- Synthesis and application of N-3,5-dinitrobenzoyl and C3 symmetric diastereomeric chiral stationary phases
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Three diastereomeric chiral compounds, namely, (R,R)-(+)-2-amino-1,2-diphenylethanol, (1S,2R)-(+)-2-amino-1,2-diphenylethanol, and (1R,2R)-(+)-1,2-diphenylethylenediamine were used as starting materials for preparing three N-3,5-dinitrobenzoyl derivative
- Yu, Jeong Jae,Ryoo, Jae Jeong
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p. 587 - 596
(2022/01/20)
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- Irradiation-Wavelength Directing Circularly Polarized Luminescence in Self-Organized Helical Superstructures Enabled by Hydrogen-Bonded Chiral Fluorescent Molecular Switches
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Two light-driven chiral fluorescent molecular switches, (R,S,R)-switch 1 and (R,S,R)-switch 2, are prepared by means of hydrogen-bonded (H-bonded) assembly of a photoresponsive (S) chiral fluorescent molecule, respectively with a cyano substitution at different positions as an H-bond acceptor and an opposite (R) chiral molecule as an H-bond donor. The resulting two switches exhibit tunable and reversible Z/E photoisomerization irradiated with 450 nm blue and 365 nm UV light. When doped into an achiral liquid crystal, both switches are found to be able to form a CPL tunable luminescent helical superstructure. In contrast to the tunable CPL characteristics of the system incorporating switch 2, exposure of the system incorporating switch 1 to 365 nm and 450 nm radiation can lead to controllable different photostationary CPL behavior, including switching-off and polarization inversion. In addition, optical information coding is demonstrated using the system containing switch 1.
- He, Yanrong,Zhang, Shu,Bisoyi, Hari Krishna,Qiao, Jinghui,Chen, Hong,Gao, JingJing,Guo, Jinbao,Li, Quan
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supporting information
p. 27158 - 27163
(2021/10/25)
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- Resolution of Vaulted Biaryl Ligands via Borate Esters of Quinine and Quinidine
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Given the sudden and unexplained rise in the cost of (+)- A nd (-)-sparteine, an alternative method for the resolution of vaulted biaryls has been developed. This method involves the reaction of a racemic vaulted biaryl ligand with one equivalent of BH3·SMe2 and one equivalent of either quinine or quinidine. A precipitate then forms from the resulting mixture of diastereomeric borates as a result of differential solubilities. Hydrolysis of the precipitate then liberates the (S)-ligand in the case of quinine and the (R)-ligand in the case of quinidine, both with >99% ee. This method has been applied to 16 different vaulted biaryl ligands, including 10 whose preparation is described here for the first time. In addition, proof of principle has been demonstrated for the dynamic thermodynamic resolution of the vaulted biaryl ligands with this method in combination with a nonchiral copper(II) complex that can racemize the ligand.
- Cagnon, Brian R.,Mohammadlou, Aliakbar,Wulff, William D.,Yin, Xiaopeng,Zheng, Li
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p. 10432 - 10450
(2020/09/23)
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- Novel chiral stationary phases based on 3,5-dimethyl phenylcarbamoylated β-cyclodextrin combining cinchona alkaloid moiety
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Novel chiral selectors based on 3,5-dimethyl phenylcarbamoylated β-cyclodextrin connecting quinine (QN) or quinidine (QD) moiety were synthesized and immobilized on silica gel. Their chromatographic performances were investigated by comparing to the 3,5-dimethyl phenylcarbamoylated β-cyclodextrin (β-CD) chiral stationary phase (CSP) and 9-O-(tert-butylcarbamoyl)-QN-based CSP (QN-AX). Fmoc-protected amino acids, chiral drug cloprostenol (which has been successfully employed in veterinary medicine), and neutral chiral analytes were evaluated on CSPs, and the results showed that the novel CSPs characterized as both enantioseparation capabilities of CD-based CSP and QN/QD-based CSPs have broader application range than β-CD-based CSP or QN/QD-based CSPs. It was found that QN/QD moieties play a dominant role in the overall enantioseparation process of Fmoc-amino acids accompanied by the synergistic effect of β-CD moiety, which lead to the different enantioseparation of β-CD-QN-based CSP and β-CD-QD-based CSP. Furthermore, new CSPs retain extraordinary enantioseparation of cyclodextrin-based CSP for some neutral analytes on normal phase and even exhibit better enantioseparation than the corresponding β-CD-based CSP for certain samples.
- Zhu, Lunan,Zhu, Junchen,Sun, Xiaotong,Wu, Yaling,Wang, Huiying,Cheng, Lingping,Shen, Jiawei,Ke, Yanxiong
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p. 1080 - 1090
(2020/05/25)
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- Enantioselective iron/bisquinolyldiamine ligand‐catalyzed oxidative coupling reaction of 2‐naphthols
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An iron‐catalyzed asymmetric oxidative homo‐coupling of 2‐naphthols for the synthesis of 1,1′‐Bi‐2‐naphthol (BINOL) derivatives is reported. The coupling reaction provides enantioenriched BINOLs in good yields (up to 99%) and moderate enantioselectivities (up to 81:19 er) using an iron‐complex generated in situ from Fe(ClO4)2 and a bisquinolyldiamine ligand [(1R,2R)‐N1,N2‐di(quinolin‐8‐yl)cyclohexane‐1,2‐diamine, L1]. A number of ligands (L2–L8) and the analogs of L1, with various substituents and chiral backbones, were synthesized and examined in the oxidative coupling reactions.
- Liu, Wen-Bo,Usman, Muhammad,Wu, Lin-Yang
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- Ruthenium-Catalyzed Cross-Selective Asymmetric Oxidative Coupling of Arenols
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(Aqua)ruthenium(salen) complex 1c achieved good to high chemo- A nd enantioselective oxidative cross-coupling of arenols. The catalytic system can be used to selectively produce C1-symmetric bis(arenol)s from the combination of C3- A nd C7-substituted 2-naphthols or phenols even when there is no significant difference in oxidation potential between the cross-coupling partners. This unique cross-selectivity is dominated by steric rather than electronic effects of the arenols and can be controlled by chemoselective single-electron oxidation and oxidative carbon-carbon bond formation.
- Hayashi, Hiroki,Kim, Chungsik,Uchida, Tatsuya,Ueno, Takamasa
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supporting information
(2020/02/26)
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- Novel π-expanded chrysene-based axially chiral molecules: 1,1′-bichrysene-2,2′-diols and thiophene analogs
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1,1′-Bichrysene-2,2′-diol and its thiophene analogs, 6,6′-biphenanthro-[1,2-b]thiophene-7,7′-diols, as a series of novel π-expanded chrysene-/phenanthro[1,2-b]thiophene-based axially chiral molecules are synthesized from 1,1′-bi-2-naphthols with key steps
- An, Shujie,Liu, Qiancai,Ma, Li,Tang, Guofeng,Zhong, Yaling
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p. 641 - 645
(2020/05/25)
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- Enantioselective Hydroamination of Alkenes with Sulfonamides Enabled by Proton-Coupled Electron Transfer
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An enantioselective, radical-based method for the intramolecular hydroamination of alkenes with sulfonamides is reported. These reactions are proposed to proceed via N-centered radicals formed by proton-coupled electron transfer (PCET) activation of sulfonamide N-H bonds. Noncovalent interactions between the neutral sulfonamidyl radical and a chiral phosphoric acid generated in the PCET event are hypothesized to serve as the basis for asymmetric induction in a subsequent C-N bond forming step, achieving selectivities of up to 98:2 er. These results offer further support for the ability of noncovalent interactions to enforce stereoselectivity in reactions of transient and highly reactive open-shell intermediates.
- Demaerel, Joachim,Graff, David E.,Knowles, Robert R.,Roos, Casey B.
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supporting information
p. 5974 - 5979
(2020/04/27)
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- Three-State Switchable Chiral Stationary Phase Based on Helicity Control of an Optically Active Poly(phenylacetylene) Derivative by Using Metal Cations in the Solid State
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An unprecedented three-state switchable chiral stationary phase (CSP) for high-performance liquid chromatography (HPLC) was developed using a helical poly(phenylacetylene) bearing a chiral (R)-α-methoxyphenylacetic acid residue as the pendant (poly-1). The left- and right-handed helical conformations were induced in poly-1-based CSP upon coordination with a catalytic amount of soluble sodium and cesium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate salts (MBArF), respectively, which are soluble in the HPLC conditions [hexane-2-propanol (95:5, v/v)]. The switch between the two different helical states of poly-1 can be easily achieved by rinsing the poly-1-based CSP with MeOH and the subsequent addition of the proper MBArF salt. Using this dynamic helical CSP, we demonstrate how changes on the orientation of the secondary structure of a chiral polymer (right-handed, left-handed, and racemic helices) can alter and even invert the elution order of the enantiomers. This study was done without adding chiral additives or changing the mobile phase, which could produce changes on the retention times and make it more difficult to determine the role of the secondary structure during the chiral recognition process.
- Hirose, Daisuke,Isobe, Asahi,Qui?oá, Emilio,Freire, Félix,Maeda, Katsuhiro
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- Three-State Switchable Chiral Stationary Phase Based on Helicity Control of an Optically Active Poly(phenylacetylene) Derivative by Using Metal Cations in the Solid State
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An unprecedented three-state switchable chiral stationary phase (CSP) for high-performance liquid chromatography (HPLC) was developed using a helical poly(phenylacetylene) bearing a chiral (R)-α-methoxyphenylacetic acid residue as the pendant (poly-1). The left- and right-handed helical conformations were induced in poly-1-based CSP upon coordination with a catalytic amount of soluble sodium and cesium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate salts (MBArF), respectively, which are soluble in the HPLC conditions [hexane-2-propanol (95:5, v/v)]. The switch between the two different helical states of poly-1 can be easily achieved by rinsing the poly-1-based CSP with MeOH and the subsequent addition of the proper MBArF salt. Using this dynamic helical CSP, we demonstrate how changes on the orientation of the secondary structure of a chiral polymer (right-handed, left-handed, and racemic helices) can alter and even invert the elution order of the enantiomers. This study was done without adding chiral additives or changing the mobile phase, which could produce changes on the retention times and make it more difficult to determine the role of the secondary structure during the chiral recognition process.
- Hirose, Daisuke,Isobe, Asahi,Qui?oá, Emilio,Freire, Félix,Maeda, Katsuhiro
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p. 8592 - 8598
(2019/06/13)
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- An enantioselective oxidative coupling reaction of 2-naphthol derivatives catalyzed by chiral diphosphine oxide-iron(ii) complexes
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An enantioselective oxidative coupling of 2-naphthol derivatives is developed with the use of chiral Fe(ii)-diphosphine oxide complexes. Optically active 1,1-bi-2-naphthol derivatives can be synthesized in high yields when a 2?:?1 complex of (S)-xylyl-iPrO-BIPHEP-oxide and Fe(OTf)2 is used in the presence of t-butyl hydroperoxide as an oxidant. The non-linear effect, X-ray crystal structure and ESI-MS suggest that a 2?:?1 complex of (S)-xylyl-iPrO-BIPHEP-oxide and Fe(OTf)2 is a pre-catalyst for a Fe(iii)/Fe(iv) redox cycle.
- Horibe, Takahiro,Nakagawa, Keita,Hazeyama, Takashi,Takeda, Kazuki,Ishihara, Kazuaki
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supporting information
p. 13677 - 13680
(2019/11/19)
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- Facile synthesis of homochiral compounds integrating circularly polarized luminescence and two-photon excited fluorescence
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A pair of novel chiral one-dimensional compounds with the general formula [Cd(NO3)2L2]·THF (where L is R- or S-2,2′-bis(methoxymethoxy)-6,6′-bis(4-pyridyl)-1,1′-binaphthyl) for the first time show circularly polarized luminescence, two-photon excited fluorescence, and second harmonic generation activity.
- Deng, Wen-Ting,Qu, Hang,Huang, Zhe-Yu,Shi, Lin,Tang, Zhi-Yong,Cao, Xiao-Yu,Tao, Jun
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supporting information
p. 2210 - 2213
(2019/02/20)
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- Synthesis of new C3 symmetric amino acid- and aminoalcohol-containing chiral stationary phases and application to HPLC enantioseparations
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We recently reported a new C3-symmetric (R)-phenylglycinol N-1,3,5-benzenetricarboxylic acid-derived chiral high-performance liquid chromatography (HPLC) stationary phase (CSP 1) that demonstrated better results as compared to a previously described N-3,5-dintrobenzoyl (DNB) (R)-phenylglycinol-derived CSP. Over a decade ago, (S)-leucinol, (R)-phenylglycine, and (S)-leucine derivatives were used as the starting materials of 3,5-DNB-based Pirkle-type CSPs for chiral separation. In this study, three new C3-symmetric CSPs (CSP 2, 3, and 4) were prepared by combining the ideas and results mentioned above. Here we describe the synthetic procedures and applications of the new C3-symmetric CSPs (CSP 2–CSP 4).
- Yu, Jeongjae,Armstrong, Daniel W.,Ryoo, Jae Jeong
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-
- Design and Enantioresolution of Homochiral Fe(II)-Pd(II) Coordination Cages from Stereolabile Metalloligands: Stereochemical Stability and Enantioselective Separation
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The stereochemistry of chiral-at-metal complexes is much more abundant, albeit complicated, than chiral-at-carbon compounds, but how to make use of stereolabile metal-centers remains a formidable challenge due to the highly versatile coordination geometry of metal ions and racemization/epimerization problem. We demonstrate herein a stepwise assembly of configurationally stable [Pd6(FeL3)8]28+ (Δ/-MOCs-42) homochiral octahedral cages from unstable D3-symmetry tris-chelate-Fe type metalloligands via strong face-directed stereochemical coupling and facile chiral-induced resolution processes based on stereodifferentiating host-guest dynamics. Kinetic studies reveal that the dissociation rate of MOC-42 cages is 100-fold slower than that of Fe-metalloligands and the racemization is effectively inhibited, making the cages retain their chirality over extended periods of time (>5 months) at room temperature. Recyclable enantioseparation of atropisomeric compounds has been successfully achieved, giving up to 88% ee.
- Hou, Ya-Jun,Wu, Kai,Wei, Zhang-Wen,Li, Kang,Lu, Yu-Lin,Zhu, Cheng-Yi,Wang, Jing-Si,Pan, Mei,Jiang, Ji-Jun,Li, Guang-Qin,Su, Cheng-Yong
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supporting information
p. 18183 - 18191
(2019/01/09)
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- Click-binol-phosphoric acid catalysts in intramolecular enantioselective oxidative C[sbnd]H-bond functionalization
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Counteranion-catalysis represents an appealing but challenging approach for the development of enantioselective oxidative C[sbnd]H bond functionalization reactions. In this work, a new family of 3,3′-triazolyl BINOL-derived phosphoric acids was synthesized and employed in the intramolecular asymmetric C[sbnd]H bond functionalization of N-aryl substituted tetrahydroisoquinolines. As previously reported with related structures, the presence of the triazole groups on the catalysts was key to attain enantioselectivity. Our study also shows the importance of choosing the appropriate regioisomeric triazole groups at the BINOL backbone to achieve a more efficient chirality transfer. Moderate enantiomeric ratios were obtained with the N-benzamide substrates, whereas the change of the nature of the nucleophile fragment was translated to a dramatic loss of the enantioselectivity. Therefore, it can be foreseen that there is a need for designing further superior catalyst structures to develop future counter-anion organocatalyzed asymmetric C[sbnd]H bond functionalization reactions.
- Stockerl, Sebastian,Gutiérrez, Daniel,García Manche?o, Olga
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p. 572 - 585
(2016/12/16)
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- Chiral separation on various modified amino alcohol-derived HPLC chiral stationary phases
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3,5-Dinitrobenzoyl chloride was previously used for the preparation of (R)-phenylglycinol- and (S)-leucinol-derived chiral stationary phases. In this study, 3,5-bis(trifluoromethyl)benzoyl chloride, 2-furoyl chloride, 2-theonyl chloride, 10,11-dihydro-5H-dibenzo[b,f]azepine-5-carbonyl chloride, diphenylcarbamoyl chloride, and 1-adamantanecarbonyl chloride were used to prepare six new phenylglycinol-derived chiral stationary phases (CSPs) and five new leucinol-derived CSPs. Using these 11 CSPs, chiral separation of nine π-acidic amino acid derivatives and five π-basic compounds was performed, and the separation results were compared. An adamantyl-derived CSP showed good separation.
- Yu, Jeongjae,Lee, Jung Mi,Ryoo, Jae Jeong
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p. 276 - 281
(2016/03/19)
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- Cofactor-Controlled Chirality of Tropoisomeric Ligand
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A new tropos ligand with an integrated anion receptor site has been prepared. Chiral carboxylate and phosphate anions that bind in the anion receptor unit proved capable of stabilizing chiral conformations of the achiral flexible bidentate biaryl phosphite ligand, as shown by variable temperature 1H and 31P NMR spectroscopical studies of palladium(0) olefin complexes. Palladium allyl complexes of the supramolecular ligand-chiral cofactor assemblies catalyzed asymmetric allylic substitutions of rac-(E)-1,3-diphenyl-2-propenyl carbonate and rac-3-cyclohexenyl carbonate with malonate and benzylamine as nucleophiles to provide nonracemic products. Although moderate enantioselectivities were observed, (ee:s up to 66%), the results confirm the ability of the anionic guests to affect the conformation of the ligand.
- Théveau, Laure,Bellini, Rosalba,Dydio, Pawe?,Szabo, Zoltan,Van Der Werf, Angela,Afshin Sander, Robin,Reek, Joost N. H.,Moberg, Christina
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supporting information
p. 1956 - 1963
(2016/07/06)
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- Macromolecular helicity induction and memory in a poly(biphenylylacetylene) bearing an ester group and its application to a chiral stationary phase for high-performance liquid chromatography
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An optically inactive poly(biphenylylacetylene) bearing an ester group at the 4′-position of the pendants formed a preferred-handed helical conformation and biased axial chirality in the pendants through a noncovalent interaction with a chiral alcohol, both of which were retained (memorized) even after removal of the chiral alcohol. The chiral stationary phase for high-performance liquid chromatography, prepared by coating the polymer with macromolecular helicity memory on silica gel, showed good chiral recognition ability towards various racemates.
- Ishidate, Ryoma,Shimomura, Kouhei,Ikai, Tomoyuki,Kanoh, Shigeyoshi,Maeda, Katsuhiro
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p. 946 - 948
(2015/08/24)
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- Liquid crystallinity-embodied imidazolium-based ionic liquids and their chiral mesophases induced by axially chiral tetra-substituted binaphthyl derivatives
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We synthesised novel imidazolium-based ionic liquids with thermotropic liquid crystallinity by introducing phenylcyclohexyl and/or cyanobiphenyl mesogenic cores and hexyl or dodecyl methine chains into both sites of imidazolium moieties facing bromide anions. The liquid crystalline ionic liquids (LCILs) thus synthesised showed a nematic or smectic mesophase in both the heating and cooling processes, indicating the enantiotropic nature of the liquid crystallinity. The LCILs bearing the same types of double mesogenic cores [LCIL-2] showed a smectic A phase in the temperature range from 115 to 175 °C, whereas the LCILs with different types of double mesogenic cores [LCIL-3 and LCIL-4] showed nematic phases in the temperature ranges from 58 to 88 °C and 43 to 95 °C, respectively. The axially chiral binaphthyl derivatives substituted by LC groups at the 2,2′, 6,6′ positions of the binaphthyl rings were synthesised and used as chiral dopants with large helical twisting powers. The mixtures of the LCILs and the (R)- and (S)-binaphthyl derivatives exhibited induced chiral nematic phases with right-and left-handed helical senses, respectively. The ionic conductivities of the LCILs were evaluated to be 10-7-10-4 S cm-1, depending on the isotropic, LC, and crystal phases. The temperature dependence of the ionic conductivities indicates that the LCILs can be regarded as semi-conducting materials. The LCILs might be used as anisotropic ionic conductors and can even serve as anisotropic solvents and electrolytes in electrochemical polymerisations. This journal is
- Ahn, Sangbum,Yamakawa, Shohei,Akagi, Kazuo
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supporting information
p. 3960 - 3970
(2015/04/27)
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- Helical carbon and graphite films prepared from helical poly(3,4-ethylenedioxythiophene) films synthesized by electrochemical polymerization in chiral nematic liquid crystals
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Helical carbon and graphite films from helical poly(3,4- ethylenedioxythiophene) (H-PEDOT) films synthesized through electrochemical polymerization in a chiral nematic liquid-crystal (N-LC) field are prepared. The microscope investigations showed that the
- Matsushita, Satoshi,Yan, Bairu,Yamamoto, Shinsuke,Jeong, Yong Soo,Akagi, Kazuo
-
supporting information
p. 1659 - 1663
(2014/03/21)
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- Relationships between main-chain chirality and photophysical properties in chiral conjugated polymers
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A series of R- and S-binaphthyl-containing polyfluorenes, bearing different contents and types of axial chirality in the main chain, have been synthesized through Suzuki polycondensation to investigate the influence of the covalently incorporated chirality on the photophysical properties of chiral conjugated polymers. The experimental measurements obtained by UV-Vis and photoluminescence (PL) spectroscopy, cyclic voltammetry, and circular dichroism spectroscopy reveal that the chiral copolymers possess high thermostability, high luminescence efficiency, reversible electrochemical properties, and intrachain transferred dichroism. Surprisingly, the R-chiral polymers exhibit better spectral thermostability, stronger suppressing ability upon the β-phase formation of the main-chain, and higher PL quantum efficiency than S-chiral polymers in solid films. The theoretical insights obtained by either ab initio density functional theory (DFT) calculations or molecular dynamics (MD) simulations suggest that these differences probably resulted from the more planar chain conformation of S-chiral polymers, which leads to stronger interchain interaction and an increased tendency to form inefficient and unstable excimers or quenchers. The different effects of enantiomers on the photophysical properties of chiral conjugated polymers may provide an import update in the understanding of chiro-optics. This journal is the Partner Organisations 2014.
- Zheng, Chao,An, Zhongfu,Nakai, Yosuke,Tsuboi, Taiju,Wang, Yang,Shi, Huifang,Chen, Runfeng,Li, Huanhuan,Ji, Yimu,Li, Junfeng,Huang, Wei
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p. 7336 - 7347
(2014/11/08)
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- Rationally designed axially chiral diarylethene switches with high helical twisting power
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Three rationally designed axially chiral diaryle-thene switches were synthesized and their application as chiral dopants for phototunable cholesteric liquid crystal devices was investigated. Design of these molecules was based on the combination of photoc
- Li, Yannian,Wang, Mengfei,Wang, Hao,Urbas, Augustine,Li, Quan
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p. 16286 - 16292
(2015/02/19)
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- A coumarin-based chiral fluorescence sensor for the highly enantioselective recognition of phenylalaninol
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A chiral host L1 incorporating (S)-BINOL and substituted coumarin moieties was synthesized via a nucleophilic addition-elimination reaction, and ligand L2 could be obtained by the reduction reaction of the imine-based L1 with NaBH 4. The fluorescence responses of chiral compounds L1 and L2 on (l)-/(d)-phenylalaninol were investigated by fluorescence spectra. The fluorescence intensity of L1 in cooperation with (l)-/(d)-phenylalaninol shows a gradual enhancement upon addition of (l)-/(d)-phenylalaninol and keeps a nearly linear correlation with the concentration molar ratios from 1:10 to 1:180. Stoichiometries and association constants of L1 with (l)-/(d)-phenylalaninol were calculated. The results indicate that chiral sensor L1 can exhibit a remarkable "turn-on" fluorescence enhancement response and excellent enantioselective behaviour for (l)-phenylalaninol by direct visual observation at low concentration, and the value of the enantiomeric fluorescence difference ratio (ef) is 3.07. On the contrary, no obvious fluorescence response and enantioselective recognition effect can be detected for L2 towards either (l)-/(d)-phenylalaninol.
- Jiao, Jiemin,Liu, Xunhua,Mao, Xuerong,Li, Junfeng,Cheng, Yixiang,Zhu, Chengjian
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p. 317 - 322
(2013/02/25)
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- Solution-phase synthesis and evaluation of tetraproline chiral stationary phases
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A protocol was developed for the solution-phase synthesis of multigram amounts of two 9-fluorenylmethoxycarbonyl (Fmoc)-protected tetraproline peptides. These tetraproline peptides were then attached to amino derivatized silica gel. The replacement of the Fmoc group with the trimethylacetyl group lead to two tetraproline chiral stationary phases (CSPs). A comparison of the chromatographic behavior of these two solution-phase-synthesized tetraproline CSPs with that prepared by stepwise solid-phase synthesis revealed that all three had similar chromatographic performance for resolving 53 model analytes. This suggests that the solution-phase synthesis of oligoprolines, which allows for the specific benefits of good batch reproducibility, selector homogeneity, and possibly low cost, is a feasible alternative to the solid-phase synthesis of oligoproline CSPs. Copyright
- Dai, Zhi,Ye, Guozhong,Pittman Jr., Charles U.,Li, Tingyu
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experimental part
p. 329 - 338
(2012/05/20)
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- Chiral nematic organo-siloxane oligopodes based on an axially chiral binaphthalene core
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The synthesis of a novel class of organosiloxane oligopodes, based on an axially chiral binaphthalene core is described and their mesogenic properties are fully characterised. The Royal Society of Chemistry 2012.
- Schubert, Christopher P. J.,Tamba, M. Gabriela,Mehl, Georg H.
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supporting information; experimental part
p. 6851 - 6853
(2012/07/31)
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- Clarification of a misconception in the BINOL-based fluorescent sensors: Synthesis and study of major-groove BINOL-amino alcohols
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The major-groove BINOL-amino alcohol (S)-6 shows greatly enhanced fluorescence over the minor-groove one (S)-3. The study of a series of the major-groove BINOL-amino alcohol compounds demonstrates that the commonly accepted acid inhibition of the PET fluo
- Liu, Hai-Lin,Zhao, Qiao-Ling,Hou, Xue-Long,Pu, Lin
-
scheme or table
p. 3646 - 3648
(2011/05/04)
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- A chiral perazamacrocyclic fluorescent sensor for cascade recognition of Cu(II) and the unmodified α-amino acids in protic solutions
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A novel chiral Perazamacrocyclic fluorescent sensor (1) was designed and synthesized. It can serve as a fluorescent turn-off sensor with high selectivity toward Cu(II) among 14 metal ions. Furthermore, though 1 exhibits no enantioselectivity, after adding Cu(II), the in situ generated Cu(II)-containing complex of 1 (Cu(II)-1) can exhibit remarkable fluorescent enhancement responses and considerable enantioselectivities toward unmodified α-amino acids in protic solutions via a ligand displacement mechanism; i.e. a cascade recognition of Cu(II) and unmodified α-amino acids has been achieved.
- Yang, Xia,Liu, Xuechao,Shen, Kang,Zhu, Chengjian,Cheng, Yixiang
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supporting information; experimental part
p. 3510 - 3513
(2011/09/15)
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- A fluorescence sensor based on chiral polymer for highly enantioselective recognition of phenylalaninol
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The chiral polymer P-1 incorporating (S)-2,2′-binaphthol (BINOL) and (S)-2,2′-binaphthyldiamine (BINAM) moieties in the main chain of the polymer backbone was synthesized by the polymerization of (S)-6,6′- dibutyl-3,3′-diformyl-2,2′-binaphthol (S-M-1) with (S)-2,2′-binaphthyldiamine (S-M-2) via nucleophilic addition-elimination reaction, and the chiral polymer P-2 could be obtained by the reduction reaction of P-1 with NaBH4. The fluorescence intensity of the chiral polymer P-1 exhibits gradual enhancement upon addition of (d)- or (l)-phenylalaninol and keeps nearly a linear correlation with the concentration molar ratios of (d)- or (l)-phenylalaninol. The value of enantiomeric fluorescence difference ratio (ef) is 6.85 for the chiral polymer on (d)-phenylalaninol. On the contrary, the chiral polymer P-2 shows no obvious fluorescence response toward either (d)- or (l)-phenylalaninol.
- Meng, Jie,Wei, Guo,Huang, Xiaobo,Dong, Yu,Cheng, Yixiang,Zhu, Chengjian
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scheme or table
p. 363 - 367
(2012/01/13)
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- A polymer based fluorescent sensor for Zn2+ detection and its application for constructing logic gates
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A polymer-based fluorescent sensor was synthesized by polymerization of (S)-6,6′-dibutyl-3,3′-(di-5-salicylde-ethynyl)-2, 2′-binaphthol (M-1) with (R,R)-1,2-diaminocyclohexane (M-2) via nucleophilic addition-elimination reaction. The responsive optical pr
- Dong, Yu,Wu, Yuanzhao,Jiang, Xiaoxiang,Huang, Xiaobo,Cheng, Yixiang,Zhu, Chengjian
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scheme or table
p. 5811 - 5816
(2012/03/26)
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- COMPOSITIONS AND METHODS FOR CYCLOFRUCTANS AS SEPARATION AGENTS
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The present invention relates to derivatized cyclofructan compounds, compositions comprising derivatized cyclofructan compounds, and methods of using compositions comprising derivatized cyclofructan compounds for chromatographic separations of chemical species, including enantiomers. Said compositions may comprise a solid support and/or polymers comprising derivatized cyclofructan compounds.
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Page/Page column 45-49; 56
(2010/12/31)
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- Enantioenriched synthesis of C 1-symmetric BINOLs: Iron-catalyzed cross-coupling of 2-naphthols and some mechanistic insight
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Highly enantioselective aerobic oxidative cross-coupling of 2-naphthols with broad substrate scope was achieved using an iron(salan) complex as the catalyst. Enantiomeric excesses of the products ranged from 87 to 95%. The scope of the cross-coupling reac
- Egami, Hiromichi,Matsumoto, Kenji,Oguma, Takuya,Kunisu, Takashi,Katsuki, Tsutomu
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supporting information; experimental part
p. 13633 - 13635
(2010/11/17)
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- Metal-organic frameworks with designed chiral recognition sites
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Linking struts containing Cram-like bisbinaphthyl[22]crown-6 with Zn 4O(CO2)6 joints affords metal-organic frameworks with chiral recognition sites that are highly designed, ordered and placed in a precise manner throughou
- Valente, Cory,Choi, Eunwoo,Belowich, Matthew E.,Doonan, Christian J.,Li, Qiaowei,Gasa, Travis B.,Botros, Youssry Y.,Yaghi, Omar M.,Stoddart, J. Fraser
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supporting information; experimental part
p. 4911 - 4913
(2010/08/07)
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- Development of new HPLC chiral stationary phases based on native and derivatized cyclofructans
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An unusual class of chiral selectors, cyclofructans, is introduced for the first time as bonded chiral stationary phases. Compared to native cyclofructans (CFs), which have rather limited capabilities as chiral selectors, aliphatic-and aromatic-functionalized CF6s possess unique and very different enantiomeric selectivities. Indeed, they are shown to separate a very broad range of racemic compounds. In particular, aliphatic-derivatized CF6s with a low substitution degree baseline separate all tested chiral primary amines. It appears that partial derivatization on the CF6 molecule disrupts the molecular internal hydrogen bonding, thereby making the core of the molecule more accessible. In contrast, highly aromaticfunctionalized CF6 stationary phases lose most of the enantioselective capabilities toward primary amines, however they gain broad selectivity for most other types of analytes. This class of stationary phases also demonstrates high "loadability" and therefore has great potential for preparative separations. The variations in enantiomeric selectivity often can be correlated with distinct structural features of the selector. The separations occur predominantly in the presence of organic solvents.
- Sun, Ping,Wang, Chunlei,Breitbach, Zachary S.,Zhang, Ying,Armstrong, Daniel W.
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experimental part
p. 10215 - 10226
(2010/05/01)
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- Synthesis and helicate formation of a new family of binol-based bis(bipyridine) ligands
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A new family of BINOL-based bis(bipyridine) ligands 1-3 (BINOL = 2,2 -dihydroxy-1,1 -binaphthyl) was prepared in enantiomerically pure form. Whereas the coordination of zinc(ll) ions to these ligands did not result in the selective formation of a specific metallosupramolecular aggregate,1 -3 were found to undergo highly diastereoselective self-assembly to D 2-symmetric dinuclear double-stranded helicates upon coordin ation to silver(l) and copper(l) ions and to D3-symmetric dinuclear triple-stranded helicates upon coordination to iron(ll) as demonstrated by mass spectrometry and by NMR and CD spectroscopy in combination with quantum chemical calculations.
- Bunzen, Jens,Bruhn, Torsten,Bringmann, Gerhard,Luetzen, Arne
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scheme or table
p. 3621 - 3630
(2009/08/14)
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- Dual activation in oxidative coupling of 2-naphthols catalyzed by chiral dinuclear vanadium complexes
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An efficient enantioselective oxidative coupling of 2-naphthol derivatives based on a concept of dual activation catalysis is realized. A chiral dinuclear vanadium(IV) complex (Ra,S,S)-1e possessing (S)-tert-leucine moieties at the 3,3′-positions of the (R)-binaphthyl skeleton was developed, which was found to promote the oxidative coupling of 2-naphthol to afford (S)-BINOL with 91% ee. To verify the dual activation mechanism, mononuclear vanadium(IV) complex (S)-8 was also prepared. Kinetic analysis revealed that the reaction rate of oxidative coupling of 2-naphthol promoted by (Ra,S,S)-1e is 48.3 times faster than that of (S)-8. The two vanadium metals in the chiral complex activate two molecules of 2-naphthol simultaneously in an intramolecular manner coupling reaction, achieving a high reaction rate with high enantiocontrol. Reaction mechanisms of the oxidative coupling reaction promoted by either vanadium(IV) or vanadium(V) complexes are also described.
- Takizawa, Shinobu,Katayama, Tomomi,Somei, Hidenori,Asano, Yasuaki,Yoshida, Tomokazu,Kameyama, Chiaki,Rajesh, Doss,Onitsuka, Kiyotaka,Suzuki, Takeyuki,Mikami, Masafumi,Yamataka, Hiroshi,Jayaprakash, Doss,Sasai, Hiroaki
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p. 3361 - 3371
(2008/09/19)
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- Chiral dinuclear vanadium(v) catalysts for oxidative coupling of 2-naphthols
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Preparation and structural analysis of chiral dinuclear vanadium(v) catalysts with high catalytic activity for the oxidative coupling of 2-naphthols are described. The Royal Society of Chemistry.
- Takizawa, Shinobu,Katayama, Tomomi,Kameyama, Chiaki,Onitsuka, Kiyotaka,Suzuki, Takeyuki,Yanagida, Takeshi,Kawai, Tomoji,Sasai, Hiroaki
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p. 1810 - 1812
(2008/12/22)
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- Asymmetric addition of phenylacetylene to aldehydes catalyzed by soluble optically active polybinaphthols ligand
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A chiral polymer ligand was synthesized by the polymerization of (S)-5,5′-dibromo-6,6′-dibutyl-2,2′-binaphthol (S-M-1) with (S)-2,2′-bishexyloxy-1,1′-binaphthyl-6,6′-boronic acid (S-M-2) via Pd-catalyzed Suzuki reaction. The application of the chiral poly
- Wu, Linglin,Zheng, Lifei,Zong, Lili,Xu, Jinqian,Cheng, Yixiang
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p. 2651 - 2657
(2008/09/19)
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- Synthesis and fluorescent properties of a chiral conjugated polymer based on (S)-2,2′-binaphtho-20-crown-6
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Linear conjugated polymer was obtained by the polymerization of 2,3-dibutoxy-1,4-diethynylnaphthalene (M-l) and (S)-5,5′-dibromo-6, 6′-dibutyl-2,2′-binaphtho-20-crown-6 (S-M-2) via Pd-catalyzed Sonogashira reaction. The conjugated polymer shows strong green-blue fluorescence due to the extended Π-electronic structure between the chiral repeating unit (S)-6,6′-dibutyl-2,2′-binaphtho-20-crown-6 and the conjugated linker 2,3-dibutoxynaphthyl group via acetylene bridge. The responsive properties of the chiral polymer on K+, Pb2+, Hg2+, and AsIII were investigated by fluorescent spectra. The results show that Hg2+ and AsIII can cause effective fluorescent quenching of the polymer, whereas, K+ and Pb2+ do not produce obvious changes in the polymer fluorescence. The obvious fluorescent influence shows that the 2,2′-binaphtho-20-crown-6 moiety plays an important role in fluorescent recognition for Hg2+ and AsIII due to the effective photoinduced electron transfer (PET) and charge transfer (PCT) between the conjugated polymer backbone and receptor species.
- Huang, Hui,Miao, Qian,Kang, Yixiong,Huang, Xiaobo,Xu, Jinqian,Cheng, Yixiang
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scheme or table
p. 1116 - 1124
(2009/05/06)
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- EPOXIDATION OF ALPHA, BETA-UNSATURATED KETONES
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The invention relates to the stereoselective epoxidation of α,β-unsaturated ketones bearing electron withdrawing substituents and to chiral 5-phenyl-4,5-dihydropyrazoles obtained therefrom.
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Page/Page column 32-33
(2010/11/25)
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- Highly enantioselective oxidative couplings of 2-naphthols catalyzed by chiral bimetallic oxovanadium complexes with either oxygen or air as oxidant
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The chiral bimetallic oxovanadium complexes have been designed for the enantioselective oxidative coupling of 2-naphthols bearing various substituents at C6 and/or C7. The chirality transferring from the amino acid to the axis of the biphenyl in oxovanadium complexes 2 was found to occur with the use of UV and CD spectra and DFT calculation. The homo-coupling reaction with oxygen as the oxidant was promoted by 5 mol % of an oxovanadium complex derived from L-isoleucine and achiral biphenol to afford binaphthols in nearly quantitative yields with high enantioselectivities of up to 98% ee. An oxovanadium complex derived from L-isoleucine and H8-binaphthol is highly efficient at catalyzing the air-oxidized coupling of 2-naphthols with excellent enantioselectivities of up to 97% ee. 51V NMR study shows that the oxovanadium complexes have two vanadium(V) species. Kinetic studies, the cross-coupling reaction, and HRMS spectral studies on the reaction have been carried out and illustrate that two vanadium(V) species are both involved in catalysis and that the coupling reaction undergoes a radical-radical mechanism in an intramolecular manner. Quantum mechanical calculations rationalize the importance of the cooperative effects of the axial chirality matching S-amino acids on the stereocontrol of the oxidative coupling reaction. The application of the transformation in the preparation of chiral ligands and conjugated polymers confirms the importance of the current process in organic synthesis.
- Guo, Qi-Xiang,Wu, Zhi-Jun,Luo, Zhi-Bin,Liu, Quan-Zhong,Ye, Jian-Liang,Luo, Shi-Wei,Cun, Lin-Feng,Gong, Liu-Zhu
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p. 13927 - 13938
(2008/09/19)
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- CHIRAL COMPOUNDS
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The invention relates to chiral compounds, methods of their preparation, and to their use in optical, electrooptical, electronic, semiconducting or luminescent components or devices, and in decorative, security, and cosmetic or diagnostic applications (F)
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Page/Page column 40-41; 47-48
(2008/06/13)
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- Highly twisted helical polyacetylene with morphology free from the bundle of fibrils synthesized in chiral nematic liquid crystal reaction field
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We synthesized novel axially chiral binaphthyl derivatives with highly twisting powers by substituting phenylcyclohexyl (PCH) mesogenic moieties into 2,2′ positions or 2,2′,6,6′ positions of binaphthyl rings. The di- and tetrasubstituted binaphthyl deriva
- Goh, Munju,Kyotani, Mutsumasa,Akagi, Kazuo
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p. 8519 - 8527
(2008/02/09)
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- Highly efficient chromatographic resolution of α,α′- dihydroxybiaryls
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(Graph Presented) Separation factors as high as 115 were observed for the chromatographic resolution of many α,α′-dihydroxybiaryls with a single chiral stationary phase made from readily available amino acid derivatives. The stationary phase works well for biphenyl-type compounds. It works extremely well for larger bis-aromatic compounds, such as binaphthyl-type compounds.
- Huang, Junmin,Li, Tingyu
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p. 5821 - 5823
(2007/10/03)
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- Tris(perfluoroalkyl)silyl entities as unexpectedly potent tags for the noncovalent immobilization of catalysts by fluorous-fluorous interactions: Application to the synthesis of several perfluoro-tagged ligands
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Unexpectedly high retention times were obtained in HPLC investigations for compounds equipped with (C8F17CH2CH 2)3Si tags on C8F17-modified silica gel (Fig. 4). Hence, these tags have a high potential for the noncovalent immobilization of catalysts to be applied in organic solvents, allowing for an easy separation and reuse of the catalyst by filtration and reapplication. The tris(perfluoroalkyl)silyl tag could be incorporated in a straightforward manner into ligands as demonstrated by the synthesis of several prominent classes of ligands (Schemes 4-6).
- Andrushko, Vasyl,Schwinn, Dominik,Tzschucke, Carl Christoph,Michalek, Florian,Horn, Joachim,Moessner, Christian,Bannwarth, Willi
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p. 936 - 949
(2007/10/03)
-
- Dual activation in a homolytic coupling reaction promoted by an enantioselective dinuclear vanadium(IV) catalyst
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A new concept of dual activation catalysis in homolytic coupling reaction of 2-naphthol derivatives is described. The dinuclear vanadium(IV) catalyst (R,S,S)-1a promotes the oxidative coupling reaction of 2-naphthol derivatives with high reactivity and enantioselectivity. This dual activation mechanism is supported by the fact that the reaction rate of oxidative coupling of 2-naphthol promoted by the (R,S,S)-1a is 48 times faster than that of the mononuclear complex (S)-3 and a lower catalyst loading of (R,S,S)-1a shows higher catalyst efficiency both in enantioselectivity and chemical yield.
- Somei, Hidenori,Asano, Yasuaki,Yoshida, Tomokazu,Takizawa, Shinobu,Yamataka, Hiroshi,Sasai, Hiroaki
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p. 1841 - 1844
(2007/10/03)
-
- Water soluble chiral diphoshpines
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The invention concerns a water soluble compound of formula (a) wherein: A represents naphthyl or phenyl; and Ar1 and Ar2 independently represent a saturated or aromatic carbocyclic group; Xa, Xb are independentl
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- Lipase-catalyzed stereoselective resolution and desymmetrization of binaphthols
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We have investigated the use of lipoprotein lipase enzymes from Pseudomonas sp. and Pseudomonas fluorescens for the enantioselective resolution and desymmetrization of racemic binaphthols. The reactions were carried out using a non-aqueous environment (iPr2O/acetone/vinyl acetate), and yielded mono-acetate ester products of the parent unsubstituted substrate, the 6,6′-dibromo-substrate, and the 6,6′-dimethoxy-substrate with high enantiomeric selectivity.
- Juarez-Hernandez, Marcela,Johnson, Dean V.,Holland, Herbert L.,McNulty, James,Capretta, Alfredo
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p. 289 - 291
(2007/10/03)
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- Convenient and highly efficient chromatographic resolution of BINOL and of 6,6′-dibromo-BINOL via N(α)-Boc-tryptophan esters
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Racemic [1,1′]binaphthalenyl-2,2′-diol (BINOL, (±)-1) has been esterified with various commercially available N-protected-L-amino acids, giving the corresponding diastereomeric esters. Their TLC separation factors were highly dependent on the amino acid pattern. Diesters of (±)-1 and N(α)-Boc-tryptophan (3a) showed unusually large separation factors, which allowed their efficient separation by simple column chromatography. Removal of the tryptophan moieties under very mild conditions furnished each enantiomer of 1 in high overall yield and 100% ee. This procedure was also successful for the resolution of racemic 6,6′-dibromo-[1,1′]binaphthalenyl-2,2′-diol (6,6′-dibromo-BINOL, (±)-2).
- Panchal, Bhavesh M.,Einhorn, Cathy,Einhorn, Jacques
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p. 9245 - 9248
(2007/10/03)
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- Catalytic asymmetric oxidative couplings of 2-naphthols by tridentate N-ketopinidene-based vanadyl dicarboxylates
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(Matrix presented) A series of oxovanadium(IV) complexes derived from tridentate N-ketopinidene-α-amino acids were synthesized. They serve as efficient catalysts for the enantioselective oxidative couplings of various 3-, 6-, or 7-substituted 2-naphthols. The best scenario involves the use of a vanadyl complex arising from L-tert-leucine in CCl4. The asymmetric couplings of 2-naphthols can be conducted smoothly at 40-45 °C under a stream of gaseous oxygen, leading to 2,2′dihydroxy-1,1′-binaphthyls in good yields (61-99%) and with enantioselectivities of up to 87%.
- Barhate, Nivrutti B.,Chen, Chien-Tien
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p. 2529 - 2532
(2007/10/03)
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