- An efficient Pd@Pro-GO heterogeneous catalyst for the α, β-dehydrogenation of saturated aldehyde and ketones
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An Efficient Pd@Pro-GO heterogeneous catalyst was developed that can promote the α, β-dehydrogenation of saturated aldehyde and ketones in the yield of 73% ? 92% at mild conditions without extra oxidants and additives. Pd@Pro-GO heterogeneous catalyst was synthesized via two steps: firstly, the Pro-GO was obtained by the esterification reaction between graphene oxide (GO) and N-(tert-Butoxycarbonyl)-L-proline (Boc-Pro-OH), followed by removing the protection group tert-Butoxycarbonyl (Boc), which endowed the proline-functionalized GO with both the lewis acid site (COOH) and the bronsted base site (NH), besides, the pyrrolidine of proline also can form imine with aldehydes to activate these substrates; Second, palladium was dispersed on the proline-functionalized GO (Pro-GO) to obtained heterogeneous catalyst Pd@Pro-GO. Mechanistic studies have shown that the Pd@Pro-GO-catalyzed α,β-dehydrogenation of saturated aldehyde and ketones was realized by an improved heterogeneously catalyzed Saegusa oxidation reaction. Based on the obove characteristics, the Pd@Pro-GO will be widely used in the transition metal catalytic field.
- Pan, Gao-Fei,Wang, Zhe,Chang, Yi-Yuan,Hao, Yue,Wang, Yi-Chen,Xing, Rui-Guang
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supporting information
(2021/12/30)
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- Tandem oxidation-dehydrogenation of (hetero)arylated primary alcohols via perruthenate catalysis
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Tandem oxidative-dehydrogenation of primary alcohols to give a,b-unsaturated aldehydes in one pot are rare transformations in organic synthesis, with only two methods currently available. Reported herein is a novel method using the bench-stable salt methyltriphenylphosphonium perruthenate (MTP3), and a new co-oxidant NEMO&middoPF6 (NEMO = N-ethyl-N-hydroxymorpholinium) which provides unsaturated aldehydes in low to moderate yields. The Ley-Griffith oxidation of (hetero)arylated primary alcohols with N-oxide co-oxidants NMO (NMO = N-methylmorpholine N-oxide)/NEMO, is expanded by addition of the N-oxide salt NEMO&middoPF6 to convert the intermediate saturated aldehyde into its unsaturated counterpart. The discovery, method development, reaction scope, and associated challenges of this method are highlighted. The conceptual value of late-stage dehydrogenation in natural product synthesis is demonstrated via the synthesis of a polyene scaffold related to auxarconjugatin B.
- Bettencourt, Christian J.,Chow, Sharon,Moore, Peter W.,Read, Christopher D.G.,Jiao, Yanxiao,Bakker, Jan Peter,Zhao, Sheng,Bernhardt, Paul V.,Williams, Craig M.
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p. 652 - 659
(2021/09/08)
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- Enantiodivergent One-Pot Synthesis of Axially Chiral Biaryls Using Organocatalyst-Mediated Enantioselective Domino Reaction and Central-to-Axial Chirality Conversion
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Enantiodivergent one-pot synthesis of biaryls was developed using a catalytic amount of a single chiral source. A domino organocatalyst-mediated enantioselective Michael reaction and aldol condensation provided centrally chiral dihydronaphthalenes with excellent enantioselectivity, from which an enantiodivergent chirality conversion from central-to-axial chirality was achieved. Both enantiomers of biaryls were obtained with excellent enantioselectivity. All transformations can be conducted in a single reaction vessel. A plausible reaction mechanism for the enantiodivergence is proposed.
- Hayashi, Yujiro,Koshino, Seitaro,Kwon, Eunsang,Monde, Kenji,Taniguchi, Tohru
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p. 15786 - 15794
(2021/10/14)
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- Method for preparing olefine aldehyde by catalyzing terminal alkyne or terminal conjugated eneyne and diphosphine ligand used in method
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The invention discloses a method for preparing olefine aldehyde by catalyzing terminal alkyne or terminal conjugated eneyne and a diphosphine ligand used in the method. According to the invention, indole-substituted phosphoramidite diphosphine ligand which is stable in air and insensitive to light is synthesized by utilizing a continuous one-pot method, and the indole-substituted phosphoramidite diphosphine ligand and a rhodium catalyst are used for jointly catalyzing to successfully achieve a hydroformylation reaction of aromatic terminal alkyne and terminal conjugated eneyne under the condition of synthesis gas for the first time, so that an olefine aldehyde structure compound can be rapidly and massively prepared, and particularly, a polyolefine aldehyde structure compound which is more difficult to synthesize in the prior art can be easily prepared and synthesized, and a novel method is provided for synthesis and modification of drug molecules, intermediates and chemical products.
- -
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Paragraph 0149-0154
(2021/05/29)
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- Selective Rhodium-Catalyzed Hydroformylation of Terminal Arylalkynes and Conjugated Enynes to (Poly)enals Enabled by a π-Acceptor Biphosphoramidite Ligand
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The hydroformylation of terminal arylalkynes and enynes offers a straightforward synthetic route to the valuable (poly)enals. However, the hydroformylation of terminal alkynes has remained a long-standing challenge. Herein, an efficient and selective Rh-catalyzed hydroformylation of terminal arylalkynes and conjugated enynes has been achieved by using a new stable biphosphoramidite ligand with strong π-acceptor capacity, which affords various important E-(poly)enals in good yields with excellent chemo- and regioselectivity at low temperatures and low syngas pressures.
- Zhao, Jiangui,Zheng, Xueli,Tao, Shaokun,Zhu, Yuxin,Yi, Jiwei,Tang, Songbai,Li, Ruixiang,Chen, Hua,Fu, Haiyan,Yuan, Maolin
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supporting information
p. 6067 - 6072
(2021/08/16)
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- Biocatalytic Asymmetric Cyclopropanations via Enzyme-Bound Iminium Ion Intermediates
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Cyclopropane rings are an important structural motif frequently found in many natural products and pharmaceuticals. Commonly, biocatalytic methodologies for the asymmetric synthesis of cyclopropanes rely on repurposed or artificial heme enzymes. Here, we engineered an unusual cofactor-independent cyclopropanation enzyme based on a promiscuous tautomerase for the enantioselective synthesis of various cyclopropanes via the nucleophilic addition of diethyl 2-chloromalonate to α,β-unsaturated aldehydes. The engineered enzyme promotes formation of the two new carbon-carbon bonds with excellent stereocontrol over both stereocenters, affording the desired cyclopropanes with high diastereo- and enantiopurity (d.r. up to 25:1; e.r. up to 99:1). Our results highlight the usefulness of promiscuous enzymes for expanding the biocatalytic repertoire for non-natural reactions.
- Kunzendorf, Andreas,Poelarends, Gerrit J.,Saifuddin, Mohammad,Saravanan, Thangavelu,Xu, Guangcai
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supporting information
p. 24059 - 24063
(2021/10/07)
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- Scalable Aerobic Oxidation of Alcohols Using Catalytic DDQ/HNO3
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A selective, practical, and scalable aerobic oxidation of alcohols is described that uses catalytic amounts of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and HNO3, with molecular oxygen serving as the terminal oxidant. The method was successfully applied to the oxidation of a wide range of benzylic, propargylic, and allylic alcohols, including two natural products, namely, carveol and podophyllotoxin. The conditions are also applicable to the selective oxidative deprotection of p-methoxybenzyl ethers.
- Arseniyadis, Stellios,Clavier, Louis,Copin, Chloé,Fournier, Jean,Giffard, Jean-Fran?ois,Jean, Alexandre,Katsina, Tania,Macedo Portela Da Silva, Nayane,Tamion, Rodolphe
-
supporting information
p. 856 - 860
(2020/07/14)
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- Enantiocomplementary Epoxidation Reactions Catalyzed by an Engineered Cofactor-Independent Non-natural Peroxygenase
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Peroxygenases are heme-dependent enzymes that use peroxide-borne oxygen to catalyze a wide range of oxyfunctionalization reactions. Herein, we report the engineering of an unusual cofactor-independent peroxygenase based on a promiscuous tautomerase that accepts different hydroperoxides (t-BuOOH and H2O2) to accomplish enantiocomplementary epoxidations of various α,β-unsaturated aldehydes (citral and substituted cinnamaldehydes), providing access to both enantiomers of the corresponding α,β-epoxy-aldehydes. High conversions (up to 98 %), high enantioselectivity (up to 98 % ee), and good product yields (50–80 %) were achieved. The reactions likely proceed via a reactive enzyme-bound iminium ion intermediate, allowing tweaking of the enzyme's activity and selectivity by protein engineering. Our results underscore the potential of catalytic promiscuity for the engineering of new cofactor-independent oxidative enzymes.
- Crotti, Michele,Kataja, Kim M.,Poelarends, Gerrit J.,Saravanan, Thangavelu,Xu, Guangcai
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supporting information
p. 10374 - 10378
(2020/04/23)
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- Highly Enantioselective Synthesis of Functionalized Glutarimide Using Oxidative N-Heterocyclic Carbene Catalysis: A Formal Synthesis of (?)-Paroxetine
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A simple yet highly effective approach toward enantioselective synthesis of trans-3,4-disubstituted glutarimides from readily available starting materials is developed using oxidative N-heterocyclic carbene catalysis. The catalytic reaction involves a formal [3 + 3] annulation between enals and substituted malonamides enabling the production of glutarimide derivatives in a single chemical operation via concomitant formation of C-C and C-N bonds. The reaction offers easy access to a broad range of functionalized glutarimides with excellent enantioselectivity and good yield. Synthetic application of the method is demonstrated via formal synthesis of (?)-paroxetine and other bioactive molecules.
- Porey, Arka,Santra, Surojit,Guin, Joyram
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p. 5313 - 5327
(2019/04/16)
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- Enantioselective Organocatalytic Enamine C?H Oxidation/Diels- Alder Reaction
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α,β-unsaturated aldehydes have been traditionally used in LUMO lowering asymmetric aminocatalysis (iminium catalysis), while the use of saturated aldehydes as substrates in this type of catalysis has been elusive, until recently. Herein, we demonstrate that organic, single-electron oxidants in the presence of diarylprolinol silylether type catalysts serve as effective tools for the transformation of electron rich enamines to iminium ions which partake in a subsequent Diels-Alder reaction. This enantioselective one-pot transformation represents the first example of saturated aldehydes being used in domino Diels-Alder reaction processes and demonstrates the power of this protocol for construction of stereo-defined chiral compounds and building blocks. (Figure presented.).
- D?ambaski, Zdravko,Tzaras, Dimitrios-Ioannis,Lee, Sunggi,Kokotos, Christoforos G.,Bondzic, Bojan P.
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supporting information
p. 1792 - 1797
(2019/02/25)
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- Phosphorous acid promoted isomerization of propargyl alcohols to α,β-unsaturated carbonyl compounds
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A metal-free and two-phase protocol for the Meyer-Schuster isomerization of propargyl alcohols to the corresponding α,β-unsaturated carbonyl compounds has been achieved in the presence of stoichiometric phosphorous acid aqueous solution, which produces the desired products in high yields with excellent stereoselectivity. Compared with the traditional methods, the procedure features broad scope of the substrates, mild conditions, and easy separation, providing an appealing alternative to the Meyer-Schuster reaction.
- Gan, Xiaotang,Fu, Zuqi,Liu,Yan, Yani,Chen, Chao,Zhou, Yongbo,Dong, Jianyu
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- Palladium-Catalyzed Formylation of Alkenylzinc Reagents with S-(4-Nitrophenyl) Thioformate
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We report the synthesis of enal compounds by palladium-catalyzed formylation of alkenylzinc reagents with S-(4-nitrophenyl) thioformate. Various functional groups were tolerated in the present reaction. 1H NMR experiments revealed that the products had a non-protected formyl group, which can be utilized for further C–C bond formation reactions. We successfully achieved the one-pot synthesis of a 1,5-diene-3-ol compound via sequential formylation and allylation.
- Haraguchi, Ryosuke,Tanazawa, Sho-Go,Tokunaga, Naoya,Fukuzawa, Shin-Ichi
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p. 1761 - 1764
(2018/04/27)
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- Carbocation catalysed ring closing aldehyde-olefin metathesis
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A highly efficient aldehyde-olefin metathesis catalysed by the carbocation, 4-phenylphenyl-diphenylmethylium ion, has been developed. This protocol is characterized by high yields, low catalyst loading (down to 2 mol%), good functional group compatibility and mild reaction conditions.
- Ni, Shengjun,Franzén, Johan
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p. 12982 - 12985
(2018/11/23)
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- Synthesis of Naphthoxazoles by Photocyclization of 4-/5-(Phenylethenyl)oxazoles
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Promising test results on the biological activity of our previously described naphtho[1,2-d]oxazoles and heterobenz[1,2-d]oxazoles, obtained by the photochemical cyclization of 5-phenylethenyl- and 5-heteroarylethenyloxazoles, prompted us to continue with the photochemical synthesis of substituted naphtho[1,2-d]oxazoles, and to extend the photochemical cyclization to the synthesis of naphtho/heterobenz[2,1-d]oxazoles from 4-(aryl/heteroarylethenyl)oxazoles. The required p- and o-phenyl-substituted 5-arylethenyloxazoles were prepared from the corresponding α,β-unsaturated aldehydes and the TosMIC reagent (tosylmethyl isocyanide) by the Van Leusen reaction. The substituted 4-(aryl/heteroarylethenyl)oxazoles were prepared by the Wittig reaction starting from various phosphonium salts and 2-H/methyl-4-oxazolecarbaldehydes.
- ?agud, Ivana,?indler-Kulyk, Marija,?kori?, Irena,Kelava, Vanja,Marini?, ?eljko
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p. 3326 - 3335
(2018/07/13)
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- Palladium-catalyzed hydroformylation of terminal arylacetylenes with glyoxylic acid
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A simple, practical and governable palladium-catalyzed hydroformylation of terminal arylacetylenes has been disclosed. The reaction proceeds under syngas-free conditions, using readily available glyoxylic acid as the formyl source, under mild conditions, giving rise to a broad range of α,β-unsaturated aldehydes.
- Liu, Yang,Cai, Liangzhen,Xu, Sheng,Pu, Weiwen,Tao, Xiaochun
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supporting information
p. 2166 - 2168
(2018/03/06)
-
- 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
-
supporting information
p. 233 - 237
(2018/03/21)
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- Palladium-Catalyzed Regioselective Aerobic Allylic C?H Oxygenation: Direct Synthesis of α,β-Unsaturated Aldehydes and Allylic Alcohols
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A protocol for the synthesis of α,β-unsaturated aldehydes and allylic alcohols from simple allylic hydrocarbons with water via palladium-catalyzed functionalization of allylic C?H bonds was described. Molecular oxygen is utilized as the sole oxidant in this oxygenation of terminal alkenes. This protocol features good functional group compatibility, broad substrate scope, and high atom- and step-economy. Moreover, the synthetic utility of this method can be highlighted by its application to the synthesis of ibuprofen, which is a highly potent analgesic. (Figure presented.).
- Li, Chunsheng,Chen, Huoji,Li, Jianxiao,Li, Meng,Liao, Jianhua,Wu, Wanqing,Jiang, Huanfeng
-
supporting information
p. 1600 - 1604
(2018/03/05)
-
- Barbiturate and thiobarbiturate compounds for use in cancer therapy
-
Provided are methods and compositions for use in therapy, and in particular for treating cancer, preferably drug-resistant cancer, and/or radiation resistant cancer. The compounds may be used for reducing tumor size in a mammalian subject and for inducing apoptosis in a tumor cell. The methods are effective on tumor cells that are resistant to drugs such as temozolomide, doxorubicin, and geldanamycin, as well as non-resistant tumor cells. Further provided are barbiturate and thiobarbiturates diene compounds for use in treating cancer, and uses, methods and compositions relating to these compounds.
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- Silylative Reductive Amination of α,β-Unsaturated Aldehydes: A Convenient Synthetic Route to β-Silylated Secondary Amines
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Described here is a reductive amination/hydrosilylation cascade of α,β-unsaturated aldehydes mediated by a Lewis acidic borane catalyst. The present reaction system provides an one-pot synthetic route towards β-silylated secondary amines that have not been accessible by other previous catalysis. Comparative 1H NMR studies on the silylative reduction of enimines revealed that steric bulkiness of primary amine reactants strongly affects both catalytic efficiency and regioselectivity. This strategy was applicable to a broad range of substrates and amenable to one-pot gram-scale synthesis. Moreover, a diastereoselective introduction of the β-silyl group was also found to be feasible (d.r. up to 71:29).
- Kim, Eunae,Park, Sehoon,Chang, Sukbok
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supporting information
p. 5765 - 5769
(2018/03/28)
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- Synthesis of Highly Substituted Arenes via Cyclohexadiene-Alkene C-H Cross Coupling and Aromatization
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The development of a cross-coupling method for the regioselective β-alkenylation of 2,5-cyclohexadiene carboxylic acid derivatives to form ortho-alkenylarenes through in situ decarboxylation and aromatization is described. The carboxylic acid functionality is used as a traceless directing group for efficient and mild β-alkenylation. The modular sequence comprises a reductive Birch α-alkylation, ionic ?-alkylation followed by a Pd-catalyzed decarboxylative β-alkenylation with subsequent aromatization resulting in an overall three-fold ipso-para-ortho functionalization of readily accessed benzoic acid derivatives. Efficient synthesis of various alkyl-alkenylarenes under mild conditions in moderate to excellent yields is presented.
- Bhunia, Anup,Studer, Armido
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p. 1213 - 1217
(2018/02/14)
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- Hendrickson reagent induced rearrangement of aryl propargyl alcohols to α,β-unsaturated aldehydes
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The Hendrickson reagent (triphenylphosphonium anhydride trifluoromethanesulfonate), prepared from the reaction of triphenylphosphine oxide (Ph3PO) and triflic anhydride (Tf2O) (2:1 stoichiometry), promotes dehydrations and various coupling reactions. The reagent has been used to transform oximes to nitriles and to prepare esters, amides and many other functional groups through the intermediacy of an alkoxyphosphonium salt. The reagent proved useful in heterocycle synthesis of thiazolines, imidazolines, quinoline precursors, isoquinolines, β-carbolines, phenanthridines, 11H-indolo[3,2-c]quinolines, quinoline-lactones, furoquinolinones, and indolizino[1,2-b]quinolin-9(11H)-ones. Moreover, the reagent has been key to the successful total synthesis of several natural products. Aryl propargyl alcohols with a terminal α-acetylenic group undergo rapid conversion to the corresponding α,β-unsaturated aldehydes at room temperature in dichloromethane in the presence of one equivalent of triphenylphosphonium anhydride trifluoromethanesulfonate. The reaction involved adding freshly distilled Tf2O (1.0 mmol) to a solution of Ph3PO (2.0 mmol) in CH2Cl2 (10 mL) at 0oC under N2 atmosphere. After stirring for 10 min, the propargyl alcohol (1.0 mmol) was added as a CH2Cl2 solution (2 mL), followed by the addition of water and Et3N (2.0 mmol) and further stirring at room temperature for 1h. Subsequent workup with 5% NaHCO3 (20 mL) and purification afforded α,β-unsaturated aldehydes. Eighteen aryl propargyl alcohol substrates with a terminal α-acetylenic group were transformed in good to excellent yields (71-85%) to enals. The methodology proved successful with secondary and tertiary alcohols with stereoselectivity favouring exclusively the E isomer. All the synthesized compounds are known and were characterized (1H,13C, and M.P) and compared to literature values. The method offers several advantages such as exclusive stereoselectivity, short reaction time, good yield, mild reaction conditions, and simple operational procedure.
- Moussa, Ziad,Aljuhani, Ateyatallah
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p. 845 - 853
(2018/11/06)
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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
-
supporting information
p. 8145 - 8159
(2017/10/18)
-
- Enantioselective Intermolecular Addition of Aliphatic Amines to Acyclic Dienes with a Pd-PHOX Catalyst
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We report a method for the catalytic, enantioselective intermolecular addition of aliphatic amines to acyclic 1,3-dienes. In most cases, reactions proceed efficiently at or below room temperature in the presence of 5 mol % of a Pd catalyst bearing a PHOX ligand, generating allylic amines in up to 97:3 er. The presence of an electron-deficient phosphine within the ligand not only leads to a more active catalyst but also is critical for achieving high site selectivity in the transformation.
- Adamson, Nathan J.,Hull, Ethan,Malcolmson, Steven J.
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p. 7180 - 7183
(2017/06/05)
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- Cascade reaction of propargylic alcohols with hydroxylamine hydrochloride: facile synthesis of α,β-unsaturated oximes and nitriles
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We have developed an easy and practical method for the synthesis of α,β-unsaturated oximes and nitriles from readily available propargylic alcohols with hydroxylamine hydrochloride (NH2OH·HCl) under metal-free conditions. By using or not using p-toluenesulfonyl chloride (p-TsCl) as the dehydrating promoter, the desired nitriles or oximes could be obtained, respectively via a three-step one-pot or two-step one-pot process in moderate to excellent yields with good functional group compatibility.
- Zhang, Qi,Zhang, Linjing,Tang, Chaojun,Luo, Huan,Cai, Xuediao,Chai, Yonghai
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p. 6935 - 6942
(2016/10/14)
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- A Ruthenium/Phosphoramidite-Catalyzed Asymmetric Interrupted Metallo-ene Reaction
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Allylic chlorides prepared from commercially available trans-1,4-dichloro-2-butene were converted to trans-disubstituted 5- and 6-membered ring systems with perfect diastereoselectivity and high enantioselectivity under chiral ruthenium catalysis. These products contain stereodefined secondary and tertiary alcohols that originate from the trapping of an alkylruthenium intermediate with adventitious water. Key to the success of this transformation was the development of a new BINOL-based phosphoramidite ligand containing bulky substitution at its 3- and 3′-positions. As a demonstration of product utility, diastereoselective Friedel-Crafts reactions were performed on the chiral benzylic alcohols in high yield and stereoselectivity.
- Trost, Barry M.,Ryan, Michael C.
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supporting information
p. 2981 - 2984
(2016/03/19)
-
- Wittig Reactions of Trialkylphosphine-derived Ylides: New Directions and Applications in Organic Synthesis
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The development of semi-stabilized, stabilized, and functionalized ylides derived from short-chain trialkylphosphines in the Wittig-type olefination reactions toward the synthesis of alkenes, including stilbenes, styrenes, and 1,3-dienes, as well as reagents for homologation reactions, are described. The methods allow easy access to alkenes with high (E)-stereoselectivity in good yield. These reactions are conducted with weak bases in aqueous media, which allows easy separation of water-soluble phosphine oxides. The development of a mild organocatalytic process for the Wittig reaction and extension toward the preparation of reporter stilbenes under biological conditions are also described. Applications toward the preparation of biologically active natural products and derivatives are discussed.
- McNulty, James,McLeod, David,Das, Priyabrata,Zepeda-Velázquez, Carlos
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p. 619 - 632
(2016/01/15)
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- Highly regio- And enantioselective synthesis of g,d-unsaturated amido esters by catalytic hydrogenation of conjugated enamides
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An efficient and highly regio- and enantioselective catalytic asymmetric hydrogenation of a,γ-dienamido esters to g,d-unsaturated amido esters has been achieved using Rh/ TangPhos as the catalyst. A series of γ,δ-unsaturated amido acids were furnished in excellent yields with up to 99%ee. This effective methodology was applied in the asymmetric synthesis of key intermediate of Ramipril, an ACE inhibitor.
- Min, Gao,Jing-jing, Meng,Hui, Lv,Xumu, Zhang
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supporting information
p. 1885 - 1887
(2015/02/19)
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- NEUROACTIVE COMPOUNDS AND METHODS OF USING THE SAME
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The invention described herein relates generally to neuroactive compounds and compositions for the treatment psychotic disorders, methods for treating psychosis using these neuroactive compounds, and methods for screening for novel neuroactive compounds. Certain aspects are directed to a family of compounds called "finazines." Certain aspects are directed to in vivo screening methods using high-throughput behavioral assays in zebrafish.
- -
-
Paragraph 00195; 00200
(2016/05/11)
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- Development of a robust reagent for the two-carbon homologation of aldehydes to (E)-α,β-unsaturated aldehydes in water
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Synthesis of a new pinacolacetal-phosphonium salt and its reaction with aldehydes to give homologated acetals and two-carbon homologated unsaturated aldehydes is presented. The chemistry takes place in water under mild conditions and the sequence can be performed in one-flask operation.
- Mcnulty, James,Zepeda-Velazquez, Carlos,McLeod, David
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supporting information
p. 3146 - 3149
(2013/11/06)
-
- Titanium-catalyzed intermolecular hydroaminoalkylation of conjugated dienes
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Ti me kangaroo down: Conjugated dienes undergo intermolecular hydroaminoalkylation in the presence of Ti catalyst [Ind2TiMe 2] (Ind=η5-indenyl). This new reaction offers a highly atom-efficient approach to homoallylic amines from 1,3-butadienes. Copyright
- Preuss, Till,Saak, Wolfgang,Doye, Sven
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p. 3833 - 3837
(2013/04/24)
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- COMPOUNDS FOR USE IN CANCER THERAPY
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Provided are methods and compositions for use in therapy, and in particular for treating cancer, preferably drug resistant cancer, and/or radiation resistant cancer. The compounds may be used for reducing tumor size in a mammalian subject and for inducing apoptosis in a tumor cell. The methods are effective on tumor cells that are resistant to drugs such as temozolomide, doxor-ubicin, and geldanamycin, as well as non-resistant tumor cells. Further provided are barbiturate and thiobarbiturates diene compounds for use in treating cancer, and uses, methods and compositions relating to these compounds
- -
-
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- Direct oxidative conversion of 3-aryl propionaldehydes to 3-aryl acroleins promoted by SOMO catalysis
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A new direct oxidative transformation of 3-aryl propionaldehydes to 3-aryl acroleins promoted by SOMO catalysis has been realized with high efficiency under mild reaction conditions.
- Zhu, Jin,Yu, Shunting,Lu, Wenchao,Deng, Jing,Li, Jian,Wang, Wei
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scheme or table
p. 1207 - 1209
(2012/03/26)
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- Synthesis of 1,3,5-trisubstituted pyrazolines via Zn(ii)-catalyzed double hydroamination of enynes with aryl hydrazines
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An efficient Zn(ii)-catalyzed intermolecular double hydroamination of 1,3-enynes with aryl hydrazines, for the synthesis of pyrazolines, has been discussed.
- Patil, Nitin T.,Singh, Vipender
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p. 11116 - 11118
(2011/11/29)
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- Facile synthesis of (E)-alkenyl aldehydes from allyl arenes or alkenes via Pd(II)-catalyzed direct oxygenation of allylic C-H bond
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Palladium-catalyzed oxygenation of allyl arenes or alkenes has been developed to produce (E)-alkenyl aldehydes with high yields. Allylic C-H bond cleavages occur under the mild conditions during this process. Mechanistic studies show that oxygen source is water.(Figure Presented)
- Chen, Huoji,Jiang, Huanfeng,Cai, Congbi,Dong, Jia,Fu, Wei
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supporting information; experimental part
p. 992 - 994
(2011/05/08)
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- Iron-facilitated direct oxidative C-H transformation of allyl arenes to alkenyl aldehydes
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A direct oxidative approach to alkenyl aldehydes from allyl arenes via allyl sp3 C-H functionalization was disclosed. An inexpensive iron catalyst was employed to facilitate this transformation. The mechanistic studies indicate that the cleavage of the allyl sp3 C-H bond is involved in the rate-determining step.
- Wang, Teng,Xiang, Shi-Kai,Qin, Chong,Ma, Jun-An,Zhang, Li-He,Jiao, Ning
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supporting information; experimental part
p. 3208 - 3211
(2011/06/28)
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- Cobalt-catalyzed 1,4-hydrobutadienylation of 1-aryl-1,3-dienes with 2,3-dimethyl-1,3-butadiene
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Round and round the olefin goes! A cobalt-catalyzed 1,4- hydrobutadienylation of a 1-aryl-substituted 1,3-diene with 2,3-dimethyl-1,3- butadiene yields 1,3,6-triene derivatives in excellent yield and chemoselectivity. The application of a bulky ligand (SchmalzPhos) leads to the selective formation of a single regio- and stereoisomer. Copyright
- Bohn, Martin A.,Schmidt, Anastasia,Hilt, Gerhard,Dindaroglu, Mehmet,Schmalz, Hans-Guenther
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p. 9689 - 9693
(2011/12/05)
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- Iron(III) chloride-promoted isomerization of propargyl alcohols to α,β-unsaturated carbonyl compounds
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Aryl propargyl alcohols bearing a terminal alkynyl moiety can undergo a facile iron(III) chloride-promoted transformation to the corresponding α,β-unsaturated aldehyde in good yield and excellent stereoselectivity.
- El Douhaibi, Ahmad Samih,Judeh, Zaher M. A.,Basri, Hedaya,Moussa, Ziad,Messali, Mouslim,Qi, Gao
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experimental part
p. 533 - 540
(2011/04/22)
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- Pd-catalyzed cascade Heck-Saegusa: Direct synthesis of enals from aryl iodides and allyl alcohol
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A new efficient Pd-catalyzed cascade Heck-Saegusa protocol for the synthesis of synthetically useful α,β-unsaturated aldehydes in high yields from readily available aryl iodides and allyl alcohol has been developed.
- Liu, Jie,Zhu, Jin,Jiang, Hualiang,Wang, Wei,Li, Jian
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supporting information; experimental part
p. 415 - 417
(2010/04/04)
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- ANALGESIC 5, 9 - METHANOCYCLOOCTA (b) PYRIDIN - 2 (1H) - ONE DERIVATIVES, THEIR PREPARATION METHOD AND USE
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Compounds represented by the Formula I or salts, hydrates thereof, wherein R1, R8, R11 and R12 are H or C1-4 hydrocarbonyl respectively; R2, R3, R6 and R7 are H, halogen or C1-4 hydrocarbonyl respectively; R4 is C1-6 hydrocarbonyl or Ar; or =CR4R3 is cyclopentylidene, cyclohexylidene, 1-methylpiperidyl-4-idene or indenyl-1-idene; R5 is H, 1-4 same or different F, Cl, Br, CF3, R9, OR9, NR9R10, NO2, CN, COOR9, O2CR9, CONR9R10, NR9C(O)R10, heterocyclic, aryl or groups represented by the Formula II respectively; R9 and R10 are H or C1-6 hydrocarbonyl; Ar is aromatic ring; m is 0, 1 or 2; n is 0, 1, 2, 3 or 4, for treating mammal pain, functional painful syndrome, organic painful syndrome or tissue painful syndrome, and their preparation method.
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Page/Page column 15
(2009/04/23)
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- Asymmetric 1,4-dihydroxylation of 1,3-dienes by catalytic enantioselective diboration
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(Chemical Equation Presented) Asymmetric 1,4-dihydroxylations of 1,3-dienes, and other transformations, are initiated by the Pt-catalyzed enantioselective addition of bis(pinacolato)diboron (B2(pin) 2) to conjugated dienes. The studies reported in this communication suggest that both cyclic and acyclic substrates will participate in this reaction; however, dienes which are unable to adopt the S-cis conformation are unreactive. For most substrates, 1,4-addition is the predominant pathway. In addition to oxidation to the derived 2-buten-1,4-diol, stereoselective carbonyl allylation with the intermediate bis(boronate) ester is also described.
- Burks, Heather E.,Kliman, Laura T.,Morken, James P.
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supporting information; scheme or table
p. 9134 - 9135
(2009/12/05)
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- Palladium-catalyzed oxidative tandem reaction of allylamines with aryl halides leading to α,β-unsaturated aldehydes
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A novel tandem protocol involving a Heck reaction process for the synthesis of α,β-unsaturated aldehydes has been developed. In the presence of Pd(OAc), PPh3, NaOAc, TBAB and air, N-allylbenzenamines underwent the reaction with various aryl hal
- Jiang, Tao-Shan,Li, Jin-Heng
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experimental part
p. 7236 - 7238
(2010/03/25)
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- A direct amine-palladium acetate cocatalyzed saegusa oxidation reaction of unmodified aldehydes to α,β-unsaturated aldehydes
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A direct preparation of synthetically useful α,β-unsaturated aldehydes from readily available aldehydes has been developed. The process is effectively cocatalyzed by an amine-palladium acetate to give rise to α,β-unsaturated aldehydes in moderate to good yields (41-62%). The reaction features the use of unmodified aldehydes rather than enol silyl ethers, which are used in a typical Saegusa oxidation reaction.
- Zhu, Jin,Liu, Jie,Ma, Ruoqun,Xie, Hexin,Li, Jian,Jiang, Hualiang,Wang, Wei
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supporting information; experimental part
p. 1229 - 1232
(2009/12/07)
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- Direct oxidation of β-aryl substituted aldehydes to α,β-unsaturated aldehydes promoted by an o-anisidine-Pd(OAc) 2 Co-catalyst
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An o-anisidine-Pd(OAc)2 catalytic system for the direct co-catalytic Saegusa oxidation of β-aryl substituted aldehydes to α,β-unsaturated aldehydes has been developed. The use of o-anisidine in place of (S)-diphenylprolinol made the process more simply and cost-effective. The process not only features the use of unmodified aldehydes rather than enol silyl ethers, but also gives moderate to good yields (44-72%).
- Liu, Jie,Zhu, Jin,Jiang, Hualiang,Wang, Wei,Li, Jian
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experimental part
p. 1712 - 1716
(2010/04/30)
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- Transition metal-catalyzed synthesis of pyrroles from dienyl azides
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(Chemical Equation Presented) A range of 2,5-disubstituted and 2,4,5-trisubstituted pyrroles can be synthesized from dienyl azides at room temperature using catalytic amounts of Znl2 or Rh2(O 2CC3F7)4.
- Dong, Huijun,Shen, Meihua,Redford, Joanne E.,Stokes, Benjamin J.,Pumphrey, Ashley L.,Driver, Tom G.
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p. 5191 - 5194
(2008/09/17)
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- Preparation of optically pure (3E,5E)-alkyl-2-hydroxy-6-arylhexa-3,5-dienoates by Candida parapsilosis ATCC 7330 mediated deracemisation of the racemates
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Biocatalytic deracemisation of a range of racemic (3E,5E)-alkyl-2-hydroxy-6-arylhexa-3,5-dienoates using Candida parapsilosis ATCC 7330 resulted in pure (S)-enantiomers in yields of up to 80% and ee>99%.
- Thangavel, Vaijayanthi,Chadha, Anju
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p. 4126 - 4133
(2007/10/03)
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- Chemoselective Heck arylation of acrolein diethyl acetal catalyzed by an oxime-derived palladacycle
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A dimeric 4-hydroxyacetophenone oxime-derived palladacycle has been used as a very efficient precatalyst for the chemoselective arylation of acrolein diethyl acetal to give either cinnamaldehyde derivatives or 3-arylpropanoate esters by proper choice of the reaction conditions. The synthesis of cinnamaldehyde derivatives can be performed by Heck reaction of acrolein diethyl acetal with iodo-, bromo- or chloroarenes in N,N-dimethylacetamide (DMA) using K2CO3 as base at 120°C and tetra-n-butylammonium acetate (TBAA) and KCl as additives, followed by acid workup. In the case of 3-arylpropanoate esters the corresponding arylation of acrolein diethyl acetal with iodoarenes can be performed at 90°C in aqueous DMA using (dicylohexyl)methylamine as base, whereas for bromoarenes the reaction has to be performed at 120°C using tetra-n-butylammonium bromide (TBAB) as additive. Alternatively, this process can be performed under microwave irradiation. These couplings take place in good yields and with lower catalyst loading than with palladium(II) acetate as well as in shorter reaction times and with lower excess of acrolein diethyl acetal.
- Nájera, Carmen,Botella, Luis
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p. 9688 - 9695
(2007/10/03)
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- Oxidative coupling of benzenes with α,β-unsaturated aldehydes by the Pd(OAc)2/molybdovanadophosphoric acid/O2 system
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The oxidative coupling reaction of benzene with an α,β- unsaturated aldehyde was examined by the combined catalytic system of Pd(OAc)2 with molybdovanadophosphoric acid (HPMoV) under atmospheric dioxygen. Thus, the reaction of benzene with acrolein under dioxygen (1 atm) by the use of catalytic amounts of Pd(OAc)2 and H4PMo 11VO40·26H2O in the presence of dibenzoylmethane as a ligand in propionic acid at 90 °C for 1.5 h afforded cinnamaldehyde in 59% yield and β-phenylcinnamaldehyde in 5% yield. This catalytic system was extended to the direct oxidative coupling through the C-H bond activation of various arenes with acrolein and methacrolein.
- Yamada, Tomoyuki,Sakaguchi, Satoshi,Ishii, Yasutaka
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p. 5471 - 5474
(2008/04/18)
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- An efficient palladium-catalyzed synthesis of cinnamaldehydes from acrolein diethyl acetal and aryl iodides and bromides
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(Matrix presented) The reaction of aryl iodides and bromides with acrolein diethyl acetal in the presence of Pd(OAc)2, nBu 4NOAc, K2CO3, KCl, and DMF, at 90°C until the disappearance of the acetal followed by the addition of 2 N HCl to the crude reaction mixture, affords cinnamaldehydes in good to high yields. A variety of functional groups are tolerated in the aryl halides, including ether, aldehyde, ketone, ester, dialkylamino, nitrile, and nitro groups. The presence of substituents close to the oxidative addition site does not hamper the reaction.
- Battistuzzi, Gianfranco,Cacchi, Sandro,Fabrizi, Giancarlo
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p. 777 - 780
(2007/10/03)
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- Kinetic resolution of acyclic secondary allylic silyl ethers catalyzed by chiral ketones
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Kinetic resolution of acyclic secondary allylic silyl ethers by chiral dioxiranes generated in situ from chiral ketones (R)-1 and (R)-2 and Oxone was investigated. An efficient and catalytic method has been developed for kinetic resolution of those substrates with a CCl3, tert-butyl, or CF3 group at the α-position. In particular, high selectivities (S up to 100) were observed for kinetic resolutions of racemic α-trichloromethyl allylic silyl ethers 7 and 9-15 catalyzed by ketones (R)-2. Both the recovered substrates and the resulting epoxides were obtained in high enantiomeric excess. On the basis of steric and electrostatic interactions between the chiral dioxiranes and the racemic substrates, a model was proposed to rationalize the enantioselectivities and diastereoselectivities in the chiral ketone-catalyzed kinetic resolution process.
- Yang,Jiao,Yip,Lai,Wong
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p. 4619 - 4624
(2007/10/03)
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- Electrocyclization of 3-azahexa-1,3,5-trienes: A convenient iminophosphorane-mediated preparation of 4-arylpyridines
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Aza Wittig reaction of iminophosphoranes 1, derived from α-azido- α,β-unsaturated esters and β-arylpropenals 2 leads to 4-arylpyridines in moderate to good yields.
- Molina, Pedro,Pastor, Aurelia,Vilaplana, Maria Jesus
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p. 3773 - 3776
(2007/10/02)
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