- Rh(iii)-catalyzed diastereoselective cascade annulation of enone-tethered cyclohexadienonesviaC(sp2)-H bond activation
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Herein, we report highly diastereoselective arylative cyclization of enone-tethered cyclohexadienonesviaRh(iii)-catalyzed C-H activation ofN-methoxybenzamides. This reaction proceeds through the formation of a five-membered rhodacycle followed by bis-Michael cascade annulation to access functionalized bicyclic scaffolds with four contiguous stereocenters with a broad substrate scope. These products have excellent functional handles, allowing further synthetic transformation to increase the structural complexity. Furthermore, mechanistic studies of arylative cyclization and a gram-scale experiment are also presented.
- Chegondi, Rambabu,Jadhav, Sandip B.,Maurya, Sundaram,Navaneetha, N.
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supporting information
p. 13598 - 13601
(2021/12/23)
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- The Influence of Substitution on Thiol-Induced Oxanorbornadiene Fragmentation
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Oxanorbornadienes (ONDs) undergo facile Michael addition with thiols and then fragment by a retro-Diels-Alder (rDA) reaction, a unique two-step sequence among electrophilic cleavable linkages. The rDA reaction rate was explored as a function of the furan
- De Pascalis, Lucrezia,Yau, Mei-Kwan,Svatunek, Dennis,Tan, Zhuoting,Tekkam, Srinivas,Houk,Finn
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supporting information
p. 3751 - 3754
(2021/05/10)
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- Copper-Catalyzed N-O Cleavage of α,β-Unsaturated Ketoxime Acetates toward Structurally Diverse Pyridines
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The copper-catalyzed [4 + 2] annulation of α,β-unsaturated ketoxime acetates with 1,3-dicarbonyl compounds for the synthesis of three classes of structurally diverse pyridines has been developed. This method employs 1,3-dicarbonyl compounds as C2 synthons and enables the synthesis of multifunctionalized pyridines with diverse electron-withdrawing groups in moderate to good yields. The mechanistic investigation suggests that the reactions proceed through an ionic pathway.
- Ding, Xiaojuan,Duan, Jindian,Fang, Zheng,Guo, Kai,Li, Zhenjiang,Mao, Yiyang,Rong, Binsen,Xu, Gaochen,Zhang, Lei,Zhu, Ning
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supporting information
p. 2532 - 2542
(2020/03/13)
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- Catalyst-free green synthesis and study of antioxidant activity of new pyrazole derivatives
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In this research, a novel procedure for the synthesis of pyrazole derivatives in excellent yields was studied using catalyst-free multicomponent reaction of isoquinoline, activated acetylenic compounds, alkyl bromides, triphenylphosphine and hydrazine in
- Tabarsaei, Navisa,Hamedani, Naghmeh Faal,Shafiee, Shahin,Khandan, Samira,Hossaini, Zinatossadat
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p. 2945 - 2954
(2020/05/06)
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- Organocatalytic Enantioselective Selenosulfonylation of a C-C Double Bond to Form Two Stereogenic Centers in an Aqueous Medium
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Organocatalytic selenosulfonylation of the C-C double bond of α,β-unsaturated ketones to construct two contiguous stereogenic centers in an aqueous medium was described. A series of α-selenyl and β-sulfonyl ketones with various functional groups were synthesized in good yields and enantioselectivities with saturated NaCl solution as the solvent. In addition, this protocol had been successfully scaled up to a decagram scale via a simple workup procedure.
- Chen, Zhili,Hu, Fangli,Huang, Shengli,Zhao, Zhengxing,Mao, Hui,Qin, Wenling
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p. 8100 - 8111
(2019/06/17)
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- A Ba/Pd Catalytic System Enables Dehydrative Cross-Coupling and Excellent E-Selective Wittig Reactions
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A Ba/Pd cooperative catalysis system was developed to enable the dehydrative cross-coupling of allylic alcohols with P-ylides to occur directly and promote a subsequent Wittig reaction in one pot. A variety of multisubstituted 1,4-dienes were isolated in good to excellent yields with broad P-ylides (stabilized by both ester and ketone carbonyl groups) and aldehyde (aliphatic and aromatic) substrates with excellent E selectivity.
- Xie, Peizhong,Fu, Weishan,Cai, Xinying,Sun, Zuolian,Wu, Ying,Li, Shuangshuang,Gao, Cuiqing,Yang, Xiaobo,Loh, Teck-Peng
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supporting information
p. 7055 - 7059
(2019/09/12)
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- Tandem Wittig Reaction-Ring Contraction of Cyclobutanes: A Route to Functionalized Cyclopropanecarbaldehydes
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An original tandem reaction consisting of a Wittig reaction-ring contraction process between α-hydroxycyclobutanone and phosphonium ylides has been developed. Highly functionalized cyclopropanecarbaldehydes are obtained in good to high yield.
- Aitken, David J.,Caboni, Pierluigi,Cuccu, Federico,Frongia, Angelo,Luridiana, Alberto,Secci, Francesco,Serusi, Lorenzo
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supporting information
(2019/10/08)
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- Nonenzymatic Dynamic Kinetic Resolution of in situ Generated Hemithioacetals: Access to 1,3-Disubstituted Phthalans
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The first nonenzymatic DKR reaction of hemithioacetals is developed. Hemithioacetals were formed in situ via thiol addition and subsequently underwent an intramolecular oxa-Michael reaction. The scope of the reaction was quite broad ranging from aliphatic to aromatic substituents and 1,3-disubstituted-1,3-dihyroisobenzofuran products were obtained in good yields with moderate diastereoselectivities and high enantioselectivities. (Figure presented.).
- Nath, Utpal,Chowdhury, Deepan,Pan, Subhas Chandra
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supporting information
p. 1628 - 1633
(2018/03/21)
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- Novel hybrids derived from aspirin and chalcones potently suppress colorectal cancer in vitro and in vivo
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Colorectal cancer (CRC) remains the fourth leading cause of cancer deaths around the world despite the availability of many approved small molecules for treatment. The issues lie in the potency, selectivity and targeting of these compounds. Therefore, new
- Lu, Shan,Obianom, Obinna N.,Ai, Yong
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p. 1722 - 1732
(2018/10/26)
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- Synthesis of trifluoromethyl-/cyclopropyl-substituted 2-isoxazolines by DBU-promoted domino reaction
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NTrifluoromethyl and cyclopropyl substituted 2-isoxazolines were synthesized via a DBU-promoted domino reaction of β-trifluoromethyl-/β-cyclopropyl-substituted enones with hydroxylamine. The domino reaction consists of a Michael addition and the followed cyclization. A wide range of 3-substituted 5-cyclopropyl-5- trifluoromethyl-2-isoxazolines were obtained in good to excellent yields under mild reaction conditions. The method could also apply to other trifluoromethyl-substituted enones.
- Liu, Xiao-Dong,Ma, Hai-Yan,Xing, Chun-Hui,Lu, Long
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p. 1780 - 1783
(2017/07/27)
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- Enantioselective Organocatalytic Cascade Approach to Different Classes of Benzofused Acetals
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A novel enantioselective organocatalytic strategy is presented for the synthesis of tetrahydrofurobenzofuran and methanobenzodioxepine natural product core structures. The strategy is based on a pair of divergent reaction pathways in which hydroxyarenes react with γ-keto-α,β-unsaturated aldehydes, catalyzed by a chiral secondary amine. One reaction pathway, which leads to chiral 5,5-fused acetals with two stereocenters—the tetrahydrofurobenzofuran scaffolds—proceeds in moderate yields and up to 96 % ee. The other reaction pathway provides 5,6-bridged methanobenzodioxepine scaffolds with three stereocenters in moderate to good yields and up to 95 % ee. The reaction is remarkable as it can proceed with catalyst loadings as low as 0.25 mol %, providing one of the highest known turnover numbers in iminium ion catalysis. Furthermore, the hemiacetal tetrahydrofurobenzofuran can undergo functionalizations including reduction, oxidation, and allylation. Finally, the effects involved in the substrate control for the divergent pathways, based on both experimental and computational studies, have been investigated. A model involving steric, electronic and stereoelectronic interactions is discussed to rationalize the observed selectivities.
- Paz, Bruno Matos,Klier, Lydia,N?sborg, Line,Lauridsen, Vibeke Henriette,Jensen, Frank,J?rgensen, Karl Anker
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supporting information
p. 16810 - 16818
(2016/11/16)
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- Identification of novel chromenone derivatives as interleukin-5 inhibitors
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A series of (E)-5-alkoxy-3-(3-phenyl-3-oxoprop-1-enyl)-4H-chromen-4-ones (4) and (E)-5-alkoxy-3-(3-hydroxy-3-phenylprop-1-enyl)-4H-chromen-4-ones (5) were synthesized and evaluated for their IL-5 inhibitory activity. Propenone analogs 4 possess some of the structurally important characteristics of isoflavone 2 and chalcone 3 previously known as potent IL-5 inhibitor. However, the inhibitory activity of 4 was weak and therefore this structural hybridization appears to be ineffective for the design of IL-5 inhibitor. Meanwhile the potent activity profile of compounds 5 was discovered. This enhanced activity of 5 compared to 4 could be due to the effective location of hydroxyl group of allylic alcohol moiety of 5 in the 3D structure. The electron withdrawing substituents at position 4 of phenyl ring of 5 enhances the activity possibly due to an increase in the strength of hydrogen bonding property of hydroxyl group of allylic alcohol moiety.
- Venkateswararao, Eeda,Kim, Min-Seok,Sharma, Vinay K.,Lee, Ki-Cheul,Subramanian, Santhosh,Roh, Eunmiri,Kim, Youngsoo,Jung, Sang-Hun
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- Isothiourea-mediated one-pot synthesis of functionalized pyridines
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Acids to bases: The synthesis of 2,4,6-trisubstituted pyridines from (phenylthio)acetic acid and a range of α,β-unsaturated ketimines is reported. This process proceeds by intermolecular Michael addition/ lactamization, thiophenol elimination, and N- to O
- Stark, Daniel G.,Morrill, Louis C.,Yeh, Pei-Pei,Slawin, Alexandra M. Z.,O'Riordan, Timothy J. C.,Smith, Andrew D.
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supporting information
p. 11642 - 11646
(2013/11/06)
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- Edge-Shared [M2Cl10]2- complexes of reaction between oxophilic group 4 metal and phosphorus ylides1
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The reactions between oxophilic group 4 metal chlorides, α-keto ylides in THF, led to the forma-tion of titanium, zirconium and hafnium edge-shared [M2Cl10]2- complexes (1a-3f). We describe that the reaction between MClsu
- Sabounchei,Ahmadi,Shahriari,Hoseini-Fashami,Samiee
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experimental part
p. 1005 - 1013
(2012/10/08)
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- Edge-shared [M2Cl10]2-Complexes of reaction between oxophilic group IV metal and phosphorus ylides
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The reactions between oxophilic group 4 metal chlorides, a-keto ylides in THF, led to the formation of titanium, zirconium and hafnium edge-shared [M 2Cl10]2- complexes (1a-3d). With adding dimethyl sulfoxide as a ligand t
- Sabounchei, Seyyed Javad,Ahmadi, Mohsen,Shahriary, Parisa
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scheme or table
p. 1333 - 1337
(2012/09/07)
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- Stereoselective olefination of N-sulfonyl imines with stabilized phosphonium ylides for the synthesis of electron-deficient alkenes
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An unprecedented protocol has been developed for thestereoselective synthesis of structurally diverse electron-deficient alkenes in moderate to excellent yields from readily accessible N-sulfonyl imines and stabilized phosphonium ylides. Significantly, the olefination reaction of N-sulfonylimines with nitrile-stabilized phosphonium ylides affords an array of α,β-unsaturated nitriles with high Z selectivity, and the reactions with ester-, amide-, and ketone-stabilized phosphonium ylides afford α,β-unsaturated esters, amides, and ketones with high E selectivity, respectively. Spectroscopic analysis of the reaction mixtures and trapping of the intermediates allow plausible mechanisms to be proposed. Initialimine/ylide addition leads to the formation of betaines that cyclize to form 1,2-azaphosphetanes that subsequently eliminate iminophosphoranes to yield alkenes. For the synthesis of electron-deficient 1,2-disubstituted alkenes, the presence of an electron-withdrawing group in the betaine allows rapid interconversion between its two diastereomers through proton transfer. The Z/E selectivity for alkene synthesis is determined by the different rates at which the two betaine diastereomers form the corresponding 1,2-azaphosphetane diastereomers. In contrast, the Z/E selectivity for the synthesis of electron-deficient trisubstituted alkenes originates from the diastereoselective addition of stabilized phosphonium ylides to N-sulfonyl imines.
- Fang, Fan,Li, Yuan,Tian, Shi-Kai
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supporting information; experimental part
p. 1084 - 1091
(2011/04/15)
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- Crossed intramolecular rauhut-currier-type reactions via dienamine activation
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The intramolecular Rauhut-Currier reaction creates a carbon-carbon bond between two tethered Michael acceptors. Previous asymmetric versions have relied on 1,4-additions of chiral nucleophilic catalysts. Herein, we Investigate a novel strategy that involves the formation of electron rich dienamines as key Intermediates. Our methodology provides an efficient entry to the iridoid framework.
- Marques-Lopez, Eugenia,Herrera, Raquel P.,Marks, Timo,Jacobs, Wiebke C.,Koenning, Daniel,De Figueiredo, Renata M.,Christmann, Mathias
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supporting information; experimental part
p. 4116 - 4119
(2009/12/06)
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- New access to trisubstitutea 3-pyrrolines under phosphine catalysis
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Conjugated dienes, properly activated by electron-withdrawing groups on both ends, are shown to be suitable substrates for phosphinepromoted organocatalytic processes. Their reactions with imines, under phosphine catalysis, afford a new and efficient synthetic approach to functionalized 3-pyrrolines.
- Schuler, Marie,Duvvuru, Deepti,Retailleau, Pascal,Betzer, Jean-Francois,Marinetti, Angela
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supporting information; scheme or table
p. 4406 - 4409
(2009/12/26)
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- New mono and binuclear mercury(II) complexes of phosphorus ylides containing DMSO as ligand: Spectral and structural characterization
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Reaction of phosphorus ylides Ph3PCHC(O)C6H4NO2 (Y′) and (p-tolyl)3PCHC(O)C6H4Cl (Y″) with HgX2 (X = Cl, Br and I) in equimolar ratios using methanol as solvent leads
- Sabounchei, Seyyed Javad,Nemattalab, Hassan,Salehzadeh, Sadegh,Bayat, Mehdi,Khavasi, Hamid Reza,Adams, Harry
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p. 1975 - 1985
(2008/09/19)
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- Synthesis and characterization of new nitrate-bridged polymeric complexes of mercury(II) with phosphorus ylides
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Reaction of phosphorus ylides of the type X-C6H4-COCH{double bond, long}PAr3 (X = Cl and NO2; Ar = phenyl and p-tolyl) with Hg(NO3)2 · H2O in equimolar ratios using methanol as s
- Sabounchei, Seyyed Javad,Nemattalab, Hassan,Khavasi, Hamid Reza
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p. 5440 - 5446
(2008/03/12)
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- Synthesis, thermal reactivity and kinetics of substituted [(benzoyl)(phenylcarbamoyl)methylene]triphenylphosphoranes and their thiocarbamoyl analogues
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A range of 16 substituted benzoyl/arylcarbamoyl and benzoyl/ arylthiocarbamoyl stabilised ylides have been prepared. They are found under conditions of flash vacuum pyrolysis to fragment giving a benzoyl ylide and aryl isocyanate or isothiocyanate accompanied in some cases by secondary pyrolysis products. Kinetic studies show the thiocarbamoyl ylides to react consistently faster than their carbamoyl analogues and substituent effects suggest a polar cyclic transition state, which involves attack by the benzoyl oxygen on the carbamoyl/thiocarbamoyl NH. Graphical Abstract.
- Aitken, R. Alan,Al-Awadi, Nouria A.,Dawson, Graham,El-Dusouqi, Osman M.E.,Farrell, Dorcas M.M.,Kaul, Kamini,Kumar, Ajith
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p. 129 - 135
(2007/10/03)
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- Formation Reactions of Phosphorus Ylide-Tetracyanoquinodimethane Complexes
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The complexation reactions of tetracyanoquinodimethane (TCNQ) with phosphorus ylides have been studied.The binding energy is related to the electron density on the ylide atom as controlled by substituents.The degree of charge-transfer in the complex is also controlled by the substituents.The rate of formation of ylide-TCNQ complexes is slow enough to be measured, and a correlation between the reaction rate and the basicity of the ylide atoms was also established.
- Tsuchiya, Shinji,Mitomo, Shun-ichi,Kise, Hideo,Seno, Manabu
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p. 245 - 248
(2007/10/02)
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