Sato, Yoshihiro
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supporting information
p. 16391 - 16394
(2015/11/09)
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- Titanocene(III) chloride mediated radical-induced opening of monosubstituted epoxy acetates for the synthesis of primary allylic alcohols
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A simple and efficient method for the synthesis of primary allylic alcohols from monosubstituted epoxy acetates has been developed using titanocene(III) chloride mediated epoxide ring opening via acetate elimination.
- Chakraborty,Mandal,Roy
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p. 893 - 901
(2015/08/18)
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- 1,4-Diazabicyclo[2.2.2]octane-Promoted Aminotrifluoromethylthiolation of α,β-Unsaturated Carbonyl Compounds: N-Trifluoromethylthio-4-nitrophthalimide Acts as Both the Nitrogen and SCF3 Sources
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A novel difunctionalization reaction is described. It uses N-trifluoromethylthio-4-nitrophthalimide as the reagent, which serves as both the nitrogen and SCF3 sources. In the presence of DABCO (1,4-diazabicyclo[2.2.2]octane), the nitrogen and SCF3 groups can be incorporated into α,β-unsaturated carbonyl compounds easily and give versatile β-amino ketones and esters in good yields. This difunctionalization reaction features mild reaction conditions, high atom-economy, and efficient access to α-SCF3 amino acids.
- Xiao, Qing,He, Qijie,Li, Juncheng,Wang, Jun
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supporting information
p. 6090 - 6093
(2016/01/09)
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- Congested C-C bonds by Pd-catalyzed enantioselective allyl-allyl cross-coupling, a mechanism-guided solution
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Under the influence of a chiral bidentate diphosphine ligand, the Pd-catalyzed asymmetric cross-coupling of allylboron reagents and allylic electrophiles establishes 1,5-dienes with adjacent stereocenters in high regio-and stereoselectivity. A mechanistic study of the coupling utilizing reaction calorimetry and density functional theory analysis suggests that the reaction operates through an inner-sphere 3,3′-reductive elimination pathway, which is both rate-defining and stereodefining. Coupled with optimized reaction conditions, this mechanistic detail is used to expand the scope of allyl-allyl couplings to allow the generation of 1,5-dienes with tertiary centers adjacent to quaternary centers as well as a unique set of cyclic structures.
- Ardolino, Michael J.,Morken, James P.
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supporting information
p. 7092 - 7100
(2014/06/09)
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- Regio- and chemoselective intermolecular hydroamination of allyl imines for the synthesis of 1,2-diamines
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The synthesis of 1,2-diamines via a Rh-catalyzed intermolecular hydroamination of N-allyl imines with cyclic amines is presented. Coordinating groups proximal to the olefin bind to the catalyst and promote the transformation. The reaction affords 1,2-diam
- Ickes, Andrew R.,Ensign, Seth C.,Gupta, Anil K.,Hull, Kami L.
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supporting information
p. 11256 - 11259
(2014/09/29)
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- Iridium-catalyzed C-3 allylation of indoles with allylic alcohols promoted by a bronsted acid
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A highly regioselective method has been developed for the allylation of indoles with an iridium catalyst. This regioselective procedure uses allylic alcohols directly as allylating agents in the presence of a catalytic amount of sulfuric acid. A wide rang
- Chen, Shu-Jie,Lu, Guo-Ping,Cai, Chun
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supporting information
p. 1717 - 1724
(2014/07/08)
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- Enantioselective synthesis of 3-substituted 1,2-oxazinanes via organocatalytic intramolecular aza-Michael addition
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A highly enantioselective intramolecular 6-exo-trig aza-Michael addition was developed to afford chiral 3-substituted 1,2-oxazinanes in high yields (up to 99% yield) and good enantioselectivities (up to 98/2 er). These reactions were enabled by a quinine-derived primary-tertiary diamine as a catalyst and pentafluoropropionic acid (PFP) as a co-catalyst.
- Cheng, Shuanghua,Yu, Shouyun
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supporting information
p. 8607 - 8610
(2014/12/10)
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- Enantioselective transformation of allyl carbonates into branched allyl carbamates by using amines and recycling CO2 under iridium catalysis
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Enantioselective transformation of allyl carbonates into branched allyl carbamates by using amines and recycling CO2 in the presence of an Ir complex and K3PO4 was accomplished. This provided branched allyl carbamates in fair to excellent yields with up to 98:2 regioselectivity and 93% ee. The role of CO2 in this transformation is discussed as well.
- Zheng, Sheng-Cai,Zhang, Min,Zhao, Xiao-Ming
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supporting information
p. 7216 - 7221
(2014/06/23)
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- COMPOUND AND METHOD
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A compound of formula (I): (I) wherein Y is, Z is OR10, NR11R11 SR11, S(0)R11 S02R11, R10 is H, optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted heterocyclyl, CO-R11, or a protecting group, and R11 is optionally substituted alkyl, optionally substituted cycloalkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted heterocyclyl, or alkoxyl; a process for making a compound of formula (I); and a process for making a prostaglandin or a prostaglandin analogue using a compound of formula (I).
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Page/Page column 89
(2014/01/08)
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