Binaphthyl Moiety Research Articles

ChemInform Abstract: A Chiral Rh‐Phosphite Complex Dislaying High Activity in the Enantioselective Rh‐Catalyzed Addition of Arylboronic Acids to Carbonyl Compounds: When and Why atropos Is Better Than tropos.

AbstractThe rhodium/deoxycholic acid complex bearing the atropoisomeric (S)‐binaphthyl moiety is shown to catalyze the asymmetric addition of arylboronic acids to aldehydes (I) or the challenging ketone (IV).

ChemInform Abstract: Palladium‐Catalyzed Asymmetric Hydrosilylation of 1,3‐Dienes

AbstractReview: 41 refs.

A binaphthol-substituted tetrathiafulvalene with axial chirality and its enantiopure TCNQF4 charge-transfer salts

A chiral tetrathiafulvalene (1) bearing a binaphtholdimethylene moiety on one side, an ethylenedithio substituent on the other side, is prepared from atropoisomeric (R)-, (S)- and racemic (R,S)-binaphthol. Its oxidation potential (0.49 V vs.SCE) allows for its oxidation with TCNQF4. Crystal structures of the neutral racemic (R,S)-1 and enantiopure (R)-1 were determined together with those of the enantiopure charge-transfer salts formulated as [(R)-1][TCNQF4]·CH2Cl2 and [(S)-1][TCNQF4]·CH2Cl2, the first enantiomeric salts of chiral TTFs with axial chirality. Despite the peculiar geometry adopted by the binaphthyl moieties in the constrained ten-membered ring in 1, stacking of the donor molecules is observed, both in the neutral state and in the TCNQF4 charge transfer salts where the (1)+˙ and (TCNQF4)−˙ radical species are associated, respectively, into [(1)2]2+ and [(TCNQF4)2]2− homodyads, both in their singlet state.

The Photooxidation of Bis(8‐dimethylaminonaphthyl) Ditelluride

AbstractThe photooxidation of (8‐Me2NC10H6Te)2 provided a complex reaction mixture from which the novel tetranuclear telluroxane cluster (8‐MeNC10H5TeO)4 (1) was isolated in 17 % yield. Compound 1 contains two 5,5′‐binaphthyl moieties that presumably formed by oxidation of C5–H bonds of the naphthyl ring. Upon formation of 1, one of the two methyl groups of the 8‐dimethylamino group was cleaved and the remaining coordinative Te···N bond turned into a covalent Te–N bond. In the solid‐state, individual molecules of 1 are associated through secondary Te···O interactions giving rise to a 1D coordination polymer.

ChemInform Abstract: Synthesis and Enantioselective Coloration of Optically Active Azophenolic Acerands Incorporating Two 1,1′-Binaphthyl Moieties as the Chiral Centre.

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ChemInform Abstract: Chiral 1‐Phenylethylamine‐Derived Phosphine—Phosphoramidite Ligands for Highly Enantioselective Rh‐Catalyzed Hydrogenation of β‐(Acylamino)acrylates: Significant Effect of Substituents on 3,3′‐Positions of Binaphthyl Moiety.

AbstractIntroduction of phenyl substituents at the phosphoramidite backbone of PEAPhos ligand (PEAPP) significantly increases its catalytic activity in the Rh‐catalyzed asymmetric hydrogenation of β‐(acylamino)acrylates.

Helical Nanostructures of an Optically Active Metal‐Free Porphyrin with Four Optically Active Binaphthyl Moieties: Effect of Metal–Ligand Coordination on the Morphology

AbstractAn optically active metal‐free porphyrin (1) with four chiral binaphthyl units attached at the meso‐phenyl substituents through crown ether moieties has been designed, synthesized, and characterized. Its self‐assembly behavior in the absence and presence of K+ was comparatively investigated by electronic absorption and circular dichroism (CD) spectra, transmission electron microscopy (TEM), scanning electron microscopy (SEM), atom force microscopy (AFM), and energy‐dispersive X‐ray (EDX) spectroscopy. In the absence of K+, metal‐free porphyrin self‐assembles into nanoparticles depending mainly on the van der Waals interaction among neighboring metal‐free molecules. In the presence of K+, additionally formed metal–ligand K–Ocrown coordination bonds between K+ and crown units of (R)‐ and (S)‐1 molecules, together with chiral discrimination of chiral side chains and intermolecular van der Waals interactions, induce a right‐handed and left‐handed helical arrangement in a stack of (R)‐ and (S)‐1 molecules, respectively, with an ordered “head‐to‐tail” internal molecular arrangement. This then further hierarchically self‐assembles into highly ordered fibrous nanostructures with a helicity opposite to that of the original porphyrin stack. This clearly reveals the effect of the metal–ligand coordination bonding interaction on the morphology and handedness of self‐assembled nanostructures.

Synthesis and Evaluation of Chiral Selectors with Multiple Hydrogen-Bonding Sites in the Macrocyclic Cavities

Chiral macrocycles with the hydrogen bond donor/acceptor sites in the cavity were synthesized and covalently bonded to silica gel to give chiral stationary phases (CSPs), which showed excellent abilities to resolve various chiral compounds including ketones, esters, carboxylic acids, sulfoxides, amines, amino acid derivatives, and metal complexes. The effect of the linker connecting the macrocyclic moiety to silica was examined, and a more electronegative substituent was found to be better. Various organic solvents could be used as the mobile phase to optimize the resolution efficiency of the CSPs. Although the separation factors (alpha) tended to decrease with an increase in the solvent polarity, remarkable solvent tolerance was also observed. In some cases, even MeCN and MeOH could be used for the complete resolution of enantiomers. The MM calculations suggested that the chiral recognition of Co(acac)(3) is achieved by a combination of steric interactions and hydrogen bonds between the carbonyl O atom coordinated to the Co atom and the macrocyclic amide NH groups. The attachment of substituents to the 3,3'-positions of the binaphthyl moiety improved chiral HPLC performance in some cases. In particular, CSP-1d, having the Br atoms, showed the best performance for several analytes.

Thiazolium-Tethering Rotaxane-Catalyzed Asymmetric Benzoin Condensation: Unique Asymmetric Field Constructed by the Cooperation of Rotaxane Components

Asymmetric benzoin condensation of aromatic aldehydes with two kinds of optically active rotaxanes possessing thiazolium salt moieties was studied. A binaphthyl group as the chiral auxiliary was introduced in either the wheel or the axle component of the rotaxanes. Rate of the catalytic benzoin condensation of benzaldehyde with a rotaxane catalyst without the binaphthyl moiety was compared with its axle component to understand the effect of wheel component. Among several solvents used, methanol was the best solvent, which showed the highest yield (98%) of benzoin in the presence of 5 mol% of either the rotaxane and the axle catalysts. The benzoin condensations of aromatic aldehydes catalyzed by the chiral rotaxanes were studied in detail and found to give optically active benzoins with 0–32% e.e. in 5–92% yield depending on the structure of the rotaxane and the reaction conditions employed. From the results, two intrarotaxane chirality transfers are confirmed: (i) through-space chirality transfer from wheel to axle and (ii) through-bond chirality transfer controlled with an achiral wheel. Because these asymmetric reaction fields are specific to the rotaxane structure, the importance and possibility of the “rotaxane field” as a particular reaction field are demonstrated.

Helical Nanostructures Self-Assembled from Optically Active Phthalocyanine Derivatives Bearing Four Optically Active Binaphthyl Moieties: Effect of Metal−Ligand Coordination on the Morphology, Dimension, and Helical Pitch of Self-Assembled Nanostructures

(R)- and (S)-enantiomers of optically active metal free tetrakis[11,12:13,14-di(1',2'-naphtho)-1,4,7,10,15,18-hexaoxacycloeicosa-2,11,13-trieno]-phthalocyanine and their zinc complexes, (R)- and (S)-H(2)Pc (1) and (R)- and (S)-ZnPc (2), were prepared from the tetramerization of corresponding phthalonitriles, (R)- and (S)-2,3-(4',5'-dicyanobenzo)-11,12:13,14-di(1',2'-naphtho)-1,4,7,10,15,18-hexaoxacycloeicosa-2,11,13-triene, in the absence and presence of Zn(OAc)(2).2H(2)O template, respectively, promoted by organic base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Their self-assembly behavior in the absence and presence of 4,4'-bipyridine has been comparatively investigated by electronic absorption and circular dichroism (CD) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) technique, and X-ray photoelectron spectroscopy (XPS). The metal free phthalocyanine self-assembles into highly ordered fibrous nanostructures (ca. 3 microm length, 70 nm width, and 125 nm helical pitch) with left-handed and right-handed helicity for (R)-1 and (S)-1, respectively, through the hierarchical manner via one-dimensional helices with chirality determined by the optically active binaphthyl side chains. In contrast, self-assembly of the phthalocyaninato zinc analogue leads to the formation of nanoparticles. However, in the presence of 4,4'-bipyridine, additionally formed metal-ligand Zn-N(4,4'-bipyridine) coordination bonds between the nitrogen atoms of additive 4,4'-bipyridine molecule and the zinc center of (R)- and (S)-2 molecules together with pi-pi interaction and chiral discrimination of chiral side chains induce a right-handed and left-handed helical arrangement in a stack of (R)- and (S)-2 molecules, respectively, which further hierarchically packs into highly ordered fibrous nanostructures of average tens of micrometers in length, 30 nm width, and 106 nm helical pitch with the same helicity to the stack, revealing the effect of metal-ligand coordination bonding interaction on the morphology, dimension, handedness, and helical pitch of self-assembled nanostructures.

Chiral 1-phenylethylamine-derived phosphine-phosphoramidite ligands for highly enantioselective Rh-catalyzed hydrogenation of β-(acylamino)acrylates: significant effect of substituents on 3,3′-positions of binaphthyl moiety

A series of new chiral phosphine-phosphoramidite ligands with a 3,3'-substituted binaphthyl moiety were prepared from 1-phenylethylamine, and successfully applied in the Rh-catalyzed asymmetric hydrogenation of beta-(acylamino)-acrylates. The research disclosed that the substituents on the 3,3'-positions of binaphthyl moiety significantly influenced the enantioselectivity.

Synthesis, characterization, and properties of a novel epoxy resin containing both binaphthyl and biphenyl moieties

AbstractA new epoxy resin containing both binaphthyl and biphenyl moieties in the skeleton (BLBPE) was synthesized and confirmed by electrospray ionization mass spectroscopy, 1H‐nuclear magnetic resonance spectroscopy, and infrared spectroscopy. To evaluate the combined influence of two moieties, one epoxy resin containing binaphthyl moiety and another containing biphenyl moiety were also synthesized, and a commercial biphenyl‐type epoxy resin (CER3000L) was introduced. Thermal properties of their cured polymers with phenol p‐xylene resins were characterized by differential scanning calorimetry, dynamic mechanical, and thermogravimetric analyses. The cured polymer obtained from BLBPE showed remarkably higher glass transition temperature and lower moisture absorption, as well as comprehensively excellent thermal stability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Application of Chiral Amine-Imine Ligands in Palladium-Catalyzed Polyketone Synthesis: Effect of Ligand Backbone on the Polymer Stereochemistry

Two pairs of enantiomerically pure chiral bidentate nitrogen-donor ligands (N*-N) featuring one sp3 and one sp2 nitrogen atom have been applied to the CO/vinyl arene copolymerization reaction catalyzed by the corresponding monocationic palladium(II) complexes [Pd(CH3)(CH3CN)(N*-N)][PF6]. The ligand fragment containing the sp2 nitrogen atom is a 2-pyridinyl or an 8-quinolinyl building block, while the chiral framework of the ligand derives from (S)-(+)-2,2′-(2-azapropane-1,3-diyl)-1,1′-binaphthalene or from trans-2,5-dimethylpyrrolidinyl. Ligands with the binaphthyl moiety generate catalysts showing a moderate activity, while ligands having the pyrrolidinyl fragment result in very low activity species. The stereochemistry of the synthesized polyketones depends on the sp2 nitrogen-containing fragment: ligands with the 2-pyridinyl group lead to atactic copolymers, whereas those with the quinolinyl moiety give an isotactic polyketone. The effect of the nature of the quinone, added to the reaction mixture as oxidant, has been investigated. MALDI-TOF analysis reveals the formation of several polymeric chains, differing in the presence of various end-groups.

Thermo and Photoresponsive Behavior of Liquid-Crystalline Helical Structures with the Aid of Dual Molecular Motions

Light- and temperature-driven multistable chiral materials composed of a binaphthyl moiety as a twisting part and an azobenzene moiety as a photoresponsive part in a single component were investigated. It has been found that the materials show reversible change in a dihedral angle of the twisting part at various temperatures. In contrast, no change in the twisting angle of the materials during trans−cis photoisomerization was observed. Furthermore, the chiral compounds were dissolved in nematic (N) liquid crystals (LCs) to produce a chiral N phase with a helical structure. The mixture exhibited a dual molecular response to temperature and light. Helical pitch length of the chiral N LC decreased with increasing temperature because of a molecular twisting motion of the binaphthyl moiety, resulting in a stabilization of the LC helical structure. On the other hand, length of the helical pitch increased upon photoirradiation, and the resulting LC mixture was found to show photoswitching between chiral N and N ...

Fluoride anion sensing using colorimetric reagents containing binaphthyl moiety and urea binding site

AbstractFour 1,1′-binaphthalene based bis-urea derivatives bearing aryl groups at end-on nitrogen atoms IIIa–d were synthesized as potential sensor molecules. These receptors show characteristic UV-VIS spectral changes on complexation with anions and they exhibit selective recognition of F− over other halide anions. Interaction of a fluoride anion with urea NH groups was confirmed by 1H NMR data. The presence of an electron-withdrawing nitro group in N′-aryls (receptors IIIa and IIIb) appeared to be necessary for naked-eye colorimetric detection. These receptors show dramatic color change from light-yellow to orange (IIIa) or to orange-red (IIIb) in the presence of guest fluoride anions already at concentrations of 10−5 mol dm−3 of the receptor and host.

Binaphthyl‐Containing Green‐ and Red‐Emitting Molecules for Solution‐Processable Organic Light‐Emitting Diodes

AbstractStrong intermolecular interactions usually result in decreases in solubility and fluorescence efficiency of organic molecules. Therefore, amorphous materials are highly pursued when designing solution‐processable, electroluminescent organic molecules. In this paper, a non‐planar binaphthyl moiety is presented as a way of reducing intermolecular interactions and four binaphthyl‐containing molecules (BNCMs): green‐emitting BBB and TBT as well as red‐emitting BTBTB and TBBBT, are designed and synthesized. The photophysical and electrochemical properties of the molecules are systematically investigated and it is found that TBT, TBBBT, and BTBTB solutions show high photoluminescence (PL) quantum efficiencies of 0.41, 0.54, and 0.48, respectively. Based on the good solubility and amorphous film‐forming ability of the synthesized BNCMs, double‐layer structured organic light‐emitting diodes (OLEDs) with BNCMs as emitting layer and poly(N‐vinylcarbazole) (PVK) or a blend of poly[N,N′‐bis(4‐butylphenyl)‐N,N′‐bis(phenyl)benzidine] and PVK as hole‐transporting layer are fabricated by a simple solution spin‐coating procedure. Amongst those, the BTBTB based OLED, for example, reaches a high maximum luminance of 8315 cd · m−2 and a maximum luminous efficiency of 1.95 cd · A−1 at a low turn‐on voltage of 2.2 V. This is one of the best performances of a spin‐coated OLED reported so far. In addition, by doping the green and red BNCMs into a blue‐emitting host material poly(9,9‐dioctylfluorene‐2,7‐diyl) high performance white light‐emitting diodes with pure white light emission and a maximum luminance of 4000 cd · m−2 are realized.

Tuning the Chiral Cavity of Macrocyclic Receptor for Chiral Recognition and Discrimination

The size and shape of the chiral cavity of a macrocyclic receptor were tuned by the alteration of the binaphthyl moiety to improve the chiral recognition/discrimination ability. For example, host 3 with the 3,5-bis(trifluoromethyl)phenyl group at the 3,3'-positions showed improved enantioselectivity for small molecules such as 2-chloropropionic acid and methyl lactate as evaluated by the binding constants. This host 3 also had an excellent ability as an NMR chiral solvating agent.

Synthesis of a series of soluble main-chain chiral nonracemic poly(alkyl-aryl ketone)

A series of main-chain chiral polyketones have been synthesized through condensation polymerization of a dihalide and a diketone with optically pure binaphthyl moiety as linkage in the polymer backbone. The solubility of the polymers can be easily enhanced by substituents at the alpha position next to the carbonyl groups. Reducing the steric hin- drance of the substituents in the monomers increases the reactivity of the polymerization. The chiral polymers exhibit large optical rotations. Circular Dichroism (CD) spectra of the polymers are similar to those of the corresponding monomers. The novel synthetic strategy may have great impact on future development of palladium catalyzed condensation polymeriza- tions. The highly soluble chiral polymers synthesized allow for preparation of materials in the form of thin films and have potentials applications in various areas such as chiral separation and recognition.

Study on the electronic effects on stereoconservativity of Suzuki coupling in chiral groove of binaphthyl

Suzuki diarylation of enantiopure 2,2′-diiodo-1,1′-binaphthyl catalyzed by triphenylphosphane palladium complex is accompanied by almost complete racemization of binaphthyl moiety (7% e.e.). Based on formerly proposed mechanism, secondary oxidative addition of Pd(II) to Pd(IV)-complex, competitive to transmetallation, is expected to be responsible for racemization. In accordance with it, racemization pathway can be suppressed in the favour of stereoconservative route by electronic factors, which control the rate of oxidative addition. Among the electronic factors, decreasing donating ability of the tested phosphane ligands resulted in increase of e.e. of the diarylated product up to 65%, using triindol-1-ylphosphane. However, this factor slows down also the rate of the primary oxidative addition that lowers the yield of the diarylated product. Further decrease in donating ability of the ligand makes palladium complex almost inactive in this cross-coupling reaction. Effect of the leaving group of binaphthyl 2,2′-dielectrophile (as a matter of the reactivity of C–X bond towards oxidative addition) was found to be even more dramatic: almost stereoconservative route in case of 2,2′-dibromo-1,1′-binaphthyl (95% e.e.), but no reaction in case of corresponding ditriflate.

Cu-catalyzed enantioselective conjugate addition of diethylzinc to cyclic enones with chiral phosphite ligands derived from 1,2:5,6-di- O-cyclohexylidene- d-mannitol

A new and readily in situ prepared catalytic system of copper salts with chiral P,N-ligands or aryl diphosphite ligand, which derived from 1,2:5,6-di- O-cyclohexylidene- d-mannitol, 1,1′-binaphthol, and phenyl isocyanate derivatives, were successfully employed in the enantioselective conjugate additions of diethylzinc to cyclic enones with up to 71% ee. Two notable cooperative effects of the stereochemistry of the ligands on the enantioselectivity were observed in the reactions: one between the phenylcarbamate substituent and the axially chiral binaphthyl moiety; another between the stereogenic centers of mannitol and the chiral binaphthol substituents. A significant dependence of the product yield and stereoselectivity on the ring size of the substrate using the ligand 1,2:5,6-di- O-cyclohexylidene-3,4-bis [( S)-1,1′-binaphthyl-2,2′-diyl]phosphite- d-mannitol was also observed: 71% ee for 2-cyclopentenone, 62% ee for 2-cyclohexenone, and 40% ee for 2-cycloheptenone.