Axially Dissymmetric Chiral (R)‐N,W‐Bis(2‐hydroxy‐3,5‐ditert‐butyl‐arylmethyl)‐1, 1′‐binaphthalene‐2,2′‐diamine as Chiral Ligands in the Reaction of Diethylzinc to Aldehydes†

Chiral ligand (A)‐N,N′‐Bis(2‐hydroxy‐3,5‐di‐tert‐butyl‐arylmethyl)‐1,1′‐binaphthalene‐2,2′‐diamine derived from the reduction of Schiff base (R)‐2,2′‐bis (3,5‐di‐tert‐butyl‐2‐hydroxybenzylideneamino)‐1, 1′‐binaphthyl with LiAlH₄, is fairly effective in the asymmetric addition reaction of diethylzinc to aldehydes by which good yields (46%‐94%) of the corresponding sec‐alcohols can be obtained in moderate ee (51%‐79%) with R configuration for a variety of aldehydes.     

A facile synthesis and asymmetric catalytic activity of new 3‐substituted chiral BINOL ligands

Three new chiral ligands, (S)‐3‐(1H‐imidazol‐1‐yl)methyl‐1,1′‐binaphthol [(S)‐ 1 ], (S)‐3‐(1H‐1,2,3‐benzotriazol‐1‐yl)methyl‐1,1′‐binaphthol [(S)‐ 2 ] and (S)‐3‐(2H‐1,2,3‐benzotriazol‐2‐yl)methyl‐1,1′‐binaphthol [(S)‐ 3 ], were prepared by a simple method. They showed moderate catalytic properties for the asymmetric addition of diethylzinc to benzaldehyde in the presence of titanium tetraisopropoxide. Copyright © 2007 John Wiley & Sons, Ltd.     

A Facile Synthesis of Enantiomerically Pure (R)‐6‐Arylbinols

This work reported a convenient method for the preparation of enantiomerically pure 6‐aryl‐2,2′‐dihydroxy‐1,1′‐binaphthyl derivatives starting from the commercially available (R)‐2,2′‐hydroxy‐1,1′‐binaphthyl [(R)‐ 1 ] via bromination, hydrolysis and Suzuki cross coupling reaction. This novel synthetic method was characterized with high regioselectivity, simple operation, mild reaction conditions, and excellent yield (up to 73%). On the other hand, we synthesized the target unknown compounds, which were confirmed by IR, ¹H NMR, ¹³C NMR, MS and elementary analysis.     

Chloro(η6‐p‐cymene)(phosphoramidite)ruthenium(II), a 16‐Electron Fragment Stabilized by an η2‐Aryl–Metal Interaction,and Its Use in Asymmetric Cyclopropanation

Chloride abstraction from the half‐sandwich complexes [RuCl₂(η⁶‐p‐cymene)(P*‐κP)] ( 2a : P* = (S_a,R,R)‐ 1a = (1S_a)‐[1,1′‐binaphthalene]‐2,2′‐diyl bis[(1R)‐1‐phenylethyl)]phosphoramidite; 2b : P* = (S_a,R,R)‐ 1b = (1S_a)‐[1,1′‐binaphthalene]‐2,2′‐diyl bis[(1R)‐(1‐(1‐naphthalen‐1‐yl)ethyl]phosphoramidite) with (Et₃O)[PF₆] or Tl[PF₆] gives the cationic, 18‐electron complexes dichloro(η⁶‐p‐cymene){(1S_a)‐[1,1′‐binaphthalene]‐2,2′‐diyl {(1R)‐1‐[(1,2‐η)‐phenyl]ethyl}[(1R)‐1‐phenylethyl]phosphoramidite‐κP}ruthenium(II) hexafluorophosphate ( 3a ) and [Ru(S)]‐dichloro(η⁶‐p‐cymene){(1S_a)‐[1,1′‐binaphthalene]‐2,2′‐diyl {(1R)‐1‐[(1,2‐η)‐naphthalen‐1‐yl]ethyl}[(1R)‐1‐(naphthalen‐1‐yl)ethyl]phosphoramidite‐κP)ruthenium(II) hexafluorophosphate ( 3b ), which feature the η²‐coordination of one aryl substituent of the phosphoramidite ligand, as indicated by ¹H‐, ¹³C‐, and ³¹P‐NMR spectroscopy and confirmed by an X‐ray study of 3b . Additionally, the dissociation of p‐cymene from 2a and 3a gives dichloro{(1S_a)‐[1,1′‐binaphthalene]‐2,2′‐diyl [(1R)‐(1‐(η⁶‐phenyl)ethyl][(1R)‐1‐phenylethyl]phosphoramidite‐κP)ruthenium(II) ( 4a ) and di‐μ‐chlorobis{(1S_a)‐[1,1′‐binaphthalene]‐2,2′‐diyl [(1R)‐1‐(η⁶‐phenyl)ethyl][(1R)‐1‐phenylethyl]phosphoramidite‐κP}diruthenium(II) bis(hexafluorophosphate) ( 5a ), respectively, in which one phenyl group of the N‐substituents is η⁶‐coordinated to the Ru‐center. Complexes 3a and 3b catalyze the asymmetric cyclopropanation of α‐methylstyrene with ethyl diazoacetate with up to 86 and 87% ee for the cis‐ and the trans‐isomers, respectively.     

Synthesis and chirooptical properties of optically active poly(ester imide)s based on axially asymmetric 1,1′‐binaphthyls

A series of optically active poly(ester imide)s (PEsI's) has been synthesized by the polycondensation reactions of new axially asymmetric dianhydrides, that is, (R)‐2,2′‐bis(3,4‐dicarboxybenzoyloxy)‐1,1′‐binaphthyl dianhydride and (S)‐2,2′‐bis(3,4‐dicarboxybenzoyloxy)‐1,1′‐binaphthyl dianhydride, and various diamines with aromatic, semiaromatic, and aliphatic structures. The polymers have inherent viscosities of 0.45–0.70 dL/g, very good solubility in common organic solvents, glass‐transition temperatures of 124–290 °C, and good thermal stability. Wide‐angle X‐ray crystallography of these polymers shows no crystal diffraction. In comparison with model compounds, an enhanced optical rotatory power has been observed for the repeat unit of optically active PEsI's based on aromatic diamines, and it has been attributed to a collaborative asymmetric perturbation of chiral 1,1′‐binaphthyls along the rigid backbones. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4318–4326, 2004     

Helical Poly(α,β‐unsaturated ketone) with Bulky Pendant of Binaphthyl from Anionic Polymerization of ((−)‐Menthyl (S)‐6′‐Acrylyl‐2′‐methyloxy‐1,1′‐binaphthalene‐2‐carboxylate

((?)‐Menthyl (S)‐6′‐acrylyl‐2′‐methyloxy‐1,1′‐binaphthalene‐2‐carboxylate ( 3 ) was synthesized and anionically polymerized using n‐BuLi as an initiator in toluene. The monomer 3 was levorotatory and had an [α]_D²⁵ value of ?72.4, but its corresponding polymer poly‐ 3 was dextrorotatory and showed an [α]_D²⁵ value of +162.0. Poly‐ 3 was confirmed to exist in the form of one‐handed helical structure in solution by means of comparing the specific optical rotation and the CD spectra with that of 3 and the model compounds such as (?)‐menthyl (S)‐6′‐propionyl‐2′‐methyloxy‐1,1′‐binaphthalene‐2‐carboxylate 2b and (?)‐menthyl (S)‐6′‐heptanoyl‐2′‐methyloxy‐1,1′‐binaphthalene‐2‐carboxylate 2c . This conclusion was also confirmed by the fact that the g‐value of poly‐ 3 is about 11 times of that of monomer 3 .     

8,14,30,36‐Tetramethoxy[2.0.2.0](1,6)naphthalenophane‐1,19‐diyne: A Double‐Helically Twisted Cyclophane by Diastereoselective Dimerization

The title compound and its corresponding etheno‐ and ethano‐bridged compounds were successfully synthesized in enantiomerically pure form by McMurry coupling of 2,2′‐dimethoxy‐(R)‐ or ‐(S)‐1,1′‐binaphthyl‐6,6′‐dicarbaldehydes as the key reaction. The reaction proceeded in a highly diastereoselective manner; the reaction of the racemic dialdehyde did not afford the meso coupling product but gave only the racemic one in poor yield. The diyne crystallized in the chiral monoclinic space group P2₁ from toluene/hexane. Structural analysis reveals that it has a considerably twisted double‐helical structure in crystal form. The spectral properties (NMR, UV/Vis, and CD) clearly indicate the highly strained nature of the molecule. In particular, its UV/Vis and CD spectra exhibit a bathochromic shift of about 20 nm for the naphthyl π–π* transitions.     

Organophosphate‐accelerated copper‐catalyzed C(sp2)–C(sp) Sonogashira‐type cross couplings

A dramatic acceleration in copper‐catalyzed Sonogashira‐type reactions was observed when an organophosphate was used as additive. The catalyst systems featuring low copper loading (0.5 mol% < Cu < 5 mol%) gave Sonogashira‐type products with a broad scope of aromatic and aliphatic terminal alkynes as well as aryl iodides in good to excellent yields. Among the organophosphate/copper catalytic systems, that of 4 mol% Cu(OTf)₂/10 mol% (R)‐(?)‐1,1′‐binaphthyl‐2,2′‐diyl hydrogenphosphate exhibited the highest catalytic activity. Copyright © 2015 John Wiley & Sons, Ltd.     

Rheological behavior and microstructure of 2,2′‐dioxy‐ 1,1′‐binaphthylphosphazene R/S random copolymer

Solutions of a binaphthoxy phosphazene copolymer (containing chiral 2,2′‐dioxy‐1,1′‐binaphthyl units with 50% R and S configurations distributed along the chains) in N‐methyl pyrrolidone were studied by means of continuous flow experiments and small amplitude oscillatory flow tests. A sudden viscosity decrease was observed in the polymer concentration range (39–40 wt %), evidencing a liquid‐crystalline polymer behavior. This has been confirmed by other rheological methods which have demonstrated that, for a sufficiently high concentration, the solutions of the binaphthoxy phosphazene copolymer give rise to a lyotropic system with formation of rigid rods (axial ratio of 10) stacked parallel to each other. The lyotropic properties of our binaphthoxy phosphazene copolymer are compatible with a regular helical structure, similar to that found for a homoleptic binaphthoxy phosphazene, which contains only S configuration. This suggests that the chains of 50% R/S binaphthoxy phosphazene copolymer are, in average, close to the strictly alternating R‐S copolymeric structure of the syndiotactic isomer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010     

Asymmetric Hydroformylation of Vinylfurans Catalyzed by {(11bS)‐4‐{[(1R)‐2′‐Phosphino[1,1′‐binaphthalen]‐2‐yl]oxy}dinaphtho[2,1‐d:1′,2′‐f]‐ [1,3,2]dioxaphosphepin}rhodium(I) [RhI{(R,S)‐binaphos}] Derivatives

The asymmetric hydroformylation of 2‐ and 3‐vinylfurans ( 2a and 2b , resp.) was investigated by using [Rh{(R,S)‐binaphos}] complexes as catalysts ((R,S)‐binaphos = (11bS)‐4‐{[1R)‐2′‐phosphino[1,1′‐binaphthalen]‐2‐yl]oxy}dinaphtho[2,1‐d:1′,2′‐f][1,3,2]dioxaphosphepin; 1 ). Hydroformylation of 2 gave isoaldehydes 3 in high regio‐ and enantioselectivities (Scheme 2 and Table). Reduction of the aldehydes 3 with NaBH₄ successfully afforded the corresponding alcohols 5 without loss of enantiomeric purity (Scheme 3).     

(2E)‐N‐(2‐Iodo‐4,6‐dimethylphenyl)‐2‐methylbut‐2‐enamide

The title compound, C₁₄H₁₈INO, crystallizes as +sc/+sp/+sc 2‐iodoanilide molecules (and racemic opposites) and shows significant intermolecular I...O interactions in the solid state, forming dimeric pairs about centres of symmetry. Under asymmetric Heck conditions, the S enantiomer of the dihydroindol‐2‐one was obtained using (R)‐(+)‐2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl [(R)‐BINAP], suggesting a mechanism that proceeds by oxidative addition to give the title (P) enantiomer of the compound and pro‐S coordination of the Re face of the alkene in a conformation similar to that defined crystallographically, except that rotation about the C—C bond of the butenyl group is required.     

Novel ortho‐linked fluorinated poly(ether‐imide)s based on 2,2′‐substituted 1,1′‐binaphthyl units

In this research, a new fluorinated diamine based on 2,2′‐substituted 1,1′‐binaphthyl units, 2,2′‐bis(2‐amino‐4‐trifluoromethylphenoxy)‐1,1′‐binaphthyl (AFPBN) was synthesized and then used to prepare the corresponding ortho‐linked poly(ether‐imide)s via chemical polyimidization with several aromatic carboxylic dianhydrides. The resulting poly(ether‐imide)s were fully characterized by FT‐IR, NMR, viscosity measurements, gel‐permeation chromatography, UV–vis, X‐ray diffraction, organo‐solubility, thermogravimetric analysis (TGA), and differential scanning calorimetry. Probing optical behavior of the colorless films prepared from these poly(ether‐imide)s demonstrated that they possess a high degree of optical transparency, and UV–visible absorption cut‐off wavelength values were found to be in the range of 404–471 nm. The resulting polymers exhibited excellent organo‐solubility in polar solvents such as dimethylformamide, dimethyl sulfoxide, pyridine, and even tetrahydrofuran. To investigate the heat stability of the samples, their thermograms obtained from TGA were plotted, and for example, it is found that the 10% weight loss temperature of representative polymer AFPBN/3,3′,4,4′‐benzophenonetetracarboxylic dianhydride occurred at 532°C in nitrogen. These poly(ether‐imide)s had glass‐transition temperatures (T_g's) up to 280°C. Two previously prepared analogues of AFPBN, i.e. nonfluorinated diamine DAM1 and para‐linked fluorinated diamine DAM2 used to prepare the corresponding poly(ether‐imide)s, were also considered to compare the results obtained. Copyright © 2012 John Wiley & Sons, Ltd.     

Synthesis and chiroptical properties of chiral binaphthyl‐containing polyfluorene derivatives

New chiral binaphthyl‐containing polyfluorene (PF) derivatives, PFOH , PFMOM , and PFP , bearing different binaphthyl units ((S)‐2,2′‐bis(methoxymethoxy)‐1,1′‐binaphthyl for PFMOM , (S)‐1,1′‐binaphthyl‐2,2′‐diol for PFOH , and (S)‐2,2′‐bis(diphenylphosphinyl)‐1,1′‐binaphthyl for PFP ) in the backbone have been designed and synthesized through Pd‐catalyzed Suzuki polycondensation. Their properties have been investigated in detail by ¹H NMR, ¹³C NMR, TGA, DSC, UV–vis, photoluminescence (in solutions, in thin films before and after annealing), and circular dichroism (CD) spectroscopic methods compared with poly(9,9‐dihexylfluorene‐2,7‐diyl) ( PF ). The resulting copolymers possessed excellent solubility in organic solvents and emitted strong blue light. The phosphine oxide‐containing copolymers PFP and PFMOM exhibited higher quantum yields and better thermal spectral stability in comparison with PF . All the copolymers exhibited obviously the linearly polarized photoluminescent properties both in solutions and in solid states. High emission polarization ratios (R_PL) of PFP were observed with no obvious decrease upon thermal annealing. In addition, investigation of the CD spectroscopic properties of these copolymers in THF solutions indicated that the chirality of the binaphthyls could be transferred to the whole PF backbone. All these results demonstrated that introduction of the chiral binaphthyls, particularly BINAPO, into the backbone could effectively improve the performances of the copolymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis of dendronized,chiral conjugated polymers with appendant Fréchet‐type dendrons

New chiral binaphthyl‐based polyarylenes [(S)‐ 3a and (S)‐ 3b ] with appendant Fréchet‐type poly(aryl ether) dendrons (first generation and second generation) were synthesized with Suzuki polycondensation from chiral (S)‐6,6′‐dibromo‐2,2′‐didendron‐substituted 1,1′‐binaphthyl derivatives and p‐phenylene diboronic acid. The polymers were studied with circular dichroism, fluorescence, and ultraviolet–visible spectra. Laser light scattering measurements of (S)‐ 3a and (S)‐ 3b showed that their weight‐average molecular weights were 2.39 × 10⁵ and 1.09 × 10⁴, respectively. The specific optical rotation [α]_D was ?59.6 for (S)‐ 3a and ?62.7 for (S)‐ 3b . These dendronized conjugated polymers exhibited good thermal stability. The glass‐transition temperatures and the initial decomposition temperatures were 187.5 and 265.3 °C for (S)‐ 3a and 173.8 and 308.9 °C for (S)‐ 3b , respectively. (S)‐ 3a and (S)‐ 3b had high fluorescence quantum efficiencies, 87 and 91%, respectively, in tetrahydrofuran. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1167–1172, 2002     

Donor‐Induced Helical Inversion of 1,1′‐Binaphthyl Connecting with Two Molybdenum Complexes

An atropisomeric biaryl molecule with a given absolute configuration could present two opposite helical conformations through the rotation around C? C single bond. To the best of our knowledge, the biaryl system is the simplest helical inversion model apart from stereomutation between two enantiomers. Herein, we first report such true helical inversion phenomena of biaryl compounds. Two [Mo^VIO₂(L)]‐type complexes, in which L is a tridentate dioxoanionic pyridine O,N,O‐ligand, are coalesced on the 2,2′,3,3′‐positions of an (R)‐1,1′‐binaphthyl unit and an intramolecular dioxo bridge is formed by two Mo?O???Mo interactions. Exterior strong donors can coordinate to molybdenum to interrupt this dioxo bridge and inversions from negative to positive chirality are explicitly observed by circular dichroism spectroscopy, consistent with single‐crystal X‐ray diffraction analyses.     

Flip‐type disorder in 3‐substituted 2,2′:5′,2′′‐terthiophenes

In the crystal structures of four thiophene derivatives, (E)‐3′‐[2‐(anthracen‐9‐yl)ethenyl]‐2,2′:5′,2′′‐terthiophene, C₂₈H₁₈S₃, (E)‐3′‐[2‐(1‐pyrenyl)ethenyl]‐2,2′:5′,2′′‐terthiophene, C₃₀H₁₈S₃, (E)‐3′‐[2‐(3,4‐dimethoxyphenyl)ethenyl]‐2,2′:5′,2′′‐terthiophene, C₂₂H₁₈O₂S₃, and (E,E)‐1,4‐bis[2‐(2,2′:5′,2′′‐terthiophen‐3′‐yl)ethenyl]‐2,5‐dimethoxybenzene, C₃₆H₂₆O₂S₆, at least one of the terminal thiophene rings is disordered and the disorder is of the flip type. The terthiophene fragments are far from being coplanar, contrary to terthiophene itself. The central C—C=C—C fragments are almost planar but the bond lengths suggest slight delocalization within this fragment. The crystal packing is determined by van der Waals interactions and some weak, relatively short, C—H...S and C—H...π directional contacts.     

Modular amino acids and β‐amino alcohol‐based chiral ligands for enantioselective addition of diethylzinc to aromatic aldehydes

Enantioselective addition of diethylzinc to a series of aromatic aldehydes was developed using a modular amino acids and ${\bf \beta}$ ‐amino alcohol‐based chiral ligand (2R)‐N‐[(1R,2S)‐1‐hydroxy‐1‐phenylpropan‐2‐yl]‐3‐phenyl‐2‐(tosylamino) propanamide ( 1f ) without using titanium complex. The catalytic system employing 15 mol% of 1f was found to promote the addition of diethylzinc (ZnEt₂) to a wide range of aromatic aldehydes with electron‐donating and electron‐withdrawing substituents, giving up to 97% ee of the corresponding secondary alcohol under mild conditions. Copyright © 2010 John Wiley & Sons, Ltd.     

NMR characterization of 1,1′‐binaphthyl‐2,2′‐diyl hydrogen phosphate binding to chiral molecular micelles

NMR spectroscopy was used to characterize the binding of the chiral compound 1,1′‐binaphthyl‐2,2′‐diyl hydrogen phosphate (BNP) to five molecular micelles with chiral dipeptide headgroups. Molecular micelles have covalent linkages between the surfactant monomers and are used as chiral mobile phase modifiers in electrokinetic chromatography. Nuclear overhauser enhancement spectroscopy (NOESY) analyses of (S)‐BNP:molecular micelle mixtures showed that in each solution the (S)‐BNP interacted predominately with the N‐terminal amino acid of the molecular micelle's dipeptide headgroup. NOESY spectra were also used to generate group binding maps for (S)‐BNP:molecular micelle mixtures. In these maps, percentages are assigned to the (S)‐BNP protons to represent the relative strengths of their interactions with a specified molecular micelle proton. All maps showed that (S)‐BNP inserted into a previously reported chiral groove formed between the molecular micelle's dipeptide headgroup and hydrocarbon chain. In the resulting intermolecular complexes, the (S)‐BNP protons nearest to the analyte phosphate group were found to point toward the N‐terminal Hα proton of the molecular micelle headgroup. Finally, pulsed field gradient NMR diffusion experiments were used to measure association constants for (R) and (S)‐BNP binding to each molecular micelle. These K values were then used to calculate the differences in the enantiomers' free energies of binding, Δ(ΔG). The NMR‐derived Δ(ΔG) values were found to scale linearly with electrokinetic chromatography (EKC) chiral selectivities from the literature. Copyright © 2010 John Wiley & Sons, Ltd.     

Asymmetric Hydroformylation of 4‐Vinyl‐1,3‐dioxolan‐2‐one

A chiral cyclic carbonate, 4‐vinyl‐1,3‐dioxolan‐2‐one was used as racemic substrate in asymmetric hydroformylation. The catalysts were formed in situ from “pre‐formed” PtCl₂(diphosphine) and tin(II) chloride. (2S,4S )‐2,4‐Bis(diphenylphosphinopentane ((S,S )‐BDPP)), (S,S )‐2,3‐O‐izopropylidine‐2,3‐dihydroxy‐1,4‐bis(diphenylphosphino)butane ((S,S )‐DIOP)), and (R )‐2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl ((R )‐BINAP)) were used as optically active diphosphine ligands. The platinum‐containing catalytic systems provided surprisingly high activity. The hydroformylation selectivities of up to 97% were accompanied by perfect regioselectivity towards the dioxolane‐based linear aldehyde. The enantiomeric composition of all components in the reaction mixture was determined and followed throughout the reaction. The unreacted 4‐vinyl‐1,3‐dioxolan‐2‐one was recovered in optically active form. The kinetic resolution was rationalized using the enantiomeric composition of the substrate and the products.     

Substituted 2,2′‐Bis(2‐oxidobenzylideneamino)‐4,4′‐dimethyl‐1,1′‐biphenyl Complexes of Zinc

The condensation reaction of 2,2′‐diamino‐4,4′‐dimethyl‐6,6'‐dibromo‐1,1′‐biphenyl with 2‐hydroxybenzaldehyde as well as 5‐methoxy‐, 4‐methoxy‐, and 3‐methoxy‐2‐hydroxybenzaldehyde yields 2,2′‐bis(salicylideneamino)‐4,4′‐dimethyl‐6,6′‐dibromo‐1,1′‐biphenyl ( 1a ) as well as the 5‐, 4‐, and 3‐methoxy‐substituted derivatives 1b , 1c , and 1d , respectively. Deprotonation of substituted 2,2′‐bis(salicylideneamino)‐4,4′‐dimethyl‐1,1′‐biphenyls with diethylzinc yields the corresponding substituted zinc 2,2′‐bis(2‐oxidobenzylideneamino)‐4,4′‐dimethyl‐1,1′‐biphenyls ( 2 ) or zinc 2,2′‐bis(2‐oxidobenzylideneamino)‐4,4′‐dimethyl‐6,6′‐dibromo‐1,1′‐biphenyls ( 3 ). Recrystallization from a mixture of CH₂Cl₂ and methanol can lead to the formation of methanol adducts. The methanol ligands can either bind as Lewis base to the central zinc atom or as Lewis acid via a weak O–H ··· O hydrogen bridge to a phenoxide moiety. Methanol‐free complexes precipitate as dimers with central Zn₂O₂ rings.