- Active Base Hybrid Organosilica Materials based on Pyrrolidine Builder Units for Fine Chemicals Production
-
The catalytic activity of “pyrrolidine type” fragments included or anchored in the mesoporous silica supports or polymeric frameworks have been fully reported for enantioselective transformation. Nevertheless, low attention was focused on their catalytic abilities to perform base-catalyzed reaction. Accordingly, hybrid materials including pyrrolidine fragments in the mesoporous silica supports were prepared following different synthesis methods, such as micellar and fluoride sol-gel routes in absence of structural directing agents. Their great catalytic performance was explored for various base-catalyzed reactions to the formation of C?C bond through Knoevenagel, Claisen-Schmidt and Henry condensations under microwave irradiation. The benefits of microwave irradiation combined with suitable catalytic properties of pyrrolidine hybrid materials with strong base sites and high accessibility to active centers, allowed carrying out successfully base-catalyzed condensation reactions for the production of fine chemicals. Moreover, the hybrid catalyst exhibited high selectivity and good stability over different catalytic cycles contributing to environmental sustainability.
- Llopis, Sebastián,Velty, Alexandra,Díaz, Urbano
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p. 5012 - 5024
(2021/10/19)
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- Skeletally Tunable Seven-Membered-Ring Fused Pyrroles
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We describe a copper-mediated method that enables the synthesis of seven-membered-ring fused pyrroles (7-mrFPs). The protocol proceeds via an in situ spiro-intermediate ring expansion and tolerates a library of 7-mrFP derivatives with a broad range of functional groups in a simple step with tangible parameters and substrate adaptations. These rare 7-mrFPs are now accessible on a millimolar scale, and selected examples exhibit high antioxidant activity.
- Andreou, Dimitrios,Essien, Nsikak B.,Pubill-Ulldemolins, Cristina,Terzidis, Michael A.,Papadopoulos, Athanasios N.,Kostakis, George E.,Lykakis, Ioannis N.
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supporting information
p. 6685 - 6690
(2021/09/11)
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- Geometrically Selective Denitrative Trifluoromethylthiolation of β-Nitrostyrenes with AgSCF3for (E)-Vinyl Trifluoromethyl Thioethers
-
An efficient copper(II)-promoted denitrative trifluoromethylthiolation under mild reaction conditions has been developed for vinyl trifluoromethyl thioethers to construct Cvinyl-SCF3 bonds with stable AgSCF3 as a source of the trifluoromethylthio. This reaction system tolerates a broad range of functional groups to commendably achieve a high product yield and excellent stereoselectivity of E/Z.
- Fang, Ge,Hong, Jianquan,Huang, Shuai,Jiang, Chao,Liu, Yang,Zhang, Wei,Zheng, Changge
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supporting information
(2020/07/03)
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- NCC Pincer Ni (II) Complexes Catalyzed Hydrophosphination of Nitroalkenes with Diphenylphosphine
-
An efficient NCC pincer Ni (II)-catalyzed hydrophosphination of nitroalkenes with diphenylphosphine has been developed. Under the optimized conditions, both (hetero)aromatic and aliphatic nitroalkenes were well tolerated, irrespective of electronic effect, to provide the corresponding products in up to 99% yield.
- Yan, Jing,Wang, Yan-Bing,Hou, Senyao,Shi, Linlin,Zhu, Xinju,Hao, Xin-Qi,Song, Mao-Ping
-
-
- A Nickel-Bisdiamine Porous Organic Polymer as Heterogeneous Chiral Catalyst for Asymmetric Michael Addition to Aliphatic Nitroalkenes
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We report a polystyrene-incorporated chiral nickel(II)-bisdiamine complex, which is accessible on gram-scale. This metal complex functions as a heterogeneous catalyst for the enantioselective Michael addition between malonates and aliphatic nitroalkenes,
- Buendia, Mikkel B.,Kegn?s, S?ren,Kramer, S?ren
-
supporting information
p. 5506 - 5512
(2020/10/23)
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- Catalytic and Mechanistic Developments of the Nickel(II) Pincer Complex-Catalyzed Hydroarsination Reaction
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Synthetic challenges have significantly slowed the development of the catalytic asymmetric hydroarsination reaction despite it being a highly attractive C?As bond formation methodology. In addition, there is a poor understanding of the main reaction steps in such reactions which limit further development in the field. Herein, key intermediates of the hydroarsination reaction catalyzed by a PCP NiII-Cl pincer complex are presented upon investigating the reaction with DFT calculations, conductivity measurements, NMR spectroscopy, and catalytic screening. The novel Ni–Cl–As interaction proposed was then contrasted against known NiII-catalyzed hydrophosphination reactions to highlight dissimilarities between them even though P and As share a close group relationship. Lastly, the asymmetric hydroarsination of nitroolefins was further developed to furnish a library of chiral organoarsines in up to 99 % yield and 80 % ee under mild conditions (?20 °C to RT) between 5 to 210 mins.
- Tay, Wee Shan,Lu, Yunpeng,Yang, Xiang-Yuan,Li, Yongxin,Pullarkat, Sumod A.,Leung, Pak-Hing
-
supporting information
p. 11308 - 11317
(2019/08/07)
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- A Deprotonation Approach to the Unprecedented Amino-Trimethylenemethane Chemistry: Regio-, Diastereo-, and Enantioselective Synthesis of Complex Amino Cycles
-
The first realization of the amino-trimethylenemethane chemistry is reported using a deprotonation strategy to simplify the synthesis of the amino-trimethylenemethane donor in two steps from commercial and inexpensive materials. A broad scope of cycloaddition acceptors (seven different classes) participated in the chemistry, chemo-, regio-, diastereo-, and enantioselectively generating various types of highly valuable complex amino cycles. Multiple derivatization reactions that further elaborated the initial amino cycles were performed without isolation of the crude product. Ultimately, we applied the amino-trimethylenemethane chemistry to synthesize a potential pharmaceutical in 8 linear steps and 7.5 % overall yield, which previously was achieved in 18 linear steps and 0.6 % overall yield.
- Trost, Barry M.,Wang, Youliang
-
supporting information
p. 11025 - 11029
(2018/07/30)
-
- Enantioselective Conjugate Addition of 2-Acylimidazoles with Nitroalkenes Promoted by Chiral-at-Metal Rhodium(III) Complexes
-
An enantioselective conjugate addition of 2-acylimidazoles with nitroalkenes catalyzed by chiral-at-metal rhodium(III) complex under mild reaction conditions was developed, affording versatile γ-nitro ketone skeletons in good yields with excellent enantioselectivities (up to >99% ee). (Figure presented.).
- Thota, Ganesh Kumar,Sun, Gui-Jun,Deng, Tao,Li, Yi,Kang, Qiang
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supporting information
p. 1094 - 1098
(2018/01/22)
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- CuI-Catalysed Enantioselective Alkyl 1,4-Additions to (E)-Nitroalkenes and Cyclic Enones with Phosphino-Oxazoline Ligands
-
Catalytic enantioselective conjugate additions of simple alkyl groups to nitroalkenes or cyclic enones that result in the formation of tertiary C–C bonds are described. For these stereoselective addition reactions, new chiral phosphino-oxazoline ligands w
- Shin, Minkyeong,Gu, Minji,Lim, Sung Soo,Kim, Min-Jae,Lee, JuHyung,Jin, HyeongGyu,Jang, Yun Hee,Jung, Byunghyuck
-
supporting information
p. 3122 - 3130
(2018/07/06)
-
- Copper-Promoted Regioselective Synthesis of Polysubstituted Pyrroles from Aldehydes, Amines, and Nitroalkenes via 1,2-Phenyl/Alkyl Migration
-
The facile copper-catalyzed synthesis of polysubstituted pyrroles from aldehydes, amines, and β-nitroalkenes is reported. Remarkably, the use of α-methyl-substituted aldehydes provides efficient access to a series of tetra- and pentasubstituted pyrroles via an overwhelming 1,2-phenyl/alkyl migration. The present methodology is also accessible to non α-substituted aldehydes, yielding the corresponding trisubstituted pyrroles. On the contrary, the use of ketones, in place of aldehydes, does not promote the organic transformation, signifying the necessity of α-substituted aldehydes. The reaction proceeds under mild catalytic conditions with low catalyst loading (0.3-1 mol %), a broad scope, very good functional-group tolerance, and high yields and can be easily scaled up to more than 3 mmol of product, thus highlighting a useful synthetic application of the present catalytic protocol. Based on formal kinetic studies, a possible radical pathway is proposed that involves the formation of an allylic nitrogen radical intermediate, which in turn reacts with the nitroalkene to yield the desired pyrrole framework via a radical 1,2-phenyl or alkyl migration.
- Andreou, Dimitrios,Kallitsakis, Michael G.,Loukopoulos, Edward,Gabriel, Catherine,Kostakis, George E.,Lykakis, Ioannis N.
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p. 2104 - 2113
(2018/02/23)
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- Synthesis of Benzo[4,5]imidazo[2,1-b]thiazole by Copper(II)-Catalyzed Thioamination of Nitroalkene with 1H-Benzo[d]imidazole-2-thiol
-
A Copper(II)-catalyzed thioamination of β-nitroalkene with 1H-benzo[d]imidazole-2-thiol has been developed for the synthesis of benzo[4,5]imidazo[2,1-b]thiazole derivatives. A variety of N-fused benzoimidazothiazole derivatives are obtained in high yields through successive C?N and C?S bond formations. This protocol is also applicable to β-substituted β-nitroalkenes to afford 2,3-disubstituted benzoimidazothiazoles. (Figure presented.).
- Jana, Sourav,Chakraborty, Amrita,Shirinian, Valerii Z.,Hajra, Alakananda
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supporting information
p. 2402 - 2408
(2018/05/08)
-
- Continuous-flow synthesis using a column reactor packed with heterogeneous catalysts: A convenient production of nitroolefins by using amino-functionalized silicagel
-
A continuous-flow synthesis of β-nitroolefins by using heterogeneous base catalysts has been developed. Although the use of an excess amount of nitro-donor such as nitromethane is required in conventional methods, nearly equimolar amounts of nitro-donors and carbonyl compounds are sufficient for high-yielding production of nitroolefins. Catalysts for this flow protocol are inexpensive and abundant, and high durability and high productivity were also realized by using an appropriate second support.
- Ishitani, Haruro,Furiya, Yuichi,Kobayashi, Shū
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p. 6229 - 6232
(2017/09/30)
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- HETEROCYCLE AND CARBOCYCLE DERIVATIVES HAVING TRKA INHIBITORY ACTIVITY
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The present invention relates to a compound represented by Formula (I): wherein -L- is —C(═X)—, or the like, —Z— is —NR5—, or the like, —ZA— is —NR5A—, or the like, —W— is —C(R8R9)n-, —WA— is —C(R3R4)m-, B is substituted or unsubstituted aromatic carbocyclyl, or the like, Y is a bond, or the like, the ring C is a substituted or unsubstituted aromatic heterocycle, or the like, R2 is a hydrogen atom, or the like, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition comprising thereof.
- -
-
Paragraph 1327-1328
(2017/09/08)
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- K2S2O8-mediated nitration of alkenes with NaNO2 and 2,2,6,6-tetramethylpiperidine-1-oxyl: Stereoselective synthesis of (E)-nitroalkenes
-
A transition-metal-free nitration of alkenes with NaNO2 in the presence of K2S2O8 and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) is developed. The transformation exhibits a broad substrate scope and good functional group tolerance, thus providing a new and expedient protocol for stereoselective synthesis of (E)-nitroalkenes with moderate to good yields. Moreover, the nitration processes of (E)- and (Z)-stilbene are also studied: even though the proportion of substrates is different, the E/Z ratio of the products is basically the same. Based upon experimental observations, a possible reaction mechanism is proposed.
- Zhao, An,Jiang, Qing,Jia, Jing,Xu, Bin,Liu, Yufeng,Zhang, Mingzhong,Liu, Qiang,Luo, Weiping,Guo, Cancheng
-
supporting information
p. 80 - 84
(2015/12/23)
-
- Organocatalytic Enantioselective Transfer Hydrogenation of β-Amino Nitroolefins
-
The asymmetric organocatalytic transfer hydrogenation of β-acylamino and β-tert-butyloxycarbonylamino nitroolefins has been successfully realised in excellent enantioselectivities and yields (up to >99% ee, 97% yield) with a simple thiourea catalyst and a Hantzsch ester as hydrogen source, giving a direct access to enantiomerically pure β-amino nitroalkanes. (Figure presented.).
- Ferraro, Antonino,Bernardi, Luca,Fochi, Mariafrancesca
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p. 1561 - 1565
(2016/10/13)
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- Asymmetric Hydroazidation of Nitroalkenes Promoted by a Secondary Amine-Thiourea Catalyst
-
Chiral β-nitro azides are obtained by asymmetric addition of azides to nitroalkenes, with an enantioselectivity of up to 82% ee. The reaction, promoted by an easily accessible secondary amine-thiourea catalyst, is performed with azidotrimethylsilane in th
- Bellavista, Tiziana,Meninno, Sara,Lattanzi, Alessandra,Della Sala, Giorgio
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p. 3365 - 3373
(2015/11/03)
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- Clay-supported copper nitrate (claycop): A mild reagent for the selective nitration of aromatic olefins
-
A straightforward and highly selective method has been developed for the nitration of a wide variety of aromatic and aliphatic olefins by using a clay-supported copper nitrate (Claycop) and a catalytic amount of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl, an inexpensive and mild reagent system. High conversions and exclusive E-selectivity, together with the environmentally benign nature of the Claycop reagent, make this a green method and an attractive alternative to established methods. Georg Thieme Verlag Stuttgart. New York.
- Begari, Eeshwaraiah,Singh, Chandani,Nookaraju,Kumar, Pradeep
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p. 1997 - 2000
(2014/11/08)
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- 1,4-addition of TMSCCl3 to nitroalkenes: Efficient reaction conditions and mechanistic understanding
-
Improved synthetic conditions allow preparation of TMSCCl3 in good yield (70 %) and excellent purity. Compounds of the type NBu4X [X=Ph3SiF2 (TBAT), F (tetrabutylammonium fluoride, TBAF), OAc, Cl and Br] act as catalytic promoters for 1,4-additions to a range of cyclic and acyclic nitroalkenes, in THF at 0-25 °C, typically in moderate to excellent yields (37-95 %). TBAT is the most effective promoter and bromide the least effective. Multinuclear NMR studies (1H, 19F, 13C and 29Si) under anaerobic conditions indicate that addition of TMSCCl3 to TBAT (both 0.13 M) at -20 °C, in the absence of nitroalkene, leads immediately to mixtures of Me3SiF, Ph3SiF and NBu4CCl3. The latter is stable to at least 0 °C and does not add nitroalkene from -20 to 0 °C, even after extended periods. Nitroalkene, in the presence of TMSCCl3 (both 0.13 M at -20 °C), when treated with TBAT, leads to immediate formation of the 1,4-addition product, suggesting the reaction proceeds via a transient [Me 3Si(alkene)CCl3] species, in which (alkene) indicates an Si O coordinated nitroalkene. The anaerobic catalytic chain is propagated through the kinetic nitronate anion resulting from 1,4 CCl3 - addition to the nitroalkene. This is demonstrated by the fact that isolated NBu4[CH2=NO2] is an efficient promoter. Use of H2C=CH(CH2)2CH=CHNO 2 in air affords radical-derived bicyclic products arising from aerobic oxidation. Understanding TMSCCl3: The synthesis and reactivity of TMSCCl3 has been investigated. The mechanism of 1,4-CCl3 addition to nitroalkenes begins with nitroalkene coordination, followed by the attack of an external fluoride ion, and does not involve the formation of NBu4[Me3SiFCCl3] (see figure).
- Wu, Na,Wahl, Benoit,Woodward, Simon,Lewis, William
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p. 7718 - 7724
(2014/07/07)
-
- Useful extensions of the henry reaction: Expeditious routes to nitroalkanes and nitroalkenes in aqueous media
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The products of the Henry nitroaldol reaction from nitromethane and several aldehydes were reduced to the corresponding nitroalkanes with (n-Bu) 3SnH in water under microwave irradiation (80 °C/10 min), or dehydrated to the corresponding nitroalkenes with K2CO3 in water (generally 0-5 °C/20 min). Both "one-pot" reactions occur in excellent yields across a range of aliphatic and aromatic (including heteroaromatic) substrates. It seems likely that the deoxygenation of the nitroaldols occurs via coordination of an oxygen atom of the nitro group with a tin atom, which facilitates hydride delivery in the transition state. The elimination of water from the nitroaldols in mild base is likely driven by the stability of the conjugated nitroalkene products. The elimination required workup with 2 N HCl, which likely displaces a nitroalkane-nitroalkene equilibrium towards the latter. These extensions of the Henry reaction lead to products not easily obtained otherwise.
- Chandrasekhar, Sosale,Shrinidhi, Annadka
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p. 3008 - 3018
(2014/10/16)
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- Highly efficient iridium-catalyzed asymmetric hydrogenation of β-acylamino nitroolefins
-
The first highly efficient Ir-catalyzed enantioselective hydrogenation of β-acylamino nitroolefins is reported. This reaction provides straightforward access to chiral β-amino nitroalkanes in high yields and excellent enantioselectivities (up to >99.9% ee) catalyzed by an Ir-(R,R)-f-spiroPhos complex. This journal is
- Yan, Qiaozhi,Liu, Man,Kong, Duanyang,Zi, Guofu,Hou, Guohua
-
supporting information
p. 12870 - 12872
(2014/12/11)
-
- Efficient and stereoselective nitration of mono- and disubstituted olefins with AgNO2 and TEMPO
-
Nitroolefin is a common and versatile reagent. Its synthesis from olefin is generally limited by the formation of mixture of cis and trans compounds. Here we report that silver nitrite (AgNO2) along with TEMPO can promote the regio- and stereoselective nitration of a broad range of olefins. This work discloses a new and efficient approach wherein starting from olefin, nitroalkane radical formation and subsequent transformations lead to the desired nitroolefin in a stereoselective manner.
- Maity, Soham,Manna, Srimanta,Rana, Sujoy,Naveen, Togati,Mallick, Arijit,Maiti, Debabrata
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supporting information
p. 3355 - 3358
(2013/04/10)
-
- Stereoselective nitration of olefins with tBuONO and TEMPO: Direct access to nitroolefins under metal-free conditions
-
Nitroolefins are essential elements for both synthetic chemistry and medicinal research. Despite significant improvements in nitration of olefin an efficient metal-free synthesis remains elusive so far. Herein, we disclose a new set of reagents to access nitroolefins in a single step under metal-free conditions. A wide range of olefins with diverse functionalities has been nitrated in synthetically useful yields. This transformation is operationally simple and exhibits excellent E-selectivity. Furthermore, site selective nitration in a complex setup makes this method advantageous.
- Maity, Soham,Naveen, Togati,Sharma, Upendra,Maiti, Debabrata
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supporting information
p. 3384 - 3387
(2013/07/26)
-
- A predictably selective nitration of olefin with Fe(NO3) 3 and TEMPO
-
Ferric nitrate with catalytic TEMPO has been identified as a useful reagent for regio- and stereoselective nitration of a wide variety of aromatic, aliphatic, and heteroaromatic olefins. This reaction provided nitroolefins in preparatively useful yields with excellent E-selectivity. Due to its mild nature and operational simplicity, the present protocol is expected to find application in synthetic setup.
- Naveen, Togati,Maity, Soham,Sharma, Upendra,Maiti, Debabrata
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p. 5949 - 5954
(2013/07/26)
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- Synthesis of nitroalkenes involving a cooperative catalytic action of iron(III) and piperidine: A one-pot synthetic strategy to 3-alkylindoles, 2H-chromenes and N-arylpyrrole
-
An efficient and simple strategy has been developed to synthesize various substituted nitroalkenes involving a cooperative catalytic system of FeCl 3 and piperidine. This dual catalytic protocol simultaneously activates both electrophile and nucleophile and works under mild reaction conditions so that many sensitive functional groups were tolerated. Moreover, this cooperative catalytic reaction is also suitable for various one-pot reactions involving nitroalkenes such as, 2H-chromenes, N-arylpyrrole and Michael reaction with indole. Notably, this method is low-cost, efficient and environmentally friendly. Copyright
- Jalal, Swapnadeep,Sarkar, Soumen,Bera, Krishnendu,Maiti, Sukhendu,Jana, Umasish
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supporting information
p. 4823 - 4828
(2013/08/23)
-
- Asymmetric palladium(II)-catalyzed cascade reaction giving quaternary amino succinimides by 1,4-addition and a nef-type reaction
-
Simple starting materials, high-value products: A dinuclear ferrocene-based PdII complex transforms mixtures of racemic N-benzoyl α-amino acids, nitroolefins, acetic anhydride, and manganese acetate into biologically interesting quaternary amin
- Weber, Manuel,Frey, Wolfgang,Peters, Rene
-
supporting information
p. 13223 - 13227
(2014/01/06)
-
- Enantioselective nickel-catalyzed michael additions of 2-acetylazaarenes to nitroalkenes
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2-Acetylazaarenes undergo catalytic enantioselective Michael additions to nitroalkenes in the presence of a chiral Ni(II)-bis(oxazoline) complex. The process is tolerant of a range of azines or azoles in the pronucleophilic component, resulting in Michael products in moderate to high enantioselectivities.
- Simpson, Alain J.,Lam, Hon Wai
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p. 2586 - 2589
(2013/07/26)
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- Asymmetric N-heterocyclic carbene catalyzed addition of enals to nitroalkenes: Controlling stereochemistry via the homoenolate reactivity pathway to access δ-lactams
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An asymmetric intermolecular reaction between enals and nitroalkenes to yield δ-nitroesters has been developed, catalyzed by a novel chiral N-heterocyclic carbene. Key to this work was the development of a catalyst that favors the δ-nitroester pathway over the established Stetter pathway. The reaction proceeds in high stereoselectivity and affords the previously unreported syn diastereomer. We also report an operationally facile two-step, one-pot procedure for the synthesis of δ-lactams.
- White, Nicholas A.,Dirocco, Daniel A.,Rovis, Tomislav
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p. 8504 - 8507
(2013/07/19)
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- Asymmetric addition of cyanide to β-nitroalkenes catalysed by chiral salen complexes of Titanium(IV) and Vanadium(V)
-
Structurally well-defined bimetallic titanium(IV) (salen) and monometallic vanadium(V) (salen) complexes have been used as catalysts for the asymmetric addition of trimethylsilyl cyanide to β-nitroalkenes to produce chiral nitronitriles with ee values in the range of 79-89% and conversions up to 100% at 0°C. The reaction conditions (solvent, temperature, time and vanadium complex counter-ion) were optimised, and it was shown that the catalyst loading could be significantly reduced (20 to 2mol%) and the reaction temperature increased (-40 to 0°C) compared to previous studies that used an insitu prepared catalyst. The results are compared and contrasted with previous results obtained by using the same catalysts for the asymmetric addition of trimethylsilyl cyanide to aldehydes, and a transition-state structure for the asymmetric addition of trimethylsilyl cyanide to nitroalkenes is proposed to account for the observed stereochemistry.
- North, Michael,Watson, James M.
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p. 2405 - 2409
(2013/08/23)
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- TRIAZOLIUM CARBENE CATALYSTS AND PROCESSES FOR ASYMMETRIC CARBON-CARBON BOND FORMATION
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Provided herein are chiral triazolium catalysts useful for asymmetric C-C bond formation and processes for their preparation. Also provided are synthetic reactions in which these catalysts are used, in particular, in asymmetric C-C bond formation.
- -
-
Page/Page column 27-28
(2012/02/02)
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- Rh(I)-catalyzed enantioselective hydrogenation of α-substituted ethenylphosphonic acids
-
A class of chiral Rh(I) catalysts containing monodentate phosphorous acid diesters tautomerized from the corresponding secondary phosphine oxides was discovered by serendipitous hydrolysis of phosphoramidite ligands. The evolved catalysts demonstrated unprecedented enantioselectivities (98-99% ee) and high catalytic activities (as low as 0.01 mol% catalyst loading) in asymmetric hydrogenations of a wide variety of α-aryl-/alkyl-substituted ethenylphosphonic acids, providing a facile approach to the corresponding enantiopure phosphonic acids with significant biological importance.
- Dong, Kaiwu,Wang, Zheng,Ding, Kuiling
-
supporting information; experimental part
p. 12474 - 12477
(2012/09/05)
-
- One-pot asymmetric synthesis of γ-nitroaldehydes from aldehydes and nitroalkanes through a catalytic tandem reaction using an amino acid lithium salt
-
One-pot asymmetric synthesis of γ-nitroaldehydes from aldehydes and nitroalkanes was achieved by a catalytic tandem reaction using a primary amino acid lithium salt, O-tert-butyldiphenylsilyl l-tyrosine lithium salt, as a catalyst. Various aryl, alkenyl, and alkyl aldehydes were converted into γ-nitroaldehydes via in situ generation of nitroalkenes.
- Yoshida, Masanori,Kitamikado, Naoki,Ikehara, Hiroto,Hara, Shoji
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experimental part
p. 2305 - 2309
(2011/06/11)
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- Dual hydrogen-bond/enamine catalysis enables a direct enantioselective three-component domino reaction
-
It takes two to tango: A dual catalyst system, composed of a highly enantioselective enamine catalyst and a multiple-hydrogen-bond catalyst, enabled the chemoselective union of two aldehydes and a nitromethane unit with near-perfect enantioselectivities, excellent diastereoselectivities, and high yields under neutral conditions (see scheme). Copyright
- Rahaman, Hasibur,Madarasz, Udam,Papai, Imre,Pihko, Petri M.
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supporting information; experimental part
p. 6123 - 6127
(2011/08/05)
-
- Cascade formation of isoxazoles: Facile base-mediated rearrangement of substituted oxetanes
-
Give me five! Nitro compounds and oxetan-3-one react through an intriguing cascade sequence to give isoxazole-4-carbaldehydes using inexpensive reagents in a one-pot procedure (see scheme; Ms=methanesulfonyl). A variety of 3-substituted isoxazole-4-carbaldehydes were obtained in high overall yields.
- Burkhard, Johannes A.,Tchitchanov, Boris H.,Carreira, Erick M.
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p. 5379 - 5382
(2011/07/08)
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- Catalytic asymmetric intermolecular stetter reaction of enals with nitroalkenes: Enhancement of catalytic efficiency through bifunctional additives
-
An asymmetric intermolecular Stetter reaction of enals with nitroalkenes catalyzed by chiral N-heterocyclic carbenes has been developed. The reaction rate and efficiency are profoundly impacted by the presence of catechol. The reaction proceeds with high selectivities and affords good yields of the Stetter product. Internal redox products were not observed despite of the protic conditions. The impact of catechol has been found to be general, facilitating far lower catalyst loadings than were previously achievable.
- Dirocco, Daniel A.,Rovis, Tomislav
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p. 10402 - 10405
(2011/08/22)
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- Versatile synthesis of α-substituted taurines from nitroolefins
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A series of 1-substituted and 1,1-disubstituted taurines were synthesized from nitroolefins via the Michael addition with sodium ethylxanthate, oxidation with performic acid, and reduction with hydrogen in the presence of palladium on carbon powder. The current route is a versatile and salt-free method for synthesis of both aliphatic and aromatic 1-substituted and 1,1-disubstituted taurines. Springer-Verlag 2010.
- Xu, Chuanxiang,Xu, Jiaxi
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experimental part
p. 195 - 203
(2012/04/10)
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- Platinum-catalyzed michael addition and cyclization of tertiary amines with nitroolefins by dehydrogenation of α,β-sp3 C-H bonds
-
A mild platinum-catalyzed oxidative dehydrogenation of α,β- C(sp3)-H bonds of tertiary amines in the presence of ambient oxygen is revealed, and the in situ formed enamines subsequently reacting with various nitroolefins resulted in the development of two one-pot synthetic protocols involving Michael addition-elimination and Michael addition-cyclization. By using different functionalized nitroolefins compatible with the current oxidative conditions, two types of structurally divergent products, trisubstituted enamines and chromano[2,3-b]piperidines, could be expediently accessed, respectively.
- Xia, Xiao-Feng,Shu, Xing-Zhong,Ji, Ke-Gong,Yang, Yan-Fang,Shaukat, Ali,Liu, Xue-Yuan,Liang, Yong-Min
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supporting information; experimental part
p. 2893 - 2902
(2010/07/09)
-
- Optimization of privileged structures for selective and potent melanocortin subtype-4 receptor ligands
-
Design, syntheses and structure-activity relationships of N-acetylated piperazine privileged structures containing MC4R agonist compounds were described. The most potent derivatives were low nM MC4R selective full agonists. Several compounds from the series had modest pharmacokinetic properties.
- Hong, Qingmei,Bakshi, Raman K.,Dellureficio, James,He, Shuwen,Ye, Zhixiong,Dobbelaar, Peter H.,Sebhat, Iyassu K.,Guo, Liangqin,Liu, Jian,Jian, Tianying,Tang, Rui,Kalyani, Rubana N.,MacNeil, Tanya,Vongs, Aurawan,Rosenblum, Charles I.,Weinberg, David H.,Peng, Qingping,Tamvakopoulos, Constantin,Miller, Randy R.,Stearns, Ralph A.,Cashen, Doreen,Martin, Willian J.,Chen, Airu S.,Metzger, Joseph M.,Chen, Howard Y.,Strack, Allison M.,Fong, Tung M.,MacLntyre, Euan,Van Der Ploeg, Lex H.T.,Wyvratt, Matthew J.,Nargund, Ravi P.
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scheme or table
p. 4483 - 4486
(2010/10/02)
-
- Catalytic asymmetric intermolecular stetter reaction of heterocyclic aldehydes with nitroalkenes: Backbone fluorination improves selectivity
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(Chemical Equation Presented) The catalytic asymmetric intermolecular Stetter reaction of heterocyclic aldehydes and nitroalkenes has been developed. We have identified a strong stereoelectronic effect on catalyst structure when a fluorine substituent is
- DiRocco, Daniel A.,Oberg, Kevin M.,Dalton, Derek M.,Rovis, Tomislav
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supporting information; experimental part
p. 10872 - 10874
(2009/12/03)
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- Asymmetric Friedel-Crafts alkylation of pyrroles with nitroalkenes using a dinuclear zinc catalyst
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The catalytic enantioselective and atom economic Friedel-Crafts alkylation of pyrroles with nitroalkenes under mild reaction conditions using a dinuclear zinc catalyst is reported. The versatility of the reaction is demonstrated by the conversion of a number of differentially substituted nitroalkenes with differentially substituted pyrroles. Tandem addition reactions to form 2,5-disubstituted pyrroles are also demsonstrated. All pyrrole alkylations have been carried out without using N-protecting groups, which also enhances the efficiency by which substituted pyrroles may be synthesized. The reactions result in good yields and excellent enantioselectivities. Copyright
- Trost, Barry M.,Mueller, Christoph
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p. 2438 - 2439
(2008/09/19)
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- A general one-step synthesis of β-nitronitriles
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(Chemical Equation Presented) The unusual β-nitronitrile functionality was prepared by a simple one-step Kydrocyanation of nitroalkenes. These compounds were shown to be precursors to monoprotected 1,3-diamines and 1,3-amino alcohols through the in situ f
- Anderson, James C.,Blake, Alexander J.,Mills, Matthew,Ratcliffe, Paul D.
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supporting information; experimental part
p. 4141 - 4143
(2009/05/27)
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- Acid-base bifunctional catalysis of silica-alumina-supported organic amines for carbon-carbon bond-forming reactions
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Acid-base bifunctional heterogeneous catalysts were prepared by the reaction of an acidic silica-alumina (SA) surface with silane-coupling reagents possessing amino functional groups. The obtained SA-supported amines (SA-NR 2) were characterized by solid-state 13C and 29Si NMR spectroscopy, FT-IR spectroscopy, and elemental analysis. The solid-state NMR spectra revealed that the amines were immobilized by acid-base interactions at the SA surface. The interactions between the surface acidic sites and the immobilized basic amines were weaker than the interactions between the SA and free amines. The catalytic performances of the SA-NR 2 catalysts for various carbon-carbon bond-forming reactions, such as cyano-ethoxycarbonylation, the Michael reaction, and the nitro-aldol reaction, were investigated and compared with those of homogeneous and other heterogeneous catalysts. The SA-NR2 catalysts showed much higher catalytic activities for the carbon-carbon bond-forming reactions than heterogeneous amine catalysts using other supports, such as SiO2 and Al 2O3. On the other hand, homogeneous amines hardly promoted these reactions under similar reaction conditions, and the catalytic behavior of SA-NR2 was also different from that of MgO, which was employed as a typical heterogeneous base. An acid-base dual-activation mechanism for the carbon-carbon bond-forming reactions is proposed.
- Motokura, Ken,Tomita, Mitsuru,Tada, Mizuki,Iwasawa, Yasuhiro
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experimental part
p. 4017 - 4027
(2009/05/07)
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- A convenient samarium-promoted synthesis of aliphatic (E)-nitroalkenes under mild conditions
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(Chemical Equation Presented) A samarium-promoted synthesis of (E)-nitroalkenes from 1-bromo-1-nitroalkan-2-ols in high yields and with total selectivity is reported. This reaction together with the easy and efficient preparation of the 1-bromo-1-nitroalk
- Concellon, Jose M.,Bernad, Pablo L.,Rodriguez-Solla, Humberto,Concellon, Carmen
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p. 5421 - 5423
(2008/02/08)
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- Application of the chiral bis(phosphine) monoxide ligand to catalytic enantioselective addition of dialkylzinc reagents to β-nitroalkenes
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(Chemical Equation Presented) Me-DuPHOS monoxide is shown to be a very effective ligand in the enantioselective copper-catalyzed addition of dialkylzinc reagents to β-nitroalkenes providing access to chiral nitroalkanes. The major advantages of this process are high yields, broad and complementary substrate scope, and high enantioselectivities. The effect of achiral dummy ligands as an additive has also been documented.
- Cote, Alexandre,Lindsay, Vincent N. G.,Charette, Andre B.
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- One-pot multi-substrate enantioselective conjugate addition of diethylzinc to nitroalkenes
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A multi-substrate approach is used in the copper-phosphoramidite catalyzed enantioselective conjugate addition of diethylzinc to nitroalkenes, using up to nine different nitroalkenes in a one pot procedure. The 18 products (9 times 2 enantiomers of nine d
- Duursma, Ate,Minnaard, Adriaan J,Feringa, Ben L
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p. 5773 - 5778
(2007/10/03)
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- Enantioselective synthesis of α-amino acids and monosubstituted 1,2- diamines by conjugate addition of 4-phenyl-2-oxazolidinone to nitroalkenes
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The addition of the potassium salt of (R)- or (S)-4-phenyl-2- oxazolidinone to monosubstituted nitroalkenes proceeded with very good diastereoselectivity. Several of the addition products were converted into α-amino acids and monosubstituted 1,2-diamines of high enantiomeric purity.
- Lucet, Denis,Sabelle, Stephane,Kostelitz, Olivier,Le Gall, Thierry,Mioskowski, Charles
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p. 2583 - 2591
(2007/10/03)
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- A General Method for the Preparation of 2,2-Disubstituted 1-Nitroalkenes
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A general and expeditious route for the preparation of functionalized 2,2-disubstituted 1-nitroalkenes has been developed.Conjugate 1,4-addition of complex zinc cuprates (RCu(CN)ZnI) to easily obtained (E)-1-nitroalkenes, followed by trapping with phenylselenenyl bromide and subsequent oxidative elimination, afforded the corresponding 2,2-disubstituted 1-nitroalkenes in good yields. 2-Alkyl-2-aryl- and 2,2-dialkyl nitroalkenes 4b-g were prepared in 76-88percent yield and obtained as E/Z isomeric mixtures, slightly favoring the Z isomer (ca. 1.0:1.5, E/Z).
- Denmark, Scott E.,Marcin, Lawrence R.
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p. 3850 - 3856
(2007/10/02)
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- Highly stereoselective preparation of nitro olefins and nitro dienes by the addition-elimination of copper-zinc organometallics to β-alkylthio and β-phenylsulfonyl nitro olefins
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The addition-elimination of copper-zinc organometallics RCu(CN)ZnX to (E)-1-nitro-2-phenylsulfonyl ethylene 2a gave highly functionalized pure (E) nitro olefins and stereoselectively (1E, 3E) and (1E, 3Z)-1-nitrodienes in excellent yields. β-Alkylthio nit
- Retherford,Knochel
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p. 441 - 444
(2007/10/02)
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