- Chiral enantiopure organosilane precursors for the synthesis of periodic mesoporous organosilicas
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The manuscript describes synthesis of new chiral organosilica networks starting from modified readily available enantiopure substances such as sugars and amino acids. We report on the successful preparation of robust all-chiral organosilicas by polymerization of the homochiral monomers. When the homochiral organosilane monomers were polymerized in mixtures of polar organic solvents and water in the presence of hydrochloric acid or tetrabutylammonium fluoride as catalysts, mainly spherical microparticles were obtained due to emulsification of the hydrophobic monomers in these mixtures. Polycondensation of the chiral organosilanes in the presence of Pluronic P123 as a template produced ordered mesoporous networks. The new all-chiral materials were characterized by SEM, STEM, BET, SAXS, IR, NMR and TGA.
- Cohen, Orit,Abu-Reziq, Raed,Gelman, Dmitri
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- Selective hydrogenation of primary amides and cyclic di-peptides under Ru-catalysis
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A ruthenium(II)-catalyzed selective hydrogenation of challenging primary amides and cyclic di-peptides to their corresponding primary alcohols and amino alcohols, respectively, is reported. The hydrogenation reaction operates under mild and eco-benign conditions and can be scaled-up.
- Subaramanian, Murugan,Sivakumar, Ganesan,Babu, Jessin K.,Balaraman, Ekambaram
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supporting information
p. 12411 - 12414
(2020/10/30)
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- Enantiodivergent Synthesis of (+)- and (?)-Pyrrolidine 197B: Synthesis of trans-2,5-Disubstituted Pyrrolidines by Intramolecular Hydroamination
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A highly efficient, diastereoselective, iron(III)-catalyzed intramolecular hydroamination/cyclization reaction involving α-substituted amino alkenes is described. Thus, enantiopure trans-2,5-disubstituted pyrrolidines and trans-5-substituted proline derivatives were synthesized by means of a combination of enantiopure starting materials, easily available from l-α-amino acids, with sustainable metal catalysts such as iron(III) salts. The scope of this methodology is highlighted in an enantiodivergent approach to the synthesis of both (+)- and (?)-pyrrolidine 197B alkaloids from l-glutamic acid. In addition, a computational study was carried out to gain insight into the complete diastereoselectivity of the transformation.
- Pérez, Sixto J.,Purino, Martín A.,Cruz, Daniel A.,López-Soria, Juan M.,Carballo, Rubén M.,Ramírez, Miguel A.,Fernández, Israel,Martín, Víctor S.,Padrón, Juan I.
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supporting information
p. 15529 - 15535
(2016/10/13)
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- Metal-free one-pot synthesis of 2-substituted and 2,3-disubstituted morpholines from aziridines
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The metal-free synthesis of 2-substituted and 2,3-disubstituted morpholines through a one-pot strategy is described. A simple and inexpensive ammonium persulfate salt enables the reaction of aziridines with halogenated alcohols to proceed via an SN2-type ring opening followed by cyclization of the resulting haloalkoxy amine.
- Sun, Hongnan,Huang, Binbin,Lin, Run,Yang, Chao,Xia, Wujiong
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supporting information
p. 524 - 529
(2015/06/08)
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- Modular, One-Pot, Sequential Aziridine Ring Opening-SNAr Strategy to 7-, 10-, and 11-Membered Benzo-Fused Sultams
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The generation of common and stereochemically rich medium-sized benzo-fused sultams via complementary pairing of heretofore-unknown (o-fluoroaryl)sulfonyl aziridine building blocks with an array of amino alcohols/amines in a modular one-pot, sequential protocol using an aziridine ring opening and intramolecular nucleophilic aromatic substitution is reported. The strategy employs a variety of amino alcohols/amines and proceeds with 6 + 4/6 + 5 and 6 + 1 cycloetherification pathways in a highly chemo- and regioselective fashion to obtain skeletally and structurally diverse, polycyclic, 10- to 11- and 7-membered benzo-fused sultams for broad-scale screening.
- Loh, Joanna K.,Asad, Naeem,Samarakoon, Thiwanka B.,Hanson, Paul R.
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p. 9926 - 9941
(2015/11/03)
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- Readily available ferrocenyl-phosphinite ligands for Ru(II)-catalyzed enantioselective transfer hydrogenation of ketones and fabrication of hybrid heterojunctions
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A variety of phosphinite based on ferrocenyl moiety possessing central chirality have been screened as ligands for ruthenium(II)-catalyzed transfer hydrogenation of acetophenone derivatives using iso-PrOH as the hydrogen source to afford the corresponding product, (R) or (S)-1-phenylethanol derivatives with high conversions and good enantioselectivities. These complexes were also employed in the asymmetric reduction of different prochiral ketones (up to 85% ee). A comparison of the catalytic properties of amino alcohols and other analogs based on ferrocenyl backbone is also discussed briefly. The structures of these ligands and their corresponding complexes have been elucidated by a combination of multinuclear NMR spectroscopy, IR spectroscopy and elemental analysis. Furthermore, organic-inorganic hybrid heterojunctions were also fabricated by forming thin films of ruthenium(II) complexes on n-Si and evaporation of Au as front contact. Current-voltage (I-V) characteristics of the structures showed excellent rectification properties. Electrical parameters including ideality factor, barrier height and series resistance were determined using I-V and capacitance-voltage (C-V) data. Finally, photoelectrical properties of the structures were examined by means of a solar simulator with AM1.5 global filter.
- Ak, Bünyamin,Aydemir, Murat,Ocak, Yusuf Selim,Durap, Feyyaz,Kayan, Cezmi,Baysal, Akin,Temel, Hamdi
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p. 244 - 253
(2013/12/04)
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- Enantio- and diastereoselective palladium catalysed arylative and vinylative allene carbocyclisation cascades
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The enantioselective synthesis of heavily decorated spirolactams has been accomplished via an arylative or vinylative allene carbocyclisation cascade. Mediated by silver phosphate, a range of allene-linked pro-nucleophiles and aryl or vinyl iodides were reacted in the presence of catalytic Pd(OAc)2 and chiral bis(oxazoline) ligands to afford the spirolactam products in good yields and high enantio- and diastereoselectivities. The Royal Society of Chemistry 2013.
- Li, Meiling,Hawkins, Alison,Barber, David M.,Bultinck, Patrick,Herrebout, Wouter,Dixon, Darren J.
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supporting information
p. 5265 - 5267
(2013/06/27)
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- Tetrahydroquinoline-derived macrocyclic toolbox: The discovery of antiangiogenesis agents in zebrafish assay
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A novel approach to incorporate the macrocyclic rings onto the privileged substructure, i.e., tetrahydroquinoline scaffold, is developed. The presence of an amino acid-derived moiety in the macrocyclic skeleton provides an opportunity to modulate the nature of the chiral side chain. Further, evaluation in a zebrafish screen identified three active small molecules (2.5b, 3.2d, and 4.2) as antiangiogenesis agents at 2.5 μM.
- Reddy Guduru, Shiva Krishna,Chamakuri, Srinivas,Chandrasekar, Gayathri,Kitambi, Satish Srinivas,Arya, Prabhat
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supporting information
p. 666 - 670
(2013/07/26)
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- Screening of C2-symmetric chiral phosphinites as ligands for ruthenium(II)-catalyzed asymmetric transfer hydrogenation of prochiral aromatic ketones
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Metal-catalyzed transfer hydrogenation processes provide a widely-used alternative to direct hydrogenation processes of ketones. As part of an ongoing program, we report enantioselective C2-symmetric bis(phosphinite)- ruthenium(II) catalytic systems for the transfer hydrogenation of prochiral aromatic ketones. The new catalytic systems can readily be formed under in situ conditions from C2-symmetric chiral bis(phosphinite) ligands and [Ru(η6-p-cymene)(μ-Cl)Cl]2 in transfer hydrogenation reaction media. These chiral ruthenium catalytic systems serve as catalyst precursors for the asymmetric transfer hydrogenation of acetophenone derivatives in iso-PrOH and giving the corresponding optical active secondary alcohols up to 94% ee.
- Elma, Duygu,Durap, Feyyaz,Aydemir, Murat,Baysal, Akin,Meric, Nermin,Ak, Bünyamin,Turgut, Ylmaz,Gümgüm, Bahattin
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- Tunable ferrocenyl-phosphinite ligands for the ruthenium(II)-catalyzed asymmetric transfer hydrogenation of ketones
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We report here new examples of enantiomerically pure monodendate phosphinite ligands containing both a ferrocene moiety and NH bridging moiety adjacent to the stereocenter, as well as their ruthenium(II) dichloro complexes. The phosphinites based on ferrocenyl moiety possessing stereogenic center have been screened as ligands for ruthenium(II)-catalyzed transfer hydrogenation of aromatic ketones to give corresponding secondary alcohols using iso-PrOH as the hydrogen source in the presence of NaOH. Up to 99% conversion with 97% ee was obtained in the transfer hydrogenation of acetophenone derivatives. Furthermore, the catalytic properties of these catalysts based on ferrocenyl-phosphinite backbone are also discussed briefly. The structures of these ligand and their corresponding complexes have been elucidated by a combination of multinuclear NMR spectroscopy, IR spectroscopy and elemental analysis.
- I?ik, U?ur,Aydemir, Murat,Meri?, Nermin,Durap, Feyyaz,Kayan, Cezmi,Temel, Hamdi,Baysal, Akin
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p. 225 - 233
(2013/10/08)
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- Green asymmetric synthesis: β-amino alcohol-catalyzed direct asymmetric aldol reactions in aqueous micelles
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The ability of chiral β-amino alcohols to catalyze the direct asymmetric aldol reaction was evaluated for the first time in aqueous micellar media. A family of cheap and easily accessible β-amino alcohols, obtained in one step from naturally occurring amino acids, was shown to successfully catalyze the asymmetric aldol reaction between a series of ketones and aromatic aldehydes. These aldol reactions furnished the corresponding β-hydroxy ketones with up to 93% isolated yield and 89% ee. (S)-2-phenylglycinol and Triton X-100 proved to be the best organocatalyst and surfactant, respectively. Copyright
- Pinaka, Afroditi,Vougioukalakis, Georgios C.,Dimotikali, Dimitra,Yannakopoulou, Elina,Chankvetadze, Bezhan,Papadopoulos, Kyriakos
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p. 119 - 125
(2013/08/24)
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- A convenient one-step synthesis of stable β-amino alcohol N-boranes from α-amino acids
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Novel, non-cyclic -amino alcohol N-boranes are isolated from the sodium borohydride-sulfuric acid assisted direct reduction of a series of -amino acids. The reduction takes place in one step under mild conditions and affords the products in good yields. Georg Thieme Verlag Stuttgart · New York.
- Pinaka, Afroditi,Vougioukalakis, Georgios C.,Dimotikali, Dimitra,Psyharis, Vassilis,Papadopoulos, Kyriakos
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experimental part
p. 1057 - 1062
(2012/05/21)
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- Synthesis of novel N-protected β3-amino nitriles: study of their hydrolysis involving a nitrilase-catalyzed step
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Several commercially available nitrilases were investigated with regard to their potential to hydrolyze N-protected β3-amino nitriles into their corresponding N-protected β3-amino acids. The biotransformations were obtained in different proportions depending on the nitrilase involved. The best hydrolysis results were achieved for the N-Cbz-β3-amino nitrile from l-alanine using the NIT-107, in a phosphate buffer at 0.05 M. However, no biotransformation into the corresponding acids was observed for the N-sulfonylamide β3-amino nitriles. Two simple and efficient procedures to prepare the β3-amino nitriles from their analogous α-amino acids are described. Thirty four new substances were synthesized and characterized over the course of this work.
- Veitia, Maite Sylla-Iyarreta,Brun, Pierre Louis,Jorda, Pierre,Falguieres, Annie,Ferroud, Clotilde
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scheme or table
p. 2077 - 2089
(2010/03/04)
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- Asymmetric epoxidation of styrenes catalyzed by molybdenum complexes with amino alcohol ligands
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Two common amino alcohols, prolinol and isolucinol, and their derivatives have been screened to coordinate with MoO2(acac)2 to form in situ catalysts for asymmetric epoxidation of styrenes with the highest enantioselectivity of 84% for 4-fluoro-styrene under the optimized reaction conditions.
- Wang, Yi,Wu, Zhiqing,Li, Zhengkai,Zhou, Xiang-Ge
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body text
p. 2509 - 2511
(2009/09/05)
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- Syntheis of new chiral 5,6,7,8-tetrahydrotetrazolo[1,5-a]pyrazines from α-amino acid derivatives following "click" chemistry
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An efficient and practical synthesis of new chiral fused tetrazoles have been synthesized following [3+2] cycloaddition reaction starting from α-amino acid derivatives.
- Mohapatra, Debendra K.,Maity, Pradip K.,Ghorpade, Ravindra V.,Gurjar, Mukund K.
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body text
p. 865 - 872
(2010/09/16)
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- REVERSIBLE ROOM-TEMPERATURE IONIC LIQUIDS
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One aspect of the present invention relates to salts that are room-temperature ionic liquids (RTILs), methods of making them, and methods of using them in connection with temporary or permanent gas sequestration. Another aspect of the present invention relates to a class of solvents which can be transformed into RTILs by exposure to a gas, and methods of using them in connection with temporary or permanent gas sequestration.
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Page/Page column 6; 94; 96-98; Sheet 15/20
(2008/12/07)
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- Synthesis of chiral polydentate ligands and the use of their titanium complexes as pre-catalysts for the asymmetric trimethylsilylcyanation of benzaldehyde
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A number of polydentate ligands based on enantiomerically pure binaphthol have been synthesized. The ligand complexes with titanium isopropoxide were used as catalysts for the asymmetric addition of trimethylsilyl cyanide to benzaldehyde. A fragment with axial chirality is responsible for the configuration of O-trimethylsilyl cyanohydrin product. In the case of the optimum ligand based on (R)-binaphthol and (S)-leucinol, an enantiomeric excess of 86% and quantitative yield were achieved in 4 h.
- Belokon,Chusov,Skrupskaya,Bor'Kin,Yashkina,Lyssenko,Il'In,Strelkova,Timofeeva,Peregudov,North
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experimental part
p. 1981 - 1988
(2009/12/23)
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- Synthesis and properties of novel chiral-amine-functionalized ionic liquids
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A novel class of chiral-amine-functionalized ionic liquids (CAFILs) has been synthesized efficiently from natural amino acids, and their structures have been determined by spectroscopic analysis and low temperature X-ray diffraction analysis. The CAFILs have been characterized by physical properties such as melting point, glass transition temperature, thermal degradation and specific rotation. NMR measurements indicate that the CAFILs may be promising alternatives in the field of chiral discrimination.
- Luo, Shu-Ping,Xu, Dan-Qian,Yue, Hua-Dong,Wang, Li-Ping,Yang, Wen-Long,Xu, Zhen-Yuan
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p. 2028 - 2033
(2007/10/03)
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- DABCO catalyzed reaction of various nucleophiles with activated alkynes leading to the formation of alkenoic acid esters, 1,4-dioxane, morpholine, and piperazinone derivatives
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The reaction of acids, alcohols, acylamides, 1,2-diols, 1,2-diamines or amino alcohols with activated alkynes catalyzed by 1,4-diazabicyclo[2.2.2]octane (DABCO) was systematically investigated. A series of unsaturated alkenoic acid esters or heterocycles were formed in the reaction of monobasic or dibasic nucleophiles in excellent yields, respectively.
- Fan, Ming-Jin,Li, Gao-Qiang,Liang, Yong-Min
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p. 6782 - 6791
(2007/10/03)
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- Properties and Reactions of Substituted 1,2-Thiazetidine 1,1-Dioxides: Chiral Mono- and Bicyclic 1,2-Thiazetidine 1,1-Dioxides from α-Amino Acids
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New chiral mono- and bicyclic β-sultams, valuable building blocks for drug synthesis, have been prepared from L-Ala, L-Val, L-Leu, L-Ile, L-Phe, L-Cys, L-Ser, L-Thr, and D-penicillamine by transformation of the COOH group into a methylsulfonyl chloride function, followed by cyclization under basic conditions. Selected properties, derivatives, and reactions of the β-sultams are described.
- Meinzer, Alexandra,Breckel, Andrea,Thaher, Bassam Abu,Manicone, Nico,Otto, Hans-Hartwig
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- New chiral ammonium salt hosts derived from amino acids: Very efficient optical resolution of 2,2′-dihydroxy-1,1′-binaphthyl by complexation with these host compounds
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Chiral ammonium salt hosts are prepared from amino acids by transformation of their NH2 and CO2H groups into Me3N+Br- and CH2OH groups, respectively, via three simple reaction steps; by complexation with these hosts, 2,2′-dihydroxy-1,1′-binaphthyl is resolved very efficiently.
- Toda, Fumio,Tanaka, Kenya
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p. 1087 - 1088
(2007/10/03)
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- Unusual reactivity of zinc borohydride conversion of amino acids to amino alcohols
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Zinc borohydride reduces amino acids with only stoichiometric amounts of hydride to the corresponding chiral alcohols in excellent yields in the absence of any Lewis acid.
- Narasimhan,Madhavan,Ganeshwar Prasad
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p. 703 - 706
(2007/10/03)
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- 9. Les β-cetonitriles groupes protecteurs de la fonction amine. Preparation d'amino-alcools
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β-Ketonitrile-Derived Protecting Groups of the Amino Function.Synthesis of Amino Alcohols.The amino group of natural L-amino acid esters is protected by condensation with 2-oxocyclopentanenitrile (1) or 2-formyl-2-phenylacetonitrile (10).Only the ester group of the formed cyanoenamino esters 2 and 11 reacts with nucleophilic reagents such as organometallics (RMgX, RLi), borohydrides, or metal amides, whereas the cyanoenamino group is unchanged (Schemes 1 and 2).Cyanoenamino alcohols obtained by reduction of cyanoenamino esters 2 are hydrolyzed under acidic conditions to amino alcohols with retention of the configuration of the starting amino acid.This sequence of reactions allows to prepare derivatives of L-tyrosinol from (-)-L-tyrosine (see, e.g., Scheme 4).Cyanoenamino esters 11 are readily methylated at the N-atom to give N-methylated cyanoenamino esters (Scheme 3).This property is exploited on the way of multistep procedure to obtain N-methylated amino alcohols homologous to natural (-)-(1R,2S)-ephedrine.
- Abarbri, Mohamed,Guignard, Alain,Lamant, Maurice
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p. 109 - 121
(2007/10/02)
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- DIMERISATION DE DIENES CONJUGUES A L'AIDE DE COMPLEXES DU NICKEL EN PRESENCE DE LIGANDS DE TYPE AMINOPHOSPHINITE ETUDE D'OPTIMISATION
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New chiral aminophosphinite ligands are readily prepared and their behaviour as homogeneous catalysts was investigated in the linear dimerization of butadiene and isoprene.This latter reaction has been optimised using experimental research methodology, leading to a conversion rate above 50percent.
- Masotti, Henriette,Pfeiffer, Gilbert,Siv, Chhan,Courbis, Pierre,Sergent, Michelle,Phan TAN LUU, Roger
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- Asymmetric Synthesis Using Chirally Modified Borohydrides. Part 1. Enantioselective Reduction of Aromatic Ketones with the Reagent Prepared from Borane and (S)-Valinol
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The asymmetric reduction of aromatic ketones with the reagents prepared from borane and chiral aminoalcohols was studied under various conditions.The ratio of borane to (S)-valinol was found to be optimum at 2-3:1, when up to 65-73percent selectivity was obtained in the reduction of n-propyl phenyl ketone.The amino-alkoxy-amine-boranes (2) and/or (3) were tentatively proposed as the reaction species responsible for asymmetric induction.
- Itsuno, Shinichi,Hirao, Akira,Nakahama, Seiichi,Yamazaki, Noboru
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p. 1673 - 1676
(2007/10/02)
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