- Potassium hydride in paraffin: A useful base for organic synthesis
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The preparation of potassium hydride as a 1:1 homogenate with paraffin, termed KH(P), is reported. KH(P), a solid at room temperature, is stable without special handling. On suspension in THF with a phosphonium salt, KH(P) rapidly generates the ylide. Wit
- Taber, Douglass F.,Nelson, Christopher G.
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- Solvent role in the lipase-catalysed esterification of cinnamic acid and derivatives. Optimisation of the biotransformation conditions
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The esterification of cinnamic acid has been deeply investigated using ethanol as nucleophile and Candida antarctica lipase type B (CAL-B) as suitable biocatalyst. Special attention has been paid to the role that the solvent plays in the production of ethyl cinnamate. Therefore, volatile organic solvents and deep eutectic mixtures were employed in order to find optimal reaction conditions. Once that hexane was selected as the solvent of choice, other parameters that affect the enzyme activity were investigated in order to produce ethyl cinnamate with excellent yield. The CAL-B loading, nucleophile equivalents, temperature and reaction time have been identified as key parameters in the enzyme efficiency, and the potential of lipase-catalysed esterification has been finally exploited to produce a series of ethyl esters with different pattern substitutions on the aromatic ring.
- Suárez-Escobedo, Laura,Gotor-Fernández, Vicente
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- Electrochemical Generation of a Nonstabilized Azomethine Ylide: Access to Substituted N-Heterocycles
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Azomethine ylides are fascinating 1,3-dipoles for [3 + 2] cycloaddition reactions toward the construction ofN-heterocycles. Herein, an efficient and environmentally benign electrochemical approach for the generation of a nonstabilized azomethine ylide has been established under metal-free and external oxidant-free conditions. The resulting 1,3-dipole undergoes a [3 + 2] cycloaddition reaction with olefins. This electrosynthetic methodology indulges a straightforward and facile approach for the construction of substituted pyrrolidines.
- Kumar, Rakesh,Banerjee, Prabal
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p. 16104 - 16113
(2021/11/18)
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- Regio- And diastereoselective Pd-catalyzed aminochlorocyclization of allylic carbamates: scope, derivatization, and mechanism
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The regio- and diastereoselective synthesis of oxazolidinonesviaa Pd-catalyzed vicinal C-N/C-Cl bond-forming reaction from internal alkenes of allylic carbamates is reported. The oxazolidinones are obtained in yields of 44 to 95% with high to excellent diastereoselectivities (from 6?:?1 to >20?:?1 dr) from readily available precursors. This process is scalable, and the products are suitable for the synthesis of useful amino alcohols. A detailed theoretical and experimental mechanistic study was carried out to describe that the reaction proceeds through ananti-aminopalladation of the alkene followed by an oxidative C-Pd(ii) cleavage with retention of the carbon stereochemistry to yield the major diastereomer. The role of Cu(ii) in a C-Cl bond-forming mechanism step has also been proposed.
- Ariga, Elaine Miho,Carita Correra, Thiago,Matsushima, Jullyane Emi,McIndoe, J. Scott,Moreira Ribeiro, Francisco Wanderson,Omari, Isaac,Papa Spadafora, Bruna,Rodrigues, Alessandro,Soares, Priscila Machado Arruda,Vinhato, Elisangela,de Oliveira-Silva, Diogo
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supporting information
p. 5595 - 5606
(2021/07/02)
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- Selective Synthesis of Z-Cinnamyl Ethers and Cinnamyl Alcohols through Visible Light-Promoted Photocatalytic E to Z Isomerization
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A photocatalytic E to Z isomerization of alkenes using an iridium photosensitizer under mild reaction conditions is disclosed. This method provides scalable and efficient access to Z-cinnamyl ether and allylic alcohol derivatives in high yields with excellent stereoselectivity. Importantly, this method also provides a powerful strategy for the selective synthesis of Z-magnolol and honokiol derivatives possessing potential biological activity.
- Li, Hengchao,Chen, Hang,Zhou, Yang,Huang, Jin,Yi, Jundan,Zhao, Hongcai,Wang, Wei,Jing, Linhai
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supporting information
p. 555 - 559
(2020/02/05)
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- Intramolecular Povarov Reactions for the Synthesis of Chromenopyridine Fused 2-Pyridone Polyheterocycles Binding to α-Synuclein and Amyloid-β Fibrils
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A BF3·OEt2 catalyzed intramolecular Povarov reaction was used to synthesize 15 chromenopyridine fused thiazolino-2-pyridone peptidomimetics. The reaction works with several O-alkylated salicylaldehydes and amino functionalized thiazolino-2-pyridones, to generate polyheterocycles with diverse substitution. The synthesized compounds were screened for their ability to bind α-synuclein and amyloid β fibrils in vitro. Analogues substituted with a nitro group bind to mature amyloid fibrils, and the activity moreover depends on the positioning of this functional group.
- Adolfsson, Dan E.,Tyagi, Mohit,Singh, Pardeep,Deuschmann, Adrian,?dén, J?rgen,Gharibyan, Anna L.,Jayaweera, Sanduni Wasana,Lindgren, Anders E. G.,Olofsson, Anders,Almqvist, Fredrik
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supporting information
p. 14174 - 14189
(2020/11/13)
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- Metal-free domino Cloke-Wilson rearrangement-hydration-dimerization of cyclopropane carbaldehydes: A facile access to oxybis(2-aryltetrahydrofuran) derivatives
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In this work, we have demonstrated a metal-free transformation of cyclopropane carbaldehydes to oxybis(2-aryltetrahydrofuran) derivatives via a domino Cloke-Wilson rearrangement-hydration-dimerization sequence. Commercially inexpensive p-toluene sulfonic acid (PTSA) was used as a Br?nsted acid catalyst, and reactions were conducted in an open-flask. Detection of reaction intermediates were carried to get an insight into the reaction pathway.
- Banerjee, Prabal,Dey, Raghunath,Rajput, Shruti
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- Atomically precise palladium nanocluster catalyzed tandem oxidation processes of alcohols and phosphorous ylides: Facile access to α,β-unsaturated esters
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The mesoporous silica nanosphere supported palladium nanocluster was synthesized through a simple impregnation method and well characterized. The as prepared catalyst shows excellent catalytic performance in tandem oxidation process (TOP) of alcohol and phosphorous ylide, which provides an efficient access to α,β-unsaturated esters with high yields utilizes 1 atmosphere of molecular oxygen as sole oxidant. This work represents the first example of atomically precise palladium nanocluster catalyzed tandem oxidation process of alcohol and phosphorous ylide and is expected to open new horizons for nanoclusters in the tandem reactions.
- Gao, Taiping,Du, Jialei,Liu, Wenyan,Ren, Mingxia
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supporting information
(2020/09/17)
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- Asymmetric Synthesis of Cα-Substituted Prolines through Curtin–Hammett-Controlled Diastereoselective N-Alkylation
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Asymmetric synthesis of α-substituted proline derivatives has been accomplished by an efficient chirality-transfer method. High diastereoselectivity of the N-alkylation of the proline ester (C→N chirality transfer) was achieved when a 2,3-disubstituted be
- Cho, Hyunkyung,Jeon, Hongjun,Shin, Jae Eui,Lee, Seokwoo,Park, Soojun,Kim, Sanghee
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supporting information
p. 2447 - 2451
(2019/01/30)
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- Synthesis of Functionalized Indolines and Dihydrobenzofurans by Iron and Copper Catalyzed Aryl C-N and C-O Bond Formation
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A simple and effective one-pot, two-step intramolecular aryl C-N and C-O bond forming process for the preparation of a wide range of benzo-fused heterocyclic scaffolds using iron and copper catalysis is described. Activated aryl rings were subjected to a highly regioselective, iron(III) triflimide-catalyzed iodination, followed by a copper(I)-catalyzed intramolecular N-or O-arylation step leading to indolines, dihydrobenzofurans, and six-membered analogues. The general applicability and functional group tolerance of this method were exemplified by the total synthesis of the neolignan natural product, (+)-obtusafuran. DFT calculations using Fukui functions were also performed, providing a molecular orbital rationale for the highly regioselective arene iodination process.
- Henry, Martyn C.,Senn, Hans Martin,Sutherland, Andrew
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p. 346 - 364
(2019/01/08)
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- Copper-Catalyzed Perfluoroalkylation of Allyl Phosphates with Stable Perfluoroalkylzinc Reagents
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A general and practical method for copper-catalyzed cross-coupling of allyl phosphates with stable perfluoroalkylzinc reagents has been developed. The reaction proceeds under mild reaction conditions with high efficiency, good functional group tolerance, and high regio- A nd stereoselectivities and provides general, straightforward, and useful access to allyl-perfluoroalkyl compounds. Preliminary mechanistic studies reveal that the allyl copper intermediate may be involved in the catalytic cycle.
- Liu, Lihua,Bao, Xifei,Xiao, Hua,Li, Junlan,Ye, Feifan,Wang, Chaoqin,Cai, Qinhua,Fan, Shilu
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p. 423 - 434
(2019/01/08)
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- COMPOUNDS REDUCING MALODOUR PERCEPTION AND THE USE THEREOF
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The present invention relates to new malodour-counteracting agents of formula (I) or stereoisomers thereof, particularly useful in blocking the olfactory perception of androstenone, Formula (I), wherein R1, R2, R3,R4, R5, R6, R7 and X have the same meaning as that defined in the claims. The present invention also relates to consumer products comprising said agents. The present invention also relates to the use of said agents to suppress or attenuate undesirable odour, as well as to methods to suppress or attenuate undesirable odour employing said compounds.
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Page/Page column 53; 54
(2018/09/08)
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- Rh(III)-Catalyzed Enaminone-Directed C-H Coupling with α-Diazo-α-phosphonoacetate for Reactivity Discovery: Fluoride-Mediated Dephosphonation for C-C Coupling Reactions
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Rh(III)-catalyzed enaminone-directed C-H coupling with α-diazo-α-phosphonoacetate has been used for the identification of fluoride-mediated dephosphonation C-C coupling reactivity for the synthesis of 4-hydroxy-1-naphthoates. Intermolecular C-C coupling of α-phosphonoacetate and benzaldehyde for (E)-selective α,β-unsaturated ester synthesis has also been achieved.
- Song, Chao,Yang, Chen,Zeng, Hua,Zhang, Wenjing,Guo, Shan,Zhu, Jin
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supporting information
p. 3819 - 3823
(2018/07/22)
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- One-Pot Synthesis of α,β-Unsaturated Esters, Ketones, and Nitriles from Alcohols and Phosphonium Salts
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A general method for the synthesis of α,β-unsaturated esters, ketones, and nitriles is successfully achieved by a one-pot copper-catalyzed oxidation with O 2 in air as oxidant. The solvent mixture of acetonitrile and formamide (1:1) is optimized to ensure the oxidation of alcohols, deprotonation of phosphonium salt, and Wittig reaction occur efficiently in one pot. A broad range of substrates has been explored for this process, including three electron-withdrawing group (CO 2 Et, COPh, CN) functionalized phosphonium salts. They reacted not only with benzylic and heteroaromatic alcohols, but also with aliphatic alcohols, forming the corresponding α,β-unsaturated esters, ketones, and nitriles in moderate to excellent yields.
- Ding, Weijie,Hu, Juan,Jin, Huile,Yu, Xiaochun,Wang, Shun
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p. 107 - 118
(2017/09/28)
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- Facile synthesis of α, β-unsaturated esters through a one-pot copper-catalyzed aerobic oxidation-Wittig reaction
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An efficient one-pot synthesis of α, β-unsaturated esters through the aerobic oxidation – Wittig tandem reaction of alcohols and phosphorous ylide is developed. This new method operates under mild reaction conditions, and uses CuI/TEMPO (TEMPO = 2,2,6,6-tetramethylpiperidine-N-oxyl) as co-catalyst and air (O2) as the oxidant. It tolerates a wide range of functionalized benzylic alcohol and aliphatic alcohols.
- Ren, Cheng,Shi, Zhenyu,Ding, Weijie,Liu, Zhiqing,Jin, Huile,Yu, Xiaochun,Wang, Shun
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supporting information
p. 14 - 17
(2017/12/06)
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- Tandem Palladium and Isothiourea Relay Catalysis: Enantioselective Synthesis of α-Amino Acid Derivatives via Allylic Amination and [2,3]-Sigmatropic Rearrangement
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A tandem relay catalytic protocol using both Pd and isothiourea catalysis has been developed for the enantioselective synthesis of α-amino acid derivatives containing two stereogenic centers from readily accessible N,N-disubstituted glycine aryl esters and allylic phosphates. The optimized process uses a bench-stable succinimide-based Pd precatalyst (FurCat) to promote Pd-catalyzed allylic ammonium salt generation from the allylic phosphate and the glycine aryl ester. Subsequent in situ enantioselective [2,3]-sigmatropic rearrangement catalyzed by the isothiourea benzotetramisole forms syn-α-amino acid derivatives with high diastereo- and enantioselectivity. This methodology is most effective using 4-nitrophenylglycine esters and tolerates a variety of substituted cinnamic and styrenyl allylic ethyl phosphates. The use of challenging unsymmetrical N-allyl-N-methylglycine esters is also tolerated under the catalytic relay conditions without compromising stereoselectivity.
- Spoehrle, Stéphanie S. M.,West, Thomas H.,Taylor, James E.,Slawin, Alexandra M. Z.,Smith, Andrew D.
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supporting information
p. 11895 - 11902
(2017/09/07)
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- Bu 4 N + -Controlled Addition and Olefination with Ethyl 2-(Trimethylsilyl)acetate via Silicon Activation
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Catalytic Bu 4 NOAc as silicon activator of ethyl 2-(trimethylsilyl)acetate, in THF, was utilized for the synthesis of β-hydroxy esters, whereas employing catalytic Bu 4 NOTMS gave α,β-unsaturated esters. The established reaction conditions were applicable to a diverse range of aromatic, heteroaromatic, aliphatic aldehydes and ketones. Reactions were achieved at room temperature without taking any of the specialized precautions that are in place for other organometallics. A stepwise olefination pathway via silylated β-hydroxy esters with subsequent elimination to form the α,β-unsaturated ester has been demonstrated. The key to selective product formation lies in use of the weaker acetate activator which suppresses subsequent elimination whereas stronger TMSO - activator (and base) facilitates both addition and elimination steps. The use of tetrabutyl ammonium salts for both acetate and trimethylsilyloxide activators provide enhanced silicon activation when compared to their inorganic cation counterparts.
- Das, Manas,Manvar, Atul,Fox, Ian,Roberts, Dilwyn J.,O'Shea, Donal F.
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supporting information
p. 2401 - 2406
(2017/09/30)
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- Piperlongumine derived cyclic sulfonamides (sultams): Synthesis and in?vitro exploration for therapeutic potential against HeLa cancer cell lines
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A novel modification of piperlongumine is designed, bearing a cyclic sulphonamide (sultam) and its synthesis is described. For the first time herein we report the synthesis and biological evaluation of the natural product derived cyclic sulfonamides using Grubbs second generation catalyst (Grubbs II) via ring closing metathesis approach. Synthesis of a series of piperlongumine derived sultams is done in a moderate to good yield using Wittig reaction, Ring-Closing Metathesis (RCM) and, amide synthesis by using mixed anhydride, approach. All synthesized compounds were evaluated for anticancer activity and some demonstrated dose dependent reduction in HeLa cell growth. Of these 7, 10 and 14 significantly reduced the cell growth. Consequently their calculated GI50values were found to be 0.1 or 0.1?μM.
- Lad, Nitin P.,Kulkarni, Sarang,Sharma, Rajiv,Mascarenhas, Malcolm,Kulkarni, Mahesh R.,Pandit, Shivaji S.
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p. 870 - 878
(2016/12/18)
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- 5,6-dihydropyrrolo[2,1-a]isoquinolines as alternative of new drugs with cytotoxic activity
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In this study, the pyrrolo[2,1-a]isoquinolines 4a–n were synthesized in good yields in a three steps synthesis from the corresponding α,β-unsaturated esters starting materials. These compounds were tested on six human cancer cells lines to measure the cyt
- Chávez-Santos, Rosa María,Torres-Ochoa, Rubén Omar,Ramírez-Apan, María Teresa,Martínez, Roberto,Reyes-Gutiérrez, Paul Eduardo
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p. 973 - 981
(2018/11/02)
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- Silver-Catalyzed Cross-Olefination of Donor and Acceptor Diazo Compounds: Use of N-Nosylhydrazones as Diazo Surrogate
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The cross-olefination reaction of donor and acceptor diazo compounds was explored. The use of N-nosylhydrazones as diazo surrogates and the dependence on silver catalysis were crucial for the reaction development. A variety of (hetero)aryl N-nosylhydrazones and α-diazo esters, amides, and phosphonates were compatible, and the functionalized alkene products were afforded in good to high yields with moderate (Z)/(E) selectivities. The experimental and DFT calculation results suggest that the cross-selectivity is due to selective activation of the silver catalyst for donor diazo compounds.
- Liu, Zhaohong,Liu, Binbin,Zhao, Xue-Feng,Wu, Yan-Bo,Bi, Xihe
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supporting information
p. 928 - 932
(2017/02/15)
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- Oxidative ring-opening of ferrocenylcyclopropylamines to N-ferrocenylmethyl β-hydroxyamides
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The in situ reduction of ferrocenyl cyclopropylimines to the corresponding amines triggers a facile oxidative ring-opening to yield the formal four-electron oxidation products: N-ferrocenylmethyl β-hydroxyamides. This process is believed to proceed via generation of a ferrocinium ion in the presence of air, leading to facile formation of a distonic radical cation that is ultimately trapped by oxygen.
- Gee, Yi Sing,Goertz, Neils J. M.,Gardiner, Michael G.,Hyland, Christopher J. T.
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supporting information
p. 2498 - 2503
(2016/03/01)
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- N-heterocyclic carbene-catalysed Peterson olefination reaction
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N-heterocyclic carbenes (NHCs) have been utilised as highly efficient organocatalysts to catalyse Peterson olefination reaction of aldehydes with trimethylsilylketene ethyl trimethylsilyl acetal or fluoro(trimethylsilyl)ketene ethyl trimethylsilyl acetal to produce the corresponding functionalized olefines in 34-93% yields with excellent stereoselectivities.
- Wang, Ying,Du, Guang-Fen,Gu, Cheng-Zhi,Xing, Fen,Dai, Bin,He, Lin
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p. 472 - 478
(2015/12/31)
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- Design and synthesis of a series of serine derivatives as small molecule inhibitors of the SARS coronavirus 3CL protease
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Synthesis of serine derivatives having the essential functional groups for the inhibitor of SARS 3CL protease and evaluation of their inhibitory activities using SARS 3CL R188I mutant protease are described. The lead compounds, functionalized serine derivatives, were designed based on the tetrapeptide aldehyde and Bai's cinnamoly inhibitor, and additionally performed with simulation on GOLD softwear. Structure activity relationship studies of the candidate compounds were given reasonable inhibitors ent-3 and ent-7k against SARS 3CL R188I mutant protease. These inhibitors showed protease selectivity and no cytotoxicity.
- Konno, Hiroyuki,Wakabayashi, Masaki,Takanuma, Daiki,Saito, Yota,Akaji, Kenichi
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supporting information
p. 1241 - 1254
(2016/03/01)
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- Tandem oxidation–Wittig reaction using nanocrystalline barium manganate (BaMnO4); an improved one-pot protocol
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A one-pot, tandem oxidation–Wittig procedure has been developed in which the reacting components are generated in situ from alcohols, triphenyl phosphine, and ethyl bromoacetate using barium manganate as a mild oxidizing agent without the addition of an external base.
- Gholinejad, Mohammad,Firouzabadi, Habib,Bahrami, Maedeh,Nájera, Carmen
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supporting information
p. 3773 - 3775
(2016/07/26)
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- BF3·OEt2-mediated: Syn -selective Meyer-Schuster rearrangement of phenoxy propargyl alcohols for Z -β-aryl-α,β-unsaturated esters
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Synthesis of Z-β-aryl-α,β-unsaturated esters from readily available 1-aryl-3-phenoxy propargyl alcohols is achieved via a BF3-mediated syn-selective Meyer-Schuster rearrangement under ambient conditions. The reaction mechanism is postulated to involve an electrophilic borylation of an allene intermediate as the key step to kinetically control the stereoselectivity.
- Puri, Surendra,Hari Babu, Madala,Sridhar Reddy, Maddi
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p. 7001 - 7009
(2016/07/30)
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- Ligand-Free Heck Reactions of Aryl Iodides: Significant Acceleration of the Rate through Visible Light Irradiation at Ambient Temperature
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A mild Heck reaction of aryl iodides and olefins was realized by the cooperation of a palladium and a photoredox catalyst under the irradiation of visible light. This protocol works well to synthesize stilbenes with high Z/E ratios and (E)-cinnamates in the absence of ligands at ambient temperature. Control experiments revealed that palladium salt, visible light and photoredox catalyst were all crucial for the achievement of this cross-coupling under mild conditions. (Figure presented.).
- Zhang, Heng,Huang, Xueliang
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supporting information
p. 3736 - 3742
(2016/12/16)
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- Ethyl cinnamate derivatives as promising high-efficient acaricides against Psoroptes cuniculi: Synthesis, bioactivity and structure-activity relationship
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This paper reported the synthesis, structure-activity relationship (SAR) and acaricidal activity in vitro against Psoroptes cuniculi, a mange mite, of 25 ethyl cinnamate derivatives. All target compounds were synthesized and elucidated by means of MS, 1H- and 13C-NMR analysis. The results showed that 24 out of 25 tested compounds at 1.0 mg/mL demonstrated acaricidal activity in varying degrees. Among them, 6, 15, 26, 27 and 30 showed significant activity with median lethal concentration values (LC50) of 89.3, 119.0, 39.2, 29.8 and 41.2 μg/mL, respectively, which were 2.1- to 8.3-fold the activity of ivermectin (LC50=247.4 μg/mL), a standard drug in the treatment of Psoroptes cuniculi. Compared with ivermectin, with a median lethal time value (LT50) of 8.9 h, 27 and 30 showed smaller LTM50 values of 7.9 and 1.3 h, respectively, whereas 6, 15 and 26 showed slightly larger LT50 values of 10.6, 11.0 and 10.4 h at 4.5 μmol/mL. SARs showed that the presence of o-NO2 or m-NO2 on the benzene ring significantly improved the activity, whereas the introduction of a hydroxy, methoxy, acetoxy, methylenedioxy, bromo or chloro group reduced the activity. (E)-Cinnamates were more effective than their (Z)-isomer. Nevertheless, the carbon-carbon double bond in the acrylic ester moiety was proven not to be essential to improve the activity of cinnamic acid esters. Thus, the results strongly indicate that cinnamate derivatives, especially their dihydro derivatives, should be promising candidates or lead compounds for the development of novel acaricides for the effective control of animal or human acariasis.
- Zhang, Bingyu,Lv, Chao,Li, Weibo,Cui, Zhiming,Chen, Dongdong,Cao, Fangjun,Miao, Fang,Zhou, Le
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p. 255 - 262
(2015/04/22)
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- Divergent Gold(I)-Catalyzed Skeletal Rearrangements of 1,7-Enynes
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The gold(I) complex catalyzed cycloisomerization and skeletal rearrangement of 1,n-enynes (n=5-7) is a powerful methodology for the efficient synthesis of complex molecular architectures. In contrast to 1,6-enynes, readily accessible homologous 1,7-enynes are largely unexplored in such transformations. Here, the divergent skeletal rearrangement of all-carbon 1,7-enynes by catalysis with a cationic gold(I) complex is reported. Depending on electronic and steric factors, differently substituted 1,7-enynes react via different carbocations formed from a common gold carbene intermediate to yield on the one hand novel exocyclic allenes and on the other hand tricyclic hexahydro-anthracenes through a novel dehydrogenative Diels-Alder reaction. Two birds with a gold-stone! Divergent gold(I) catalysis unraveled a novel cycloisomerization and a dehydrogenative Diels-Alder reaction of 1,7-enynes.
- Mei?, Rebecca,Kumar, Kamal,Waldmann, Herbert
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supporting information
p. 13526 - 13530
(2015/09/22)
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- Dialkylzinc-mediated allylic polyfluoroarylation reaction
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Abstract We present an allylic polyfluoroarylation reaction with broad substrate scope and excellent functional group tolerance, using organozinc reagents under mild conditions. A catalytic amount of triphenylphosphine oxide efficiently promotes iodine-zinc exchange reaction between polyfluoroaryl iodide and dimethylzinc, and the resulting phosphine oxide-activated polyfluoroarylzinc undergoes substitution reaction with allylic halides to afford the corresponding polyfluoroarylated products.
- Kurauchi, Daisuke,Hirano, Keiichi,Kato, Hisano,Saito, Tatsuo,Miyamoto, Kazunori,Uchiyama, Masanobu
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supporting information
p. 5849 - 5857
(2015/08/03)
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- Silylative cyclopropanation of allyl phosphates with silylboronates
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A potassium-bis(trimethylsilyl)amide-mediated cyclopropanation of allyl phosphates with silylboronates has been developed. Unlike the reported copper-catalyzed allylic substitution reactions, the nucleophile selectively attacks at the β-position of the allylic substrates under the present reaction conditions. The mechanism of this process has also been investigated, thus indicating the involvement of a silylpotassium species as the active nucleophilic component.
- Shintani, Ryo,Fujie, Ryuhei,Takeda, Momotaro,Nozaki, Kyoko
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supporting information
p. 6546 - 6549
(2014/06/24)
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- Aza-Bellus-Claisen rearrangement-enabled synthesis of racemic tapentadol and its stereoisomers
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A concise synthesis of racemic Tapentadol and its stereoisomers was presented. The key step was a TiCl4·THF2-catalzyed aza-Bellus-Claisen rearrangement to create two vicinal tertiary carbon stereogenic centers. The subsequent reducti
- Bai, Donghu,Huang, Sha-Hua,Lin, Zuming,Yang, Lin,Dai, Junzeng,Huang, Meng-Yuan,Jia, Xueshun,Hong, Ran
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supporting information
p. 317 - 320
(2013/08/22)
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- Catalytic enantioselective dibromination of allylic alcohols
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A new dibromination reaction involving the combination of dibromomalonate as the bromonium source and a titanium bromide species as the bromide source has been developed. Enantioselective catalysis has been achieved through apparent ligand acceleration by a tartaric acid-derived diol.
- Hu, Dennis X.,Shibuya, Grant M.,Burns, Noah Z.
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supporting information
p. 12960 - 12963
(2013/09/24)
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- Palladium-catalyzed Mizoroki-Heck type reaction with aryliodine diacetates using hydrazone ligand
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We developed a palladium-catalyzed Mizoroki-Heck type reaction of olefins with such hypervalent iodine reagents as iodobenzene diacetate in good to high yields using 2 mol% of a heterocyclic hydrazone (1b)-Pd(OAc)2 system in NMP under air at 90 °C. The Japan Institute of Heterocyclic Chemistry.
- Mino, Takashi,Watanabe, Kohei,Abe, Taichi,Kogure, Taketo,Sakamoto, Masami
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p. 2015 - 2021
(2013/10/22)
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- Synthesis of a novel 8-hydroxyquinoline functionalized poly (ethylene glycol) bridged dicationic ionic liquid and its application in palladium-catalyzed Heck reaction under solvent-free conditions
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A novel 8-hydroxyquinoline functionalized poly (ethylene glycol) bridged dicationic ionic liquid ([HQ-PEG1000-DIL][BF4]) was synthesized and characterized. It was applied as an efficiently recyclable ligand for Pd-catalyzed Heck reaction under solvent-free conditions. It is noteworthy that the Pd(OAc)2/[HQ-PEG1000-DIL][BF 4] catalytic system could be easily recovered and reused without obvious loss of catalytic activity after five recycling runs.
- Wang, Yinglei,Luo, Jun,Liu, Zuliang
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- Solid supported palladium(0) nano/microparticle: A ligand-free efficient recyclable heterogeneous catalyst for mono- and β,β-double-Heck reaction
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Solid supported palladium nano/microparticles were found to be active catalysts to perform mono- and β,β-double-Heck reactions. Different β-unsubstituted and substituted alkenes including acrylate, methacrylate, crotonate, styrene, acrylonitrile, and acrylamide were investigated successfully for mono- and β,β-double-Heck reactions with aryl iodide under milder reaction condition. One-pot β,β-double-Heck reaction of aryl iodides with α,β-unsaturated ester, amide, nitrile, and styrene derivatives were also performed under standard reaction conditions. Wide functional group tolerance, easy catalyst recovery, and recyclability up to twelve times without significant loss of catalytic activity added extra importance to the present process.
- Sharma, Dharminder,Kumar, Sandeep,Shil, Arun K.,Guha, Nitul Ranjan,Bandna,Das, Pralay
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supporting information
p. 7044 - 7051
(2013/01/15)
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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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- An efficient and general method for the heck and buchwald-hartwig coupling reactions of aryl chlorides
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The β-diketiminatophosphane Pd complex acted as a powerful catalyst for the Heck coupling of aryl chlorides with alkenes. Various aryl and heteroaryl chlorides were coupled efficiently under relatively mild conditions. Furthermore, this catalytic system also proved to be highly active in the Buchwald-Hartwig coupling of deactivated and sterically hindered aryl chlorides at room temperature.
- Lee, Dong-Hwan,Taher, Abu,Hossain, Shahin,Jin, Myung-Jong
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supporting information; experimental part
p. 5540 - 5543
(2011/12/15)
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- Effect of phase transfer chemistry, segmented fluid flow, and sonication on the synthesis of cinnamic esters
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Wittig reaction under Phase Transfer conditions was performed in a flow reaction system. Different bases, aldehydes, phosphonium salts, and flow reaction parameters were investigated, in absence of a phase transfert catalyst. An improvement of the reaction outcome (yield and reaction time) was achieved through the immersion of the reactor into an ultrasound bath.
- Riccaboni, Mauro,La Porta, Elena,Martorana, Andrea,Attanasio, Roberta
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experimental part
p. 4032 - 4039
(2010/07/06)
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- P[N(i-Bu)CH2CH2]3N: Nonionic Lewis base for promoting the room-temperature synthesis of α,β-unsaturated esters, fluorides, ketones, and nitriles using Wadsworth - Emmons phosphonates
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The bicyclic triaminophosphine P(RNCH2CH2) 3N (R = i-Bu, 1c) serves as an effective promoter for the room-temperature stereoselective synthesis of α,β-unsaturated esters, fluorides, and nitriles from a wide array of aromatic, aliphatic, heterocyclic, and cyclic aldehydes and ketones, using a range of Wadsworth-Emmons (WE) phosphonates. Among the analogues of 1c [R = Me (1a), i-Pr (1b), Bn (1d)], 1a and 1b performed well, although longer reaction times were involved, and 1d led to poorer yields than 1c. Functionalities such as cyano, chloro, bromo, methoxy, amino, ester, and nitro were well tolerated. We were able to isolate and characterize (by X-ray means; see above) the reactive WE intermediate species formed from 2b and 1c.
- Chintareddy, Venkat Reddy,Ellern, Arkady,Verkade, John G.
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supporting information; experimental part
p. 7166 - 7174
(2010/12/25)
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- Expedient access to branched allylic silanes by copper-catalysed allylic substitution of linear allylic halides
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An unprecedented copper-catalysed allylic transposition enables the regioselective synthesis of branched allylic silanes from linear allylic halides through direct C-Si bond formation.
- Vyas, Devendra J.,Oestreich, Martin
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supporting information; experimental part
p. 568 - 570
(2010/05/01)
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- Pd-porphyrin functionalized ionic liquid-modified mesoporous SBA-15: An efficient and recyclable catalyst for solvent-free Heck reaction
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The Pd-porphyrin functionalized ionic liquid could be covalently anchored in the channels of mesoporous SBA-15 through ion-pair electrostatic interaction between imidazolium-cationic and Pd-porphyrin-anionic moieties. Such modified SBA-15 materials were prepared successfully via a post-synthesis (surface sol-gel polymerization) or a one-pot sol-gel procedure, which were characterized by powder X-ray diffraction, UV-visible spectroscopy, Fourier transform infrared spectroscopy, N2 sorption, elemental analysis, and transmission electron microscopy. The modified SBA-15 materials are efficient and recyclable catalysts for cross-coupling of aryl iodides or activated aryl bromides with ethyl acrylate without activity loss and Pd leaching even after 9 runs.
- Zhang, Jing,Zhao, Guo-Feng,Popovi?, Zora,Lu, Yong,Liu, Ye
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experimental part
p. 1648 - 1653
(2011/01/11)
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- TETRAHYDROBENZOTHIOPHENE DERIVATIVES
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Compounds of a certain formula I, in which Ra and Rb have the meanings indicated in the description, are novel effective compounds with anti-proliferative and apoptosis inducing activity.
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Page/Page column 188
(2008/06/13)
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- Novel Tetrahydropyridothiophenes
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Compounds of a certain formula (I) in which Ra and Rb have the meanings indicated in the description, are novel effective compounds with anti-proliferative and apoptosis inducing activity.
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Page/Page column 64
(2008/12/04)
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- Synthesis of catechins via thiourea/AuCl3-catalyzed cycloalkylation of aryl epoxides
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(Chemical Equation Presented) A diversity-oriented approach for the synthesis of structurally diverse catechins was achieved in good yields via thiourea/AuCl3/AgOTf-catalyzed annulations of aryl epoxides under mild conditions. This new protocol provides a highly efficient entry to a library of catechins-derived natural products, notably anti-HIV agent 8-C-ascorbyl-(-)-epigallocatechin.
- Liu, Yongxiang,Li, Xiben,Lin, Guang,Xiang, Zheng,Xiang, Jing,Zhao, Mingzhe,Chen, Jiahua,Yang, Zhen
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p. 4625 - 4629
(2008/09/20)
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- Sodium 2-(2-pyridin-3-ylethylamino)sulfonate: an efficient ligand and base for palladium-catalyzed Heck reaction in aqueous media
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The first successful Pd(OAc)2, N-donor ligand and base mediated Heck coupling reaction of aryl halides and alkenes in water is described. The corresponding Heck products were obtained in good to excellent yields.
- Pawar, Shivaji S.,Dekhane, Deepak V.,Shingare, Murlidhar S.,Thore, Shivaji N.
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p. 4252 - 4255
(2008/09/21)
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- Stereoselective synthesis of the C31-C39 unit of (+)-phorboxazoles from m-anisaldehyde
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A stereoselective route for the synthesis of the C31-C39 fragment of (+)-phorboxazoles is described. The route features Birch reduction, ozonolysis and acid-catalysed cyclisation of enantiopure precursors as key transformations to give the tetrahydropyran
- Kumar, S. Praveen,Nagaiah
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p. 1391 - 1394
(2007/10/03)
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- A highly stereoselective TMSOTf-mediated catalytic carbocupration of alkynoates
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(Chemical Equation Presented) The TMSOTf-mediated catalytic carbocupration of ynoates has been investigated. It has been shown that catalyst loadings as low as 5 mol % readily allow for high yields and diastereosetectivities for a series of aromatic Grignard reagents. In addition, we have been successful in vicinally functionalizing 1a via initial TMSOTf-mediated catalytic carbocupration followed by a secondary electrophilic capture of the TMS allenoate intermediate.
- Mueller, Amanda J.,Jennings, Michael P.
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p. 5327 - 5329
(2008/09/17)
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- The photochemistry of ring-substituted cinnamyl acetates
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The photochemistry of the (E)-cinnamyl acetates ((E)-1-aryl-3-propenyl acetates, 8a-8e) with substituents H, 4-CH3O, 3-CH3O, 4-CF3, and 3-CF3, respectively, was examined in both cyclohexane and methanol solvents. Alkene isomerization (E to Z) occurred more efficiently than other reactions and evidence is presented that this process occurs from the excited triplet state. In a slower process, 1,3-migration of the acetoxy group led to the rearranged 3-aryl-3-propenyl acetate isomers (9a-9e) as the major pathway, particularly in cylohexane. In methanol, the isomeric ethers 3-aryl-3-methoxypropene (14) and 1-aryl-3-methoxypropene (15) were formed by reaction of methanol with the photochemically generated cation. The combined yield of 14 and 15 (95% and 5%, respectively) was quantitative for the 4-methoxyphenyl compound (8b). Independent irradiations of the isomers 9a-9c demonstrated that the ethers 14 and 15 were primary photoproducts from 8 and not secondary photoproducts from 9. Fluorescence quantum yields and excited singlet state lifetimes indicated that the reactions, other than the E to Z isomerization, are from the excited singlet state.
- Fleming,Renault,Grundy,Pincock
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p. 1146 - 1154
(2007/10/03)
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- Arenediazonium o-benzenedisulfonimides as efficient reagents for Heck-type arylation reactions
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Arenediazonium o-benzenedisulfonimides can be used as new and efficient reagents for Heck-type arylation reactions of some common substrates containing C-C multiple bonds, namely ethyl acrylate, acrylic acid, acroleyne, styrene and cyclopentene. The reactions were carried out in an organic solvent, in the presence of Pd(OAc)2 as pre-catalyst, and gave rise to arylated products, for example, ethyl cinnamates, cinnamic acids, cinnamic aldehydes and stilbenes, possessing an (E)-configuration, and 1-arylcyclopentenes, in good to excellent yields. It is noteworthy that all the reactions led to the recovery, in greater than 80% yield, of o-benzenedisulfonimide, recyclable for the preparation of other diazonium salts.
- Artuso, Emma,Barbero, Margherita,Degani, Iacopo,Dughera, Stefano,Fochi, Rita
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p. 3146 - 3157
(2007/10/03)
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- Cycloalkyl alkanoic acids as integrin receptor antagonists derivatives
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The present invention relates to a class of compounds represented by the Formula I or a pharmaceutically acceptable salt thereof, pharmaceutical compositions comprising compounds of the Formula I, and methods of selectively inhibiting or antagonizing the αvβ3 and/or αvβ5 integrin.
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