- STEREOCHEMICAL COURSE OF THE PALLADIUM-CATALYSED ARYLATION OF DISUBSTITUTED ACTIVATED ALKENES WITH BENZOYL CHLORIDE
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The palladium-catalysed arylation of ten 1,1- and 1,2-disubstituted activated alkenes with benzoyl chloride was studied.In most cases, more than one product was formed.The stereochemical course of the arylation appears to be controlled by the polarity of
- Spencer, Alwyn
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- Effects of High Pressure on the Heck Reaction. Is It Possible to Control Dehydropalladation of Alkylpalladium Intermediates Having β-Hydrogens?
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The palladium-catalyzed arylation of acrylates, so-called the Heck reaction, was accelerated and partially controlled under high pressure conditions.
- Sugihara, Takumichi,Takebayashi, Masahiro,Kaneko, Chikara
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- Synthesis and reactivity of platinum vinylcarbene complexes prepared from activation of propargyl alcohols
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Platinum vinylcarbene complexes are potentially useful for organometallic synthesis and catalysis, but have been rarely studied. This work reports a convenient route to make platinum vinylcarbene complexes. Treatment of [PtCl2(PPh3)]2 with propargyl alcohols HC≡CC(OH)RR’ (RR’ = Ph2, cyclo-C6H10(OH), (iPr)(C≡CTMS) and (H)(Ph)) in the presence of EtOH produced the vinylcarbene complexes trans-PtCl2{ = C(OEt)-CH=CRR’}(PPh3). Under similar condition, [PtCl2(PPh3)]2 reacted with HC≡CC(OH)Me2 to give cis-PtCl2{ = C(OEt)-CH=CMe2}(PPh3). Complex trans-PtCl2{ = C(OEt)-CH=CPh2}(PPh3) readily undergo a metathesis reaction with NaI to give trans-PtI2{ = C(OEt)-CH=CPh2}(PPh3) which can isomerize to cis-PtI2{ = C(OEt)-CH=CPh2}(PPh3). Complex trans-PtCl2{ = C(OEt)-CH=CPh2}(PPh3) reacted with PPh3 to give EtCl and the acyl complex trans-PtCl{C(O)CH=CPh2}(PPh3)2, which can undergo a decarbonylation reaction to give PtCl(CH=CPh2)(PPh3)2.
- Ruan, Wenqing,Shi, Chuan,Sung, Herman H.Y.,Williams, Ian D.,Jia, Guochen
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- Synthesis of 1,1-Diborylalkenes through a Br?nsted Base Catalyzed Reaction between Terminal Alkynes and Bis(pinacolato)diboron
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A method for the synthesis of 1,1-diborylalkenes through a Br?nsted base catalyzed reaction between terminal alkynes and bis(pinacolato)diboron has been developed. The procedure allows direct synthesis of functionalized 1,1-diborylalkenes from various ter
- Morinaga, Akira,Nagao, Kazunori,Ohmiya, Hirohisa,Sawamura, Masaya
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- Controlling Enantioselectivity and Diastereoselectivity in Radical Cascade Cyclization for Construction of Bicyclic Structures
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Radical cascade cyclization reactions are highly attractive synthetic tools for the construction of polycyclic molecules in organic synthesis. While it has been successfully implemented in diastereoselective synthesis of natural products and other complex compounds, radical cascade cyclization faces a major challenge of controlling enantioselectivity. As the first application of metalloradical catalysis (MRC) for controlling enantioselectivity as well as diastereoselectivity in radical cascade cyclization, we herein report the development of a Co(II)-based catalytic system for asymmetric radical bicyclization of 1,6-enynes with diazo compounds. Through the fine-tuning of D2-symmetric chiral amidoporphyrins as the supporting ligands, the Co(II)-catalyzed radical cascade process, which proceeds in a single operation under mild conditions, enables asymmetric construction of multisubstituted cyclopropane-fused tetrahydrofurans bearing three contiguous stereogenic centers, including two all-carbon quaternary centers, in high yields with excellent stereoselectivities. Combined computational and experimental studies have shed light on the underlying stepwise radical mechanism for this new Co(II)-based cascade bicyclization that involves the relay of several Co-supported C-centered radical intermediates, including α-, β-, γ-, and ?-metalloalkyl radicals. The resulting enantioenriched cyclopropane-fused tetrahydrofurans that contain a trisubstituted vinyl group at the bridgehead, as showcased in several stereospecific transformations, may serve as useful intermediates for stereoselective organic synthesis. The successful demonstration of this new asymmetric radical process via Co(II)-MRC points out a potentially general approach for controlling enantioselectivity as well as diastereoselectivity in synthetically attractive radical cascade reactions.
- Lee, Wan-Chen Cindy,Mckillop, Alexander M.,Wang, Duo-Sheng,Zhang, Congzhe,Zhang, X. Peter
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supporting information
p. 11130 - 11140
(2021/07/31)
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- Palladium-Catalyzed Allyl-Allyl Reductive Coupling of Allylamines or Allylic Alcohols with H2as Sole Reductant
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Catalytic carbon-carbon bond formation building on reductive coupling is a powerful method for the preparation of organic compounds. The identification of environmentally benign reductants is key for establishing an efficient reductive coupling reaction. Herein an efficient strategy enabling H2 as the sole reductant for the palladium-catalyzed allyl-allyl reductive coupling reaction is described. A wide range of allylamines and allylic alcohols as well as allylic ethers proceed smoothly to deliver the C-C coupling products under 1 atm of H2. Kinetic studies suggested that the dinuclear palladium species was involved in the catalytic cycle.
- Zhou, Xibing,Zhang, Guoying,Huang, Renbin,Huang, Hanmin
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supporting information
p. 365 - 369
(2021/01/26)
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- Synthesis method of beta-chloro acid ester and alpha, beta-unsaturated acid ester compound
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The invention belongs to the technical field of organic chemistry, and particularly relates to a synthesis method of beta-chloro acid ester and an alpha, beta-unsaturated acid ester compound. The structure of the compound is characterized by 1H NMR and 13C NMR and is confirmed. The method comprises the steps of by taking acetonitrile as a solvent, carrying out fragmentation on olefin, chlorooxalic acid monoester and 2, 6-dimethyl pyridine under a photocatalytic condition to generate an alkoxyacyl free radical intermediate, carrying out free radical addition reaction on the alkoxyacyl free radical intermediate and the olefin to generate carbon free radicals, then carrying out chlorination reaction to obtain the beta-chloro acid ester compound, and carrying out dehydrochlorination reaction under a DBU condition to generate the alpha, beta-unsaturated acid ester compound. The preparation method of the compound disclosed by the invention has the advantages of starting from olefin, being mild in condition, simple and efficient, strong in functional group compatibility and wide in substrate application range, and various beta-chloro acid ester and alpha, beta-unsaturated acid ester compounds can be synthesized from highly commercialized raw materials. On the basis of photoreaction of fluid chemistry, a target product can also be obtained with a relatively good yield, and the method has very good industrial and medicinal chemistry application values.
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Paragraph 0128-0132
(2021/08/11)
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- Photoinduced Oxidative Alkoxycarbonylation of Alkenes with Alkyl Formates
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A photoinduced oxidative alkoxycarbonylation of alkenes initiated by intermolecular addition of alkoxycarbonyl radicals has been demonstrated. Employing alkyl formates as alkoxycarbonyl radical sources, a range of α,β-unsaturated esters were obtained with good regioselectivity and E selectivity under ambient conditions.
- Tang, Wan-Ying,Chen, Ling,Zheng, Ming,Zhan, Le-Wu,Hou, Jing,Li, Bin-Dong
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supporting information
p. 3939 - 3943
(2021/05/26)
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- Recyclable and reusable PdCl2(PPh3)2/PEG-400/H2O system for the hydrophenylation of alkynes with sodium tetraphenylborate
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A stable and efficient PdCl2(PPh3)2/PEG-400/H2O catalytic system for the hydrophenylation reaction of alkynes has been developed. In the presence of 3 mol% PdCl2(PPh3)2 and 2 equiv. of HOAc, the hydrophenylation of both terminal and internal alkynes with sodium tetraphenylborate proceeded smoothly in a mixture of PEG-400 and water at room temperature or 50 °C to afford a variety of phenyl-substituted alkenes in moderate to high yields. The isolation of the products was easily performed by extraction with petroleum ether, and the PdCl2(PPh3)2/PEG-400/H2O system could be readily recycled and reused six times without apparent loss of catalytic activity.
- Liu, Rong,Zhang, Tingli,Huang, Bin,Cai, Mingzhong
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p. 172 - 178
(2020/07/04)
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- DERIVATIVES OF PIPERLONGUMINE AND USES THEREOF
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The present invention relates to a group of 1-[(E)-3-(3,4,5-trimethoxyphenyl)prop-2-enoyl]-2,3-dihydropyridin-6-one (piperlongumine) derivatives, analogs and pharmaceutically acceptable salts thereof. The present invention also relates to a pharmaceutical composition and formulation containing a derivative of piperlongumine; and use of the derivatives and analogs for treating cancer, reducing inflammation and/or treating an autoimmune or inflammatory disease.
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Paragraph 0525-0527
(2020/12/13)
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- Synthesis and characterization of unsaturated diacyl and alkyl-acyl piperazine derivatives
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The aim of this study is to obtain new unsaturated piperazine compounds by the reactions of piperazine (1a) and piperazine derivatives (1b–1d) with acylation reactive groups (2a–2j). Methacryloyl piperazine (1b) was synthesized from the reaction of methacrylic anhydride with piperazine (1a). Acyl chlorides (2b–2d) were prepared from the reaction of thionyl chloride with carboxylic acids (3a–3c) obtained as a result of the reaction with malonic acid and suitable aldehyde (5-methylfuran-2-carbaldehyde for 3a, cinnamaldehyde for 3b, and thiophene-2-carbaldehyde for 3c), respectively, by literature methods. Acyl chlorides 2e and 2f were obtained from the reaction of commercially purchased carboxylic acids 3d and 3e with thionyl chloride. Acyl chlorides (2g–2j) were synthesized from the reaction of thionyl chloride with carboxylic acids (3d–3g) transformed from hydrolyzation of esters (4a–4d) obtained as a result of the reaction of triethyl phosphonoacetate with a suitable ketone (acetophenone for 4a, benzophenone for 4b, 1-(5-methylfuran-2-yl)ethan-1-one for 4c, and 1-(thiophen-2-yl)ethan-1-one for 4d), respectively, by literature methods. Unsaturated piperazine derivatives 5a and 5b were obtained from the reaction of 1b with 2b and 2e, respectively. In addition, from the reaction of 1b and acyl chlorides (2b–2j), unsaturated piperazines (5c–5k) were synthesized in medium to good yields (63%–84%). Also, 5l–5g and 5r–5w were obtained from the reaction of allyl piperazine (2c) and cinnamyl piperazine (2d) with acyl chlorides (2a–2f).
- Sari, Sait,ünalan, Seda,Yilmaz, Mehmet
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p. 1656 - 1671
(2020/01/03)
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- Catalytic hydrogenation of α,β-unsaturated carboxylic acid derivatives using copper(i)/N-heterocyclic carbene complexes
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A simple and air-stable copper(i)/N-heterocyclic carbene complex enables the catalytic hydrogenation of enoates and enamides, hitherto unreactive substrates employing homogeneous copper catalysis and H2 as a terminal reducing agent. This atom economic transformation replaces commonly employed hydrosilanes and can also be carried out in an asymmetric fashion.
- Zimmermann, Birte M.,Kobosil, Sarah C. K.,Teichert, Johannes F.
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supporting information
p. 2293 - 2296
(2019/02/27)
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- DERIVATIVES OF PIPERLONGUMINE AND USES THEREOF
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The present invention relates to a group of 1-[(E)-3-(3,4,5-trimethoxyphenyl)prop-2-enoyl]-2,3- dihydropyridin-6-one (piperlongumine) derivatives, analogs and pharmaceutically acceptable salts thereof. The present invention also relates to processes for preparing the same; a pharmaceutical composition and formulation containing a derivative of piperlogumine; and use of the derivatives and analogs for treating cancer.
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Page/Page column 120; 121
(2019/06/11)
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- Arene Trifunctionalization with Highly Fused Ring Systems through a Domino Aryne Nucleophilic and Diels–Alder Cascade
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A convenient and efficient domino aryne process was developed under transition-metal-free conditions to generate a range of tetra- and pentacyclic ring systems. This transformation was realized via a 1,2-benzdiyne through a nucleophilic and Diels–Alder reaction cascade using styrene as the diene moiety. Three new chemical bonds, namely one C?N and two C?C bonds, and two benzofused rings could be constructed concomitantly, which was made possible by distinct chemoselective control at both the 1,2-aryne and 2,3-aryne stages. Moreover, in-depth studies were carried out on the domino aryne precursors and controlling the diastereoselectivity.
- He, Jia,Jia, Zizi,Tan, Hongcheng,Luo, Xiaohua,Qiu, Dachuan,Shi, Jiarong,Xu, Hai,Li, Yang
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supporting information
p. 18513 - 18518
(2019/11/19)
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- Mechanochemical Oxidative Heck Coupling of Activated and Unactivated Alkenes: A Chemo-, Regio- and Stereo-Controlled Synthesis of Alkenylbenzenes
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In this work, we present an efficient mechanochemical strategy for chemo-, regio- and stereo-selective oxidative Heck coupling of readily accessible arylboron reagents/heteroaromatics with cyclic and acyclic olefins. Mono- and bis-arylation were achieved without the need of ligands, directing groups or prefunctionalized alkenes, and the reaction chemo-selectivity could be controlled by tuning of the oxidative system. This protocol offers the synthesis of alkenylbenzenes in broad substrate scope, satisfactory yields and excellent selectivity even in the gram scale. (Figure presented.).
- Yu, Jingbo,Shou, Haowen,Yu, Wangyang,Chen, Haodong,Su, Weike
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supporting information
p. 5133 - 5139
(2019/11/11)
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- Scalable Electrochemical Dehydrogenative Lactonization of C(sp2/sp3)-H Bonds
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A practical, electrochemical method is developed for the direct dehydrogenative lactonization of C(sp2/sp3)-H bonds under external oxidant- and metal-free conditions, delivering diverse lactones, including coumarin derivatives with excellent regioselectivity. The scalable nature of this newly developed electrochemical process was demonstrated on a 40 g scale following an operationally simple protocol. The remote lactonization of C(sp3)-H bonds would constitute an important synthetic advance toward electrochemical C-O bond formation.
- Zhang, Sheng,Li, Lijun,Wang, Huiqiao,Li, Qian,Liu, Wenmin,Xu, Kun,Zeng, Chengchu
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supporting information
p. 252 - 255
(2018/01/17)
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- Transition-Metal-Free Formylation of Allylzinc Reagents Leading to α-Quaternary Aldehydes
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The first example of formylation of allylzinc reagents using S-phenyl thioformate is presented. The reaction proceeded under mild conditions without any transition-metal catalyst, forming quaternary carbon centers with reactive functionalities, such as formyl and vinyl groups. Moreover, Barbier-type formylation of an allylic bromide with a sterically demanding thioformate was achieved. As a preliminary result, asymmetric formylation was conducted using a menthol-derived chiral thioformate.
- Haraguchi, Ryosuke,Kusakabe, Akinori,Mizutani, Nakaba,Fukuzawa, Shin-Ichi
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supporting information
p. 1613 - 1616
(2018/03/23)
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- Trans -Hydroboration vs. 1,2-reduction: Divergent reactivity of ynones and ynoates in Lewis-base-catalyzed reactions with pinacolborane
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Ynones and ynoates react with pinacolborane in a divergent manner in the presence of nucleophilic phosphine catalysts. Ynones are transformed to the corresponding propargyl alcohols in good yields with high regio- and chemoselectivity. Ynoates undergo highly regio- and stereoselective trans-hydroboration to produce E-vinylboronates. Impressive divergence in reactivity of ynones and ynoates can be traced back to the mechanistic aspects of 1,2-reduction and trans-hydroboration. A comparative analysis of the two pathways paints a complex picture in which different reaction rates control selectivity in these seemingly unrelated processes and explains how sufficiently acidic protons in the reaction mixtures can be used to steer the selectivity in different directions.
- Zi, You,Sch?mberg, Fritz,Seifert, Fabian,G?rls, Helmar,Vilotijevic, Ivan
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p. 6341 - 6349
(2018/09/10)
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- Palladium catalyzed Heck-arylation/cyclization cascade: An environmentally benign and efficient synthesis of 4-arylcoumarins in water
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An environmentally benign and efficient approach for the synthesis of 4-arylcoumarins from ortho-hydroxy cinnamate ester derivatives with aryl iodides was developed in water under aerobic conditions. This transformation proceeds through a palladium catalyzed Heck-arylation/cyclization cascade reaction. The present protocol features a wide substrate scope and readily available starting materials to afford the desired products in high to excellent yields.
- Chen, Junmin,Liu, Wei,Zhou, Liandi,Zhao, Yongli
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supporting information
p. 2526 - 2531
(2018/05/28)
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- Employing Water as the Hydride Source in Synthesis: A Case Study of Diboron Mediated Alkyne Hydroarylation
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We present an approach to utilize water as the hydride source via Pd(II)/Pd(0) catalysis. As a case study, we have achieved a diboron mediated Pd(II)-catalyzed hydroarylation of alkynes using arylboronic acids. This approach not only complements conventional reactivity of Pd via Pd(0)/Pd(II) cycle for the hydroarylation but also utilizes water as the hydride source. We believe this would particularly be beneficial in utilizing water as a reagent.
- Rao, Santhosh,Joy, M. Nibin,Prabhu, Kandikere Ramaiah
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p. 13707 - 13715
(2018/11/30)
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- Pd(II)/Bipyridine-Catalyzed Conjugate Addition of Arylboronic Acids to α,β-Unsaturated Carboxylic Acids. Synthesis of β-Quaternary Carbons Substituted Carboxylic Acids
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Pd(II)/bipyridine-catalyzed conjugate addition of arylboronic acids to α,β-unsaturated carboxylic acids (including β,β-disubstituted acrylic acids) was developed and optimized, which provided a mild and convenient method for the highly challenging synthesis of β-quaternary carbons substituted carboxylic acids.
- Liu, Rui,Yang, Zhenyu,Ni, Yuxin,Song, Kaixuan,Shen, Kai,Lin, Shaohui,Pan, Qinmin
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p. 8023 - 8030
(2017/08/14)
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- Rhodium-catalyzed C(sp2)-H addition of arylboronic acids to alkynes using a boron-based, convertible ortho-directing group
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Temporary modification of a boronyl group with pyrazoryl-aniline allowed insertion of arylpropiolates and diphenylacet-ylenes into the o-C-H bond of arylboronic acids in the presence of rhodium catalysts, giving 3,3-diarylacrylates and triarylethene conta
- Yamamoto, Takeshi,Ishibashi, Aoi,Suginome, Michinori
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supporting information
p. 1169 - 1172
(2017/08/07)
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- Photoinduced, Copper-Promoted Regio- and Stereoselective Decarboxylative Alkylation of α,β-Unsaturated Acids with Alkyl Iodides
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The first example of UV light-induced, copper-catalyzed regio- and stereoselective decarboxylative coupling of α,β-unsaturated acids with alkyl iodides was reported. Under standard conditions, the 1°, 2°, and 3° alkyl iodides proceeded smoothly with the E-selective alkenes obtained in uniformly good yields and high stereoselectivities.
- Wang, Chao,Lei, Yingjie,Guo, Mengzhun,Shang, Qinyu,Liu, Hong,Xu, Zhaoqing,Wang, Rui
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supporting information
p. 6412 - 6415
(2017/12/08)
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- S,O-Ligand-Promoted Palladium-Catalyzed C-H Functionalization Reactions of Nondirected Arenes
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Pd(II)-catalyzed C-H functionalization of nondirected arenes has been realized using an inexpensive and easily accessible type of bidentate S,O-ligand. The catalytic system shows high efficiency in the C-H olefination reaction of electron-rich and electron-poor arenes. This methodology is operationally simple, scalable, and can be used in late-stage functionalization of complex molecules. The broad applicability of this catalyst has been showcased in other transformations such as Pd(II)-catalyzed C-H acetoxylation and allylation reactions.
- Naksomboon, Kananat,Valderas, Carolina,Gómez-Martínez, Melania,álvarez-Casao, Yolanda,Fernández-Ibá?ez, M. ángeles
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p. 6342 - 6346
(2017/09/15)
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- The synthesis of α,α-disubstituted α-amino acids via ichikawa rearrangement
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An approach to α,α-disubstituted α-amino acids is reported. The key step is allyl cyanate-to-isocyanate rearrangement. As demonstrated, the resultant allyl isocyanates can be directly trapped with various nucleophiles, for instance, alcohols, amines, and organometallic reagents, to provide a broad range of N-functionalized allylamines. The developed method has been successfully applied in the synthesis of two bioactive peptides: 2-aminoadamantane-2-carboxylic acid derived P2X7-evoked glutamate release inhibitor and 4-amino-tetrahydropyranyl-4-carboxylic acid derived dipeptide GSK-2793660, which is currently in clinical trials as cathepsin C inhibitor for the treatment of cystic fibrosis, noncystic fibrosis bronchiectasis, ANCA-associated vasculitis and bronchiectasis.
- Szczes?niak, Piotr,Pieczykolan, Micha?,Stecko, Sebastian
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p. 1057 - 1074
(2016/02/19)
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- Copper(I)-Catalyzed Allylic Substitutions with a Hydride Nucleophile
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An easily accessible copper(I)/N-heterocyclic carbene (NHC) complex enables a regioselective hydride transfer to allylic bromides, an allylic reduction. The resulting aryl- and alkyl-substituted branched α-olefins, which are valuable building blocks for synthesis, are obtained in good yields and regioselectivity. A commercially available silane, (TMSO)2Si(Me)H, is employed as hydride source. This protocol offers a unified alternative to the established metal-catalyzed allylic substitutions with carbon nucleophiles, as no adaption of the catalyst to the nature of the nucleophile is required.
- Nguyen, T. N. Thanh,Thiel, Niklas O.,Pape, Felix,Teichert, Johannes F.
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supporting information
p. 2455 - 2458
(2016/06/09)
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- Enantioselective Oxidative Rearrangements with Chiral Hypervalent Iodine Reagents
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A stereoselective hypervalent iodine-promoted oxidative rearrangement of 1,1-disubstituted alkenes has been developed. This practically simple protocol provides access to enantioenriched α-arylated ketones without the use of transition metals from readily
- Brown, Michael,Kumar, Ravi,Rehbein, Julia,Wirth, Thomas
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supporting information
p. 4030 - 4035
(2016/03/16)
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- Pd-Catalyzed α-Selective C-H Functionalization of Olefins: En Route to 4-Imino-β-Lactams
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Pd-catalyzed α-olefinic C-H activation of simple α,β-unsaturated olefins has been developed. 4-imino-β-lactam derivatives were readily synthesized via activation of α-olefinic C-H bonds with excellent cis stereoselectivity. A wide range of heterocycles at the β-position are compatible with this reaction. The product of 4-imino-β-lactam derivatives can be readily converted to 2-aminoquinoline which exists extensively in pharmaceutical drugs and natural products.
- Kong, Wei-Jun,Liu, Yue-Jin,Xu, Hui,Chen, Yan-Qiao,Dai, Hui-Xiong,Yu, Jin-Quan
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supporting information
p. 2146 - 2149
(2016/03/05)
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- New orally active diphenylmethyl-based ester analogues of dihydroartemisinin: Synthesis and antimalarial assessment against multidrug-resistant Plasmodium yoelii nigeriensis in mice
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A new series of ester analogues of artemisinin 8a–f, incorporating diphenylmethyl as pharmacologically privileged substructure, and 8g–j have been prepared and evaluated for their antimalarial activity against multidrug-resistant (MDR) Plasmodium yoelii nigeriensis in Swiss mice via oral route. These diphenylmethyl-based ester analogues 8a–f were found to be 2–4 folds more active than the antimalarial drugs β-arteether 4 and artesunic acid 5. Ester 8a, the most active compound of the series, provided complete protection to the infected mice at 24?mg/kg?×?4?days as well as 12?mg/kg?×?4?days, respectively. In this model β-arteether provided 100% and 20% protection at 48?mg/kg?×?4?days and 24?mg/kg?×?4?days, respectively.
- Chaudhary, Sandeep,Naikade, Niraj K.,Tiwari, Mohit K.,Yadav, Lalit,Shyamlal, Bharti Rajesh K.,Puri, Sunil K.
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p. 1536 - 1541
(2016/07/27)
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- Palladium(II) oxide impregnated on magnetite as a catalyst for the synthesis of 4-arylcoumarins: Via a Heck-arylation/cyclization process
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Heck-arylation/cyclization was achieved using heterogeneous palladium(ii) oxide impregnated on magnetite catalyst (2.5 mol%) with a lower catalyst loading than that reported for similar processes. Ethanol was used as a non-toxic and bio-renewable solvent. Good yields were afforded using a broad range of substrates (40-98%). The catalyst could be partially recycled, and analyses confirmed the almost total reduction of palladium(ii) oxide to palladium(0) as well as the iodine poissoning effect, which is the main barrier to complete recyclability.
- Pérez, Juana M.,Cano, Rafael,McGlacken, Gerard P.,Ramón, Diego J.
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p. 36932 - 36941
(2016/05/24)
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- Preparation method of alpha-beta-unsaturated carbonyl compound
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The invention relates to a preparation method of an alpha-beta-unsaturated carbonyl compound, in particular to a method in which the alpha-beta-unsaturated carbonyl compound is prepared from substitute propargyl alcohol in a mode that positive ion modified imvite serves as a catalyst, the substitute propargyl alcohol serves as the raw material, and Meyer-Schuster rearrangement is utilized. According to the method, the substrate is wide in application range, the catalyst is cheap, easy to manufacture, stable, free of pollution to the environment and capable of being recycled, the reaction yield is high, stereoselectivity is good, and an E-type product can be obtained in a singular mode.
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Paragraph 0111; 0112; 0113; 0114; 0115; 0116; 0117; 0118
(2016/10/09)
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- Phosphorylated cyclopropanes in the synthesis of α-alkylidene-γ-butyrolactones: Total synthesis of (±)-savinin, (±)-gadain and (±)-peperomin e
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Phosphorylated cyclopropanes, generated via the Rh(ii)-catalysed intramolecular cyclopropanation of α-(diethoxyphosphoryl)acetates, have been found to be useful precursors in the synthesis of α-alkylidene-γ-butyrolactones. These cyclopropyl intermediates undergo regioselective reductive ring-opening and subsequent Horner-Wadsworth-Emmons olefination to complete the synthesis. Total syntheses of (±)-savinin and (±)-gadain, as well as the first total synthesis of (±)-peperomin E, are all described using this method.
- Lloyd, Matthew G.,Taylor, Richard J. K.,Unsworth, William P.
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supporting information
p. 8971 - 8988
(2016/10/09)
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- Biphilic organophosphorus catalysis: Regioselective reductive transposition of allylic bromides via PIII/PV redox cycling
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We report that a regioselective reductive transposition of primary allylic bromides is catalyzed by a biphilic organophosphorus (phosphetane) catalyst. Spectroscopic evidence supports the formation of a pentacoordinate (σ5-P) hydridophosphorane as a key reactive intermediate. Kinetics experiments and computational modeling are consistent with a unimolecular decomposition of the σ5-P hydridophosphorane via a concerted cyclic transition structure that delivers the observed allylic transposition and completes a novel PIII/PV redox catalytic cycle. These results broaden the growing repertoire of reactions catalyzed within the PIII/PV redox couple and suggest additional opportunities for organophosphorus catalysis in a biphilic mode.
- Reichl, Kyle D.,Dunn, Nicole L.,Fastuca, Nicholas J.,Radosevich, Alexander T.
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supporting information
p. 5292 - 5295
(2015/05/13)
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- SUBSTITUTED HETEROCYCLIC DERIVATIVES AS GPR AGONISTS AND USES THEREOF
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The present invention generally relates to substituted heterocyclic derivatives (the compounds of Formula (I)), processes for their preparation, pharmaceutical compositions containing said compounds, their use as G-protein coupled receptor (GPR) agonists, particularly as GPR40 agonists and methods of using these compounds in the treatment of GPR40 mediated diseases or conditions such as Type 2 diabetes, obesity, dyslipidemia, hyperlipidemia, hypercholesterolemia, and hypertriglyceridemia.
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Page/Page column 147; 148
(2015/03/16)
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- Single-site palladium(II) catalyst for oxidative heck reaction: Catalytic performance and kinetic investigations
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The development of organometallic single-site catalysts (SSCs) has inspired the designs of new heterogeneous catalysts with high efficiency. Nevertheless, the application of SSCs in certain modern organic reactions, such as C-C bond formation reactions, has still been less investigated. In this study, a single-site Pd(II) catalyst was developed, where 2,2′-bipyridine-grafted periodic mesoporous organosilica (PMO) was employed as the support of a Pd(II) complex. The overall performance of the single-site Pd(II) catalyst in the oxidative Heck reaction was then investigated. The investigation results show that the catalyst displays over 99% selectivity for the product formation with high reaction yield. Kinetic profiles further confirm its high catalytic efficiency, showing that the rate constant is nearly 40 times higher than that for the free Pd(II) salt. X-ray absorption spectroscopy reveals that the catalyst has remarkable lifetime and recyclability.
- Duan, Hui,Li, Menghuan,Zhang, Guanghui,Gallagher, James R.,Huang, Zhiliang,Sun, Yu,Luo, Zhong,Chen, Hongzhong,Miller, Jeffrey T.,Zou, Ruqiang,Lei, Aiwen,Zhao, Yanli
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p. 3752 - 3759
(2015/06/16)
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- Synthesis of 2-Arylpyridopyrimidinones, 6-Aryluracils, and Tri- and Tetrasubstituted Conjugated Alkenes via Pd-Catalyzed Enolic C-O Bond Activation-Arylation
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A new and efficient approach for the synthesis of biologically important 2-aryl-4H-pyrido[1,2-a]pyrimidin-4-ones and 6-aryluracils via previously unknown Pd-catalyzed enolic C-OH activation-arylation of pyridopyrimidin-2,4-diones and barbituric acids, res
- Guchhait, Sankar K.,Priyadarshani, Garima
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p. 6342 - 6349
(2015/06/30)
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- Hypervalent iodine reagents enable chemoselective deboronative/decarboxylative alkenylation by photoredox catalysis
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Chemoselective C(sp3)-C(sp2) coupling reactions under mild reaction conditions are useful for synthesizing alkyl-substituted alkenes having sensitive functional groups. Reported here is a visible-light-induced chemoselective alkenylation through a deboronation/decarboxylation sequence under neutral aqueous reaction conditions at room temperature. This reaction represents the first hypervalent-iodineenabled radical decarboxylative alkenylation reaction, and a novel benziodoxole-vinyl carboxylic acid reaction intermediate was isolated. This C(sp3/sup>)-C(sp2) coupling reaction leads to aryl-and acyl-substituted alkenes containing various sensitive functional groups. The excellent chemoselectivity, stable reactants, and neutral aqueous reaction conditions of the reaction suggest future biomolecule applications.
- Huang, Hanchu,Jia, Kunfang,Chen, Yiyun
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supporting information
p. 1881 - 1884
(2015/02/19)
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- Highly enantioselective hydrogenation of steric hindrance enones catalyzed by Ru complexes with chiral diamine and achiral phosphane
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An asymmetric hydrogenation of sterically hindered β,β- disubstituted enones has been well-established by using a ruthenium complex composed of an achiral diphosphane and a chiral diamine as catalyst, wherein the carbonyl group was selectively hydrogenated to give a wide range of chiral allylic alcohols with high levels of enantioselectivity and complete chemoselectivity.
- Chen, Xiangning,Zhou, Han,Zhang, Kunyu,Li, Jiawen,Huang, Hanmin
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supporting information
p. 3912 - 3915
(2014/08/18)
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- Synthesis of coumarins via PIDA/I2-mediated oxidative cyclization of substituted phenylacrylic acids
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A variety of functionalized coumarins were synthesized from substituted phenylacrylic acids via PIDA/I2-mediated and irradiation-promoted oxidative carbon-oxygen bond formation. Our studies show that the oxygen in the pendant carboxylic acid group cyclizes favorably to the aryl ring that is cis to it. The main advantages of this method include good functional group tolerance and the transition-metal-free characteristic. The Royal Society of Chemistry 2013.
- Li, Jinming,Chen, Huiyu,Zhang-Negrerie, Daisy,Du, Yunfei,Zhao, Kang
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p. 4311 - 4320
(2013/04/24)
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- Synthesis of substituted nitroolefins: A copper catalyzed nitrodecarboxylation of unsaturated carboxylic acids
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A novel, mild and convenient method for the nitrodecarboxylation of substituted cinnamic acid derivatives to their nitroolefins is achieved using a catalytic amount of CuCl (10 mol%) and tert-butyl nitrite (2 equiv.) as a nitrating agent in the presence of air. This reaction provides a useful method for the synthesis of β,β-disubstituted nitroolefin derivatives, which are generally difficult to access from other conventional methods. Additionally, this reaction is selective as the E-isomer of the acid derivatives furnishes the corresponding E-nitroolefins. One more salient feature of the method is, unlike other methods, no metal nitrates or HNO3 are employed for the transformation.
- Rokade, Balaji V.,Prabhu, Kandikere Ramaiah
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supporting information
p. 6713 - 6716
(2013/10/01)
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- Metabolism-guided discovery of a potent and orally bioavailable urea-based calcimimetic for the treatment of secondary hyperparathyroidism
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A series of urea based calcimimetics was optimized for potency and oral bioavailability. Crucial to this process was overcoming the poor pharmacokinetic properties of lead thiazole 1. Metabolism-guided modifications, characterized by the use of metabolite identification (ID) and measurement of time dependent inhibition (TDI) of CYP3A4, were essential to finding a compound suitable for oral dosing. Calcimimetic 18 exhibited excellent in vivo potency in a 5/6 nephrectomized rat model and cross-species pharmacokinetics.
- Wehn, Paul M.,Harrington, Paul E.,Carlson, Timothy J.,Davis, James,Deprez, Pierre,Fotsch, Christopher H.,Grillo, Mark P.,Lu, Jenny Ying-Lin,Morony, Sean,Pattabiraman, Kanaka,Poon, Steve F.,Reagan, Jeff D.,St. Jean Jr., David J.,Temal, Taoues,Wang, Minghan,Yang, Yuhua,Henley III, Charles,Lively, Sarah E.
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p. 6625 - 6628
(2014/01/06)
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- Controlled mono- and double-Heck reaction catalyzed by a dicarbene dipalladium complex
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The phosphine-free mono- and double-Heck reaction of terminal olefins with electron-deficient and electron-rich aryl halides (iodides and bromides) is described. These reactions are catalyzed by the dicarbene dipalladium complex 1 by controlling the stoichiometry of the aryl halide and the olefine, the loading of the palladium catalyst, as well as using different base, and with or without additive. The procedure of double-Heck reaction allows β,β- diarylation and β,β′-diarylation of terminal olefins and affords trisubstituted olefins in good to excellent yields.
- Li, Yunfei,Liu, Gang,Cao, Changsheng,Wang, Shuzhan,Li, Yuling,Pang, Guangsheng,Shi, Yanhui
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p. 6241 - 6250
(2013/07/27)
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- Synthesis, structure, and reactivity of dicarbene dipalladium complexes
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A series of imidazole-based and benzimidazole-based di-NHC dipalladium complexes with alkyl bridges of different chain lengths were prepared. All complexes were fully characterized by NMR spectroscopy and elemental analyses. The crystal structures of three complexes were determined by X-ray diffraction. X-ray studies show the length of linker effects the solid structure of these complexes and π-π stacking plays an important role for the configuration of NHC-Pd-Py subunits. The activity of NHC-palladium complexes was investigated in the mono- and double-Heck reactions, and the imidazole-based palladium complex bearing the shortest ethylene bridge shows the best activity and selectivity in both reactions. Copyright
- Li, Yunfei,Yang, Longguang,Chen, Qian,Cao, Changsheng,Guan, Pei,Pang, Guangsheng,Shi, Yanhui
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p. 575 - 581
(2013/04/24)
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- Pd-arylurea complexes for the Heck arylation of crotonic and cinnamic substrates
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A catalyst consisting of the 1:2 complex of Pd(OAc)2 (1 mol %) with N-(4-carbethoxy)-phenylurea promotes the Heck arylation of a range of crotonic and cinnamic substrates, including aldehydes, ketones, esters, and nitriles, with electron-rich - but not electron-deficient - aryl iodides.
- Smith, Matthew R.,Kim, Jung Yun,Ciufolini, Marco A.
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supporting information
p. 2042 - 2045
(2013/04/24)
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- Selective reactivity of electron-rich aryl iodides in the Heck arylation of disubstituted alkenes catalyzed by palladium-arylurea complexes
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A catalyst consisting of 1 mol % of the 1:2 complex of Pd(OAc)2 with N-(4-carbethoxyphenyl)urea promotes the Heck arylation of 2- or 3-substituted, conjugated esters, nitriles, aldehydes, and ketones (an uncharacteristically broad range of substrates), but only with electron-rich aryl iodides (an uncharacteristically narrow range of halides).
- Smith, Matthew R.,Jang, Young Jin,Kim, Jung Yun,Ciufolini, Marco A.
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p. 10139 - 10151
(2013/11/06)
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- A newly-designed PE-supported arsine for efficient and practical catalytic Wittig olefination
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A newly designed PE-supported arsine has been developed as an excellent catalyst for catalytic Wittig-type olefination. Simple ketones, in particular inactive ketones prove to be suitable substrates for the first time. This reaction provides an easy access to di-, tri-, and tetra-substituted olefins in high yield.
- Wang, Peng,Liu, Chun-Rong,Sun, Xiu-Li,Chen, Shuai-Shuai,Li, Jun-Fang,Xie, Zuowei,Tang, Yong
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supporting information; experimental part
p. 290 - 292
(2012/01/06)
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- New Pd(II) binuclear complexes as effective catalysts in oxidative-heck reaction using arylboronic acid derivatives
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A series of new binuclear Pd(II) complexes based on chelating diimines and bridging diphosphine or diimine ligands have been synthesized and characterized successfully. The formula of the new complexes are [Pd2(mbyp) 2(DPA)2](PF6)4 (1), [Pd 2(mbyp)2(DPE)2] (PF6)4 (2), [Pd2(mbyp)2(4,4-byp)2] (PF 6)4 (3), [Pd2(mbyp)2(t-pye) 2] (PF6)4 (4) [mbyp= 4,4-dimethyl-2,2- bipyridine, DPA= 1,2-bis(diphenylphosphino)acetylene, DPE= 1,2- bis(diphenylphosphino)ethylene, 4,4-byp= 4,4-bipyridine, and t-ype= trans 1,2-bis(4-pyridyl)ethylene)]. The catalytic activities of the new complexes have been investigated in the coupling of arylboronic acid derivatives to various olefins. Results obtained showed interesting catalytic activities and chemoselectivities for the new complexes in the coupling reactions to produce the conjugate addition and heck coupling products under free base or oxidant conditions.
- Suleiman, Rami,Shakil Hussain,Fettouhi, Mohammed,El Ali, Bassam
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scheme or table
p. 850 - 856
(2012/09/22)
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- Coupling reaction of magnesium alkylidene carbenoids with α-sulfonylallyllithiums: An efficient route to multi-substituted vinylallenes
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A variety of vinylallenes were successfully synthesized from 1-chlorovinyl p-tolyl sulfoxides and allyl or vinyl sulfones. Allyl and vinyl sulfones served as α-sulfonylallyllithium sources were prepared from carbonyl compounds in three or four steps in good overall yields. The coupling reaction of α-sulfonylallyllithiums with magnesium alkylidene carbenoids, which were generated from 1-chlorovinyl p-tolyl sulfoxides and isopropylmagnesium chloride, afforded multi-substituted vinylallenes in up to 88% yield. Georg Thieme Verlag KG Stuttgart · New York.
- Kimura, Tsutomu,Kobayashi, Gen,Ishigaki, Masashi,Inumaru, Mio,Sakurada, Jo,Satoh, Tsuyoshi
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p. 3623 - 3632
(2013/02/23)
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- A novel ketone olefination via organozinc reagents in the presence of diphenyl phosphite
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Carbonyl compounds react with organozinc reagents in the presence of diphenyl phosphite to give the corresponding olefins. A variety of 1,3-dienes and unsaturated esters were obtained in moderate to excellent yields under mild conditions. The Royal Society of Chemistry 2012.
- Cui, Hua,Li, Ying,Zhang, Songlin
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supporting information
p. 2862 - 2869
(2012/11/07)
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- Palladium-catalyzed desulfitative conjugate addition of aryl sulfinic acids and direct ESI-MS for mechanistic studies
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A new and efficient method for palladium(II) catalytic desulfitative conjugate addition of arylsulfinic acids with α,β-unsaturated carbonyl compound has been developed. The key reacting intermediates including aryl Pd(II) sulfinic intermediate, aryl Pd(II), and C=O-Pd complexes were captured by ESI-MS/MS, which provide new experimental evidence for the understanding of addition mechanism.
- Wang, Huifeng,Li, Yaming,Zhang, Rong,Jin, Kun,Zhao, Defeng,Duan, Chunying
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supporting information; experimental part
p. 4849 - 4853
(2012/07/02)
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- Pyridine ligands as promoters in PdII/0-catalyzed C-H olefination reactions
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Commercially available pyridine ligands can significantly enhance the rate, yield, substrate scope, and site selectivity of arene C-H olefination (Fujiwara-Moritani) reactions. The use of a 1:1 ratio of Pd/pyridine proved critical to maximize reaction rates and yields.
- Kubota, Asako,Emmert, Marion H.,Sanford, Melanie S.
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supporting information; experimental part
p. 1760 - 1763
(2012/05/20)
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