- Palladium-Catalyzed Synthesis of α-Methyl Ketones from Allylic Alcohols and Methanol
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One-pot synthesis of α-methyl ketones starting from 1,3-diaryl propenols or 1-aryl propenols and methanol as a C1 source is demonstrated. This one-pot isomerization-methylation is catalyzed by commercially available Pd(OAc)2 with H2O as the only by-product. Mechanistic studies and deuterium labelling experiments indicate the involvement of isomerization of allyl alcohol followed by methylation through a hydrogen-borrowing pathway in these isomerization-methylation reactions.
- Biswal, Priyabrata,Samser, Shaikh,Meher, Sushanta Kumar,Chandrasekhar, Vadapalli,Venkatasubbaiah, Krishnan
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supporting information
p. 413 - 419
(2021/11/01)
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- Lanthanide-Catalyzed Tandem Addition of Amines to Cyanoalkenes: Synthesis of Cyclic Amidines
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A tandem insertion of aliphatic nitriles and unactivated alkenes to the N-H bond of secondary aliphatic amines catalyzed by simple trialkyl rare-earth metal complexes was disclosed. This reaction provides a highly atom-economic and stereoselective way to a range of cyclic amidines under mild reaction conditions.
- Hou, Jinsong,Yang, Gaosheng,Chai, Zhuo
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supporting information
p. 453 - 463
(2022/01/04)
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- Iridium-Catalyzed Asymmetric Allylic Alkylation of Deconjugated Butyrolactams
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Compared with the ever-growing list of nonprochiral nucleophiles in Ir-catalyzed asymmetric allylic substitution reactions, prochiral nucleophiles are less studied. We present a new prochiral nucleophile, namely, deconjugated butyrolactam, for Ir-catalyze
- Mitra, Sankash,Mukherjee, Santanu
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supporting information
p. 3021 - 3026
(2021/05/04)
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- Synthesis of C5-allylindoles through an iridium-catalyzed asymmetric allylic substitution/oxidation reaction sequence of N-alkyl indolines
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Iridium/Br?nsted acid cooperative catalyzed asymmetric allylic substitution reactions at the C5 position of indolines have been reported for the first time. The highly efficient protocol allows rapid access to various C5-allylated products in good to high
- Lu, Jiamin,Xu, Ruigang,Zeng, Haixia,Zhong, Guofu,Wang, Meifang,Ni, Zhigang,Zeng, Xiaofei
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supporting information
p. 3426 - 3431
(2021/05/07)
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- Enantioselective Allylation of Alkenyl Boronates Promotes a 1,2-Metalate Rearrangement with 1,3-Diastereocontrol
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Alkenyl boronates add to Ir(π-allyl) intermediates with high enantioselectivity. A 1,2-metalate shift forms a second C-C bond and sets a 1,3-stereochemical relationship. The three-component coupling provides tertiary boronic esters that can undergo multiple additional functionalizations. An extension to trisubstituted olefins sets three contiguous stereocenters.
- Davis, Colton R.,Luvaga, Irungu K.,Ready, Joseph M.
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supporting information
p. 4921 - 4927
(2021/05/04)
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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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- Pd-Catalyzed Asymmetric Acyl-Carbamoylation of an Alkene to Construct an α-Quaternary Chiral Cycloketone
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Herein, we report the palladium-catalyzed asymmetric acyl-carbamoylation of an alkene by employing thioesters as the acyl electrophiles and t-BuNC as the carbamoyl reagent, affording an α-quaternary chiral cycloketone in synthetically useful yields with excellent enantioselectivity. The reaction proceeded via asymmetric 1,2-migratory insertions of acyl-Pd into alkenes and subsequent migratory insertion of isocyanides into C(sp3)-PdII. The product could be diversified to some valuable skeletons with retention of enantiopurity, demonstrating the synthetic utility of this protocol.
- Liu, Min,Wang, Xing,Guo, Ziqiong,Li, Hanyuan,Huang, Wei,Xu, Hui,Dai, Hui-Xiong
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supporting information
p. 6299 - 6304
(2021/08/30)
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- Nickel-Catalyzed Reductive Csp2-Csp3Cross Coupling Using Phosphonium Salts
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A nickel-catalyzed reductive cross coupling with phosphonium salts and allylic C(sp3)-O bond electrophiles, which granted direct construction of the C(sp2)-C(sp3) bond, is successfully developed. The protocol features broad substrate scope, high-functional-group tolerance, and heterocycle compatibility. Notably, the much more challenging reductive cross coupling with heterocyclic thiazolylphosphonium salts has also been accomplished for the first time.
- Liang, Hongze,Lu, Xinyao,Luo, Yunjie,Man, Xi,Mou, Zehuai,Wang, Huifei,Wang, Yuting,Yang, Mengwan
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supporting information
p. 8183 - 8188
(2021/11/13)
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- Allylic and Allenylic Dearomatization of Indoles Promoted by Graphene Oxide by Covalent Grafting Activation Mode
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The site-selective allylative and allenylative dearomatization of indoles with alcohols was performed under carbocatalytic regime in the presence of graphene oxide (GO, 10 wt percent loading) as the promoter. Metal-free conditions, absence of stoichiometric additive, environmentally friendly conditions (H2O/CH3CN, 55 °C, 6 h), broad substrate scope (33 examples, yield up to 92 percent) and excellent site- and stereoselectivity characterize the present methodology. Moreover, a covalent activation model exerted by GO functionalities was corroborated by spectroscopic, experimental and computational evidences. Recovering and regeneration of the GO catalyst through simple acidic treatment was also documented.
- Lombardi, Lorenzo,Bellini, Daniele,Bottoni, Andrea,Calvaresi, Matteo,Monari, Magda,Kovtun, Alessandro,Palermo, Vincenzo,Melucci, Manuela,Bandini, Marco
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supporting information
p. 10427 - 10432
(2020/07/24)
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- In Situ Ring-Closing Strategy for Direct Synthesis of N-Heterocyclic Carbene Nickel Complexes and Their Application in Coupling of Allylic Alcohols with Aryl Boronic Acids
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A in situ ring-closing strategy was developed for the synthesis of N-heterocyclic carbene nickel complexes. The process was carried out in air, and did not require solvent purification. The resulting nickel complexes were investigated as catalysts for the coupling of allylic alcohols with aryl boronic acids. A wide range of allylic substrates and aryl acids proved to be applicable to this catalytic system. Control experiments suggest that the Ni(0) may be the true active species in the coupling reactions. (Figure presented.).
- Wang, Yu-Bin,Liu, Bin-Yuan,Bu, Qingqing,Dai, Bin,Liu, Ning
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supporting information
p. 2930 - 2940
(2020/06/17)
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- Synthesis of 2-(3-Arylallylidene)-3-oxindoles via Dirhodium(II)-Catalyzed Reaction of 3-Diazoindolin-2-imines with 1-Aryl-Substituted Allylic Alcohols and Computational Insights
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A straightforward approach for the synthesis of 2-(3-arylallylidene)-3-oxindoles has been achieved by the dirhodium(II)-catalyzed reaction of 3-diazoindolin-2-imines with 1-aryl-substituted allylic alcohols. This protocol employs easily accessible feedsto
- Gao, Ke,Kou, Luyao,Fu, Rui,Bao, Xiaoguang
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supporting information
p. 1292 - 1297
(2020/02/11)
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- Highly Enantioselective Iridium-Catalyzed Coupling Reaction of Vinyl Azides and Racemic Allylic Carbonates
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The iridium-catalyzed enantioselective coupling reaction of vinyl azides and allylic electrophiles is presented and provides access to β-chiral carbonyl derivatives. Vinyl azides are used as acetamide enolate or acetonitrile carbanion surrogates, leading to γ,δ-unsaturated β-substituted amides as well as nitriles with excellent enantiomeric excess. These products are readily transformed into chiral N-containing building blocks and pharmaceuticals. A mechanism is proposed to rationalize the chemoselectivity of this coupling reaction.
- Han, Min,Yang, Min,Wu, Rui,Li, Yang,Jia, Tao,Gao, Yuanji,Ni, Hai-Liang,Hu, Ping,Wang, Bi-Qin,Cao, Peng
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supporting information
p. 13398 - 13405
(2020/09/02)
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- Size-Exclusion Borane-Catalyzed Domino 1,3-Allylic/Reductive Ireland–Claisen Rearrangements: Impact of the Electronic and Structural Parameters on the 1,3-Allylic Shift Aptitude
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The reductive Ireland–Claisen rearrangement through borane-mediated hydrosilylation is reported. The method employs a borane catalyst with a special structural design and affords access to synthetically relevant products with high diastereoselectivity. Depending on electronic and structural parameters, the reaction can be coupled with a 1,3-allylic shift, thus the valence isomer of the Ireland–Claisen product is formed.
- Fegyverneki, Dániel,Kolozsvári, Natália,Molnár, Dániel,Egyed, Orsolya,Holczbauer, Tamás,Soós, Tibor
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supporting information
p. 2179 - 2183
(2019/01/04)
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- Ruthenium-Catalyzed Redox Isomerizations inside Living Cells
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Tailored ruthenium(IV) complexes can catalyze the isomerization of allylic alcohols into saturated carbonyl derivatives under physiologically relevant conditions, and even inside living mammalian cells. The reaction, which involves ruthenium-hydride intermediates, is bioorthogonal and biocompatible, and can be used for the "in cellulo" generation of fluorescent and bioactive probes. Overall, our research reveals a novel metal-based tool for cellular intervention, and comes to further demonstrate the compatibility of organometallic mechanisms with the complex environment of cells.
- Vidal, Cristian,Tomás-Gamasa, María,Gutiérrez-González, Alejandro,Mascarenas, José L.
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supporting information
p. 5125 - 5129
(2019/03/29)
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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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- Synthesis of Allylsilanes via Nickel-Catalyzed Cross-Coupling of Silicon Nucleophiles with Allyl Alcohols
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NiCl2(PMe3)2-catalyzed reaction of allyl alcohols with silylzinc reagents, including PhMe2SiZnCl, Ph2MeSiZnCl, and Ph3SiZnCl, was performed, achieving allylsilanes in high yields. Aryl- and heteroaryl-substituted allyl alcohols, (E)-3-arylprop-2-en-1-ols, 1-aryl-prop-2-en-1-ols, and (E)-1-phenylpent-1-en-3-ol can be employed in the transformation. A range of functional groups as well as heteroaryl groups were tolerated. Reaction exhibited high regioselectivity and E/Z-selectivity when 1- or 3-aryl-substituted allyl alcohols were used as the substrates. Reaction of chiral allyl alcohol, (S,E)-1-phenylpent-1-en-3-ol, yielded a configuration-inversion product (R,E)-dimethyl(phenyl)(1-phenylpent-1-en-3-yl)silane.
- Yang, Bo,Wang, Zhong-Xia
-
supporting information
p. 7965 - 7969
(2019/10/19)
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- Rh-Catalyzed Regioselective Dialkylation of Cage B-H bonds in o-Carboranes: Oxidative Heck Reactions via an Enol Isomerization
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In the presence of a carboxylic acid directing group, Rh-catalyzed regioselective directed dialkylation of B(4,5)-H bonds in o-carboranes and oxidative coupling with allylic alcohols is reported. This strategy constructs a series of 4,5-dialkylated o-carboranes in good yields with excellent regioselectivity. A possible catalytic cycle is proposed that involves a tandem sequence of Rh-catalyzed cage B-H activation, alkene insertion, selective β-H elimination, enol isomerization, and decarboxylation.
- Wang, Qian,Tian, Song,Zhang, Chuyi,Li, Jiangwei,Wang, Zhixuan,Du, Yongmei,Zhou, Ling,Lu, Jian
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supporting information
p. 8018 - 8021
(2019/10/19)
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- Catalytic Asymmetric Intramolecular Bromolactonization of α,β-Unsaturated Ketones
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Enantioselective bromolactonization by using an amino-urea catalyst to generate the important bromo-containing 3,4-dihydroisocoumarins is described. Excellent yields and good enantioselectivities could be achieved for various 3,4-dihydroisocoumarin compou
- Gan, Min,He, Hailong,Jiang, Xiaojian,Liu, Shenghui,Yi, Peng
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supporting information
p. 1474 - 1478
(2019/07/15)
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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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- Structural Modification of Natural Product Ganomycin i Leading to Discovery of a α-Glucosidase and HMG-CoA Reductase Dual Inhibitor Improving Obesity and Metabolic Dysfunction in Vivo
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It is a great challenge to develop drugs for treatment of metabolic syndrome. With ganomycin I as a leading compound, 14 meroterpene derivatives were synthesized and screened for their α-glucosidase and HMG-CoA reductase inhibitory activities. As a result, a α-glucosidase and HMG-CoA reductase dual inhibitor ((R,E)-5-(4-(tert-butyl)phenyl)-3-(4,8-dimethylnona-3,7-dien-1-yl)furan-2(5H)-one, 7d) with improved chemical stability and long-term safety was obtained. Compound 7d showed multiple and strong in vivo efficacies in reducing weight gain, lowering HbAlc level, and improving insulin resistance and lipid dysfunction in both ob/ob and diet-induced obesity (DIO) mice models. Compound 7d was also found to reduce hepatic steatosis in ob/ob model. 16S rRNA gene sequencing, SCFA, and intestinal mucosal barrier function analysis indicated that gut microbiota plays a central and causative role in mediating the multiple efficacies of 7d. Our results demonstrate that 7d is a promising drug candidate for metabolic syndrome.
- Wang, Kai,Bao, Li,Zhou, Nan,Zhang, Jinjin,Liao, Mingfang,Zheng, Zhongyong,Wang, Yujing,Liu, Chang,Wang, Jun,Wang, Lifeng,Wang, Wenzhao,Liu, Shuangjiang,Liu, Hongwei
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p. 3609 - 3625
(2018/05/01)
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- 1,3-Dioxa-[3,3]-sigmatropic Oxo-Rearrangement of Substituted Allylic Carbamates: Scope and Mechanistic Studies
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An unexpected 1,3-dioxa-[3,3]-sigmatropic rearrangement during the treatment of aryl- and alkenyl-substituted allylic alcohols with activated isocyanates is reported. The reorganization of bonds is highly dependent on the electron density of the aromatic
- Agirre, Maddalen,Henrion, Sylvain,Rivilla, Ivan,Miranda, José I.,Cossío, Fernando P.,Carboni, Bertrand,Villalgordo, José M.,Carreaux, Fran?ois
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p. 14861 - 14881
(2019/01/04)
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- Graphene Oxide Promotes Site-Selective Allylic Alkylation of Thiophenes with Alcohols
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The graphene oxide (GO) assisted allylic alkylation of thiophenes with alcohols is presented. Mild reaction conditions and a low GO loading enabled the isolation of a range of densely functionalized thienyl and bithienyl compounds in moderate to high yields (up to 90%). The cooperative action of the Br?nsted acidity, epoxide moieties, and π-surface of the 2D-promoter is highlighted as crucial in the reaction course of the present Friedel-Crafts-type protocol.
- Favaretto, Laura,An, Juzeng,Sambo, Marco,De Nisi, Assunta,Bettini, Cristian,Melucci, Manuela,Kovtun, Alessandro,Liscio, Andrea,Palermo, Vincenzo,Bottoni, Andrea,Zerbetto, Francesco,Calvaresi, Matteo,Bandini, Marco
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supporting information
p. 3705 - 3709
(2018/06/26)
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- Ruthenium(II)-Catalyzed Regio- and Stereoselective C-H Allylation of Indoles with Allyl Alcohols
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A ruthenium-catalyzed C-H allylation of indoles with allyl alcohols via β-hydroxide elimination is reported. Without external oxidants and expensive additives, this reaction features mild reaction conditions, compatibility with various functional groups, and good to excellent regioselectivity and stereoselectivity.
- Wu, Xiaowei,Ji, Haitao
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supporting information
p. 2224 - 2227
(2018/04/30)
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- Anti-proliferative, apoptotic induction, and anti-migration effects of hemi-synthetic 1’S-1’-acetoxychavicol acetate analogs on MDA-MB-231 breast cancer cells
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Nine analogs of 1′S-1′-acetoxychavicol acetate (ACA) were hemi-synthesized and evaluated for their anticancer activities against seven human cancer cell lines. The aim of this study was to investigate the anti-proliferative, apoptotic, and anti-migration effects of these compounds and to explore the plausible underlying mechanisms of action. We found that ACA and all nine analogs were non toxic to human mammary epithelial cells (HMECs) used as normal control cells, and only ACA, 1′-acetoxyeugenol acetate (AEA), and 1′-acetoxy-3,5-dimethoxychavicol acetate (AMCA) inhibited the growth of MDA-MB-231 breast cancer cells with a half-maximal inhibitory concentration (IC50) value of 30.0 μM based on 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay results, and were selected for further investigation. DNA fragmentation assays showed that these three compounds markedly induced apoptosis of MDA-MB-231 cells. Western blot analysis revealed increased expression levels of cleaved PARP, p53, and Bax, while decreased expression levels of Bcl-2 and Bcl-xL were seen after treatment, indicating that apoptosis was induced via the mitochondrial pathway. Moreover, ACA, AEA, and AMCA effectively inhibited the migration of MDA-MB-231 cells. They also downregulated the expression levels of pFAK/FAK and pAkt/Akt via the integrin β1-mediated signaling pathway. Collectively, ACA and its hemi-synthetic analogs, AEA and AMCA are seen as potential anticancer agents following their abilities to suppress growth, induce apoptosis, and inhibit migration of breast cancer cells.
- Liew, Su Ki,Azmi, Mohamad Nurul,In, Lionel L. A.,Awang, Khalijah,Nagoor, Noor Hasima
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p. 2763 - 2776
(2017/10/11)
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- Tandem SN2′ nucleophilic substitution/oxidative radical cyclization of aryl substituted allylic alcohols with 1,3-dicarbonyl compounds
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A novel and efficient tandem SN2′ nucleophilic substitution/oxidative radical cyclization reaction of aryl substituted allylic alcohols with 1,3-dicarbonyl compounds has been developed by using Mn(OAc)3 as an oxidant, which enables t
- Zhang, Zhen,Li, Cheng,Wang, Shao-Hua,Zhang, Fu-Min,Han, Xue,Tu, Yong-Qiang,Zhang, Xiao-Ming
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p. 3239 - 3247
(2017/04/24)
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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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- Regio- and enantioselective synthesis of chiral pyrimidine acyclic nucleosides via rhodium-catalyzed asymmetric allylation of pyrimidines
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A direct route to branched N-allylpyrimidine analogues is herein reported via the highly regio- and enantioselective asymmetric allylation of pyrimidines with racemic allylic carbonates. With [Rh(COD)Cl]2/chiral diphosphine as the catalyst, a r
- Liang, Lei,Xie, Ming-Sheng,Qin, Tao,Zhu, Man,Qu, Gui-Rong,Guo, Ha-Ming
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supporting information
p. 5212 - 5215
(2017/11/06)
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- Rhodium-Catalyzed Asymmetric N?H Functionalization of Quinazolinones with Allenes and Allylic Carbonates: The First Enantioselective Formal Total Synthesis of (?)-Chaetominine
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An unprecedented asymmetric N?H functionalization of quinazolinones with allenes and allylic carbonates was successfully achieved by rhodium catalysis with the assistance of chiral bidentate diphosphine ligands. The high efficiency and practicality of this method was demonstrated by a low catalyst loading of 1 mol % as well as excellent chemo-, regio-, and enantioselectivities with broad functional group compatibility. Furthermore, this newly developed strategy was applied as key step in the first enantioselective formal total synthesis of (?)-chaetominine.
- Zhou, Yirong,Breit, Bernhard
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supporting information
p. 18156 - 18160
(2017/12/13)
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- Expanding the scope of the Babler–Dauben oxidation: 1,3-oxidative transposition of secondary allylic alcohols
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We report the catalytic chromium-mediated oxidation of secondary allylic alcohols to give α,β-unsaturated aldehydes with exclusive (E)-stereoselectivity. This facile procedure employs catalytic PCC (5?mol?%) and periodic acid (H5IO6) as a co-oxidant. This transformation occurs specifically with aromatic substituted allyl alcohols containing both electron withdrawing and electron donating substituents as well as a range of functional groups.
- Killoran, Patrick M.,Rossington, Steven B.,Wilkinson, James A.,Hadfield, John A.
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supporting information
p. 3954 - 3957
(2016/08/09)
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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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- Titanocene(III) chloride mediated radical induced addition-elimination route to the synthesis of racemic and optically active trisubstituted tetrahydrofurans: Formal synthesis of magnofargesin and 7’-epimagnofargesin
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Titanocene(III) Chloride mediated radical induced synthesis of 4-benzylidene substituted tetrahydrofuran, a typical lignan skeleton, has been accomplished in good yield through addition-elimination route in racemic as well as in optically active forms. The method has been applied to the synthesis of furano lignans, magnofargesin (1) and 7’-epimagnofargesin (2) in optically active forms.
- Chakraborty,Mandal,Roy
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p. 1067 - 1079
(2016/07/19)
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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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- F- Nucleophilic-Addition-Induced Allylic Alkylation
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Herein we present a novel strategy based on palladium-catalyzed allylic alkylation by taking advantage of the nucleophilic addition of external fluoride onto gem-difluoroalkenes as the initiation step. The merit of this protocol is highly appealing, as it enables a formal allylation of trifluoroethylarene derivatives through the in situ generation of β-trifluorocarbanions, which otherwise are deemed to be problematic in deprotonative allylation. Furthermore, this strategy distinguishes itself by high modularity, operational simplicity, and wide substrate scope with respect to allyl carbonates, giving rise to a broad array of homoallyltrifluoromethane derivatives, which otherwise would not be easily obtained using existing synthetic methods.
- Tian, Panpan,Wang, Cheng-Qiang,Cai, Sai-Hu,Song, Shengjin,Ye, Lu,Feng, Chao,Loh, Teck-Peng
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supporting information
p. 15869 - 15872
(2016/12/23)
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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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- Tandem Benzylic Oxidation/Dihydroxylation of α-Vinyl- and α-Alkenylbenzyl Alcohols
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A de novo tandem benzylic oxidative dihydroxylation of α-vinyl- and α-alkenylbenzyl alcohols has been developed to give α,β-dihydroxypropiophenones (=2,3-dihydroxy-1-phenylpropan-1-ones) and α,β-dihydroxyalkyl phenones. This method was shown to be substrate-selective and specific for the oxidation of benzylic alcohols.
- Fernandes, Rodney A.,Kattanguru, Pullaiah
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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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- Synthesis of highly substituted γ-butyrolactones by a gold-catalyzed cascade reaction of benzyl esters
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Easily accessible benzylic esters of 3-butynoic acids in a gold-catalyzed cyclization/rearrangement cascade reaction provided 3-propargyl γ-butyrolactones with the alkene and the carbonyl group not being conjugated. Crossover experiments showed that the formation of the new C-C bond is an intermolecular process. Initially propargylic-benzylic esters were used, but alkyl-substituted benzylic esters worked equally well. In the case of the propargylic- benzylic products, a simple treatment of the products with aluminum oxide initiated a twofold tautomerization to the allenyl-substituted g-butyrolactones with conjugation of the carbonyl group, the olefin, and the allene. The synthetic sequence can be conducted stepwise or as a one-pot cascade reaction with similar yields. Even in the presence of the gold catalyst the new allene remains intact.
- Jaimes, Maria Camila Blanco,Ahrens, Alexander,Pfl?sterer, Daniel,Rudolph, Matthias,Hashmi, A. Stephen K.
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supporting information
p. 427 - 433
(2015/02/18)
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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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- Asymmetric transfer hydrogenation of secondary allylic alcohols
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Racemic secondary allylic alcohols were transformed into optically active secondary alcohols by a combined Rucatalyzed isomerization/asymmetric transfer-hydrogenation reaction. The catalyst was generated in situ in isopropyl alcohol from di-μ-chlorobis[(p-cymene)chlororuthenium(II)], the chiral ligand (1S,2S)-N-(p-tolylsulfonyl)-1,2-diphenylethylenediamine, and K2CO3, and the products were afforded in yields up to 97% with up to 93% enantiomeric excess without the use of hydrogen gas. A Hammett study revealed that the reaction rate was enhanced with electronwithdrawing aryl substituents. The reaction supports the recent work published by Adolfsson et al. as new methodology for the synthesis of chiral compounds from allylic alcohols.
- Shoola, Christopher O.,DelMastro, Thomas,Wu, Ruoqiu,Sowa, John R.
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supporting information
p. 1670 - 1673
(2015/05/27)
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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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- Iridium-catalyzed enantioselective allylation of silyl enol ethers derived from ketones and α,β-unsaturated ketones
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The unified Ir-catalyzed enantioselective allylic substitution reactions of silyl enol ethers derived from ketones and α,β-unsaturated ketones with branched, racemic allylic alcohols are described. This transformation is catalyzed by the Carreira system and proceeds without fluoride, and with high ee and b:l ratio. The synthetic utility of this method was illustrated by the concise enantioselective total synthesis of marine natural products calyxolane A, B and by the assignment of the absolute configuration of calyxolane A.
- Liang, Xiao,Wei, Kun,Yang, Yu-Rong
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supporting information
p. 17471 - 17474
(2015/12/09)
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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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- DMF as carbon source: Rh-catalyzed α-methylation of ketones
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An unprecedented Rh-catalyzed direct methylation of ketones with N,N-dimethylformamide (DMF) is disclosed. The reaction shows a broad substrate scope, tolerating both aryl and alkyl ketones with various substituents. Mechanistic studies suggest that DMF delivers a methylene fragment followed by a hydride in the methylation process.
- Li, Yang,Xue, Dong,Lu, Wei,Wang, Chao,Liu, Zhao-Tie,Xiao, Jianliang
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supporting information
p. 66 - 69
(2014/01/23)
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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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- N-Heterocyclic carbene-catalyzed double acylation of enones with benzils
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Thiazolium carbene-catalyzed reaction of aromatic 1,2-diketones with enones in aprotic solvents gave double acylation products in good yields, whereas hydroacylation products formed by Stetter reaction were not detected at all. These results suggested the generation of aroyloxyenamine species from the 1,2-diketones instead of hydroxyenamines (Breslow intermediates). This journal is
- Takaki, Ken,Ohno, Akira,Hino, Makoto,Shitaoka, Takashi,Komeyama, Kimihiro,Yoshida, Hiroto
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supporting information
p. 12285 - 12288
(2014/12/11)
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- Ruthenium-catalyzed tandem-isomerization/asymmetric transfer hydrogenation of allylic alcohols
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A one-pot procedure for the direct conversion of racemic allylic alcohols to enantiomerically enriched saturated alcohols is presented. The tandem-isomerization/ asymmetric transfer hydrogenation process is efficiently catalyzed by [{Ru(p-cymene)Cl2}2] in combination with the a-amino acid hydroxyamide ligand 1, and performed under mild conditions in a mixture of ethanol and THF. The saturated alcohol products are isolated in good to excellent chemical yields and in enantiomeric excess up to 93%.
- Slagbrand, Tove,Lundberg, Helena,Adolfsson, Hans
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supporting information
p. 16102 - 16106
(2015/01/09)
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- Catalytic enantioselective allyl-allyl cross-coupling with a borylated allylboronate
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Catalytic enantioselective allyl-allyl cross-coupling of a borylated allylboronate reagent gives versatile borylated chiral 1,5-hexadienes. These compounds may be manipulated in a number of useful ways to give functionalized chiral building blocks for asymmetric synthesis.
- Le, Hai,Kyne, Robert E.,Brozek, Laura A.,Morken, James P.
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p. 1432 - 1435
(2013/07/05)
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