cas 20439-47-8, (1R,2R)-(-)-1,2-Diaminocyclohexane

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Chiral redox-Active isosceles triangles
Designing small-molecule organic redox-active materials, with potential applications in energy storage, has received considerable interest of late. Herein, we report on the synthesis, characterization, and application of two rigid chiral triangles, each of which consist of non-identical pyromellitic diimide (PMDI) and naphthalene diimide (NDI)-based redox-active units. 1H and 13C NMR spectroscopic investigations in solution confirm the lower symmetry (C2 point group) associated with these two isosceles triangles. Single-crystal X-ray diffraction analyses reveal their rigid triangular prism-like geometries. Unlike previously investigated equilateral triangle containing three identical NDI subunits, both isosceles triangles do not choose to form one-dimensional supramolecular nanotubes by dint of [C-H···O] interaction-driven columnar stacking. The rigid isosceles triangle, composed of one NDI and two PMDI subunits, forms in the presence of N,N-dimethylformamidetwo different types of intermolecular NDI-NDI and NDI-PMDI stacked dimers with opposite helicities in the solid state. Cyclic voltammetry reveals that both isosceles triangles can accept reversibly up to six electrons. Continuous-wave electron paramagnetic resonance and electron-nuclear double-resonance spectroscopic investigations, supported by density functional theory calculations, on the single-electron reduced radical anions of the isosceles triangles confirm the selective sharing of unpaired electrons among adjacent redox-active NDI subunit(s) within both molecules. The isosceles triangles have been employed as electrode-active materials in organic rechargeable lithium-ion batteries. The evaluation of the structure-performance relationships of this series of diimide-based triangles reveals that the increase in the number of NDI subunits, replacing PMDI ones, within the molecules improves the electrochemical cell performance of the batteries.
Nalluri, Siva Krishna Mohan,Liu, Zhichang,Wu, Yilei,Hermann, Keith R.,Samanta, Avik,Kim, Dong Jun,Krzyaniak, Matthew D.,Wasielewski, Michael R.,Stoddart, J. Fraser
p. 5968 - 5977
(2016)
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Using enantioselective dispersive liquid–liquid microextraction for the microseparation of trans-cyclohexane-1,2-diamine enantiomers
A new chiral separation system effective for the enantioselective extraction of racemic trans-cyclohexane-1,2-diamine is presented. Enantioselective dispersive liquid–liquid microextraction has been used for the chiral microseparation of trans-cyclohexane-1,2-diamine, with a chiral azophenolic crown ether being identified as a versatile chiral selector. The influence of various process conditions on the extraction performance was studied experimentally. It was found that the operational selectivity in one extraction step is mainly related to the type and volume of the solvents, chiral selector concentration, extraction time, temperature of sample solution, and pH. At optimum conditions (300?μL of diethyl ether as the extraction solvent 1?mL of methanol as the disperser solvent, with 5?mmol?L?1 chiral selector concentration, pH of the sample equal to 4.5, 30?min extraction time and a temperature of 10?°C), the distribution ratio of (R,R)- and (S,S)-trans-cyclohexane-1,2-diamine was 18.3 and 1.8, respectively, while the enantioselectivity value of 10.2 was found at the optimum condition.
Hashemi, Majid,Hadjmohammadi, Mohammad Reza
p. 454 - 459
(2017)
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Pd-Catalyzed asymmetric allylation involving bis(diamidophosphite) based on the salen-type chiral diamine
New bis(diamidophosphite) ligand with stereogenic phosphorus atoms in the 1,3,2-diaza-phospholidine rings was synthesized based on (1R,2R)-[N, N′-bis(3-hydroxybenzylidene)]-1,2-diaminocyclohexane. This ligand provided up to 73% ee in Pd-catalyzed asymmetric allylic alkylation of (E)-1,3-diphenylallyl acetate with dimethyl malonate and up to 80% ee in its amination with pyrrolidine, with the starting substrate conversion being quantitative.
Gavrilov,Chuchelkin,Gavrilov,Zheglov,Firsin,Trunina,Maximychev,Perepukhov
p. 336 - 339
(2021)
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Synthesis, characterization, and nucleophilic ring opening reactions of cyclohexyl-substituted β-haloamines and aziridinium ions
Cyclohexyl-substituted β-haloamines and aziridinium ions were prepared and characterized. Stereospecific ring opening of aziridinium ions was applied for efficient synthesis of vicinal amine, β-amino acid, and tetrahydroisoquinoline (THIQ) analogues. Nucleophilic ring opening reactions of aziridinium ions and N-protected aziridine analogues were for the first time comparatively studied. The result of nucleophilic reactions clearly indicates that aziridinium ions were significantly more reactive toward nucleophilic ring opening than the aziridine analogues.
Chong, Hyun-Soon,Sun, Xiang,Chen, Yunwei,Wang, Meng
p. 946 - 948
(2015)
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Spectroscopic exploration of binding of new imidazolium-based palladium(II) saldach complexes with CT-DNA as anticancer agents against HER2/neu overexpression
The HER2/neu has shown a potential role in the choice of active chemotherapy for breast tumors because of its prognostic relevance and putative role in predicting drug resistance. Moreover, suppressing DNA replication has become an attractive strategy for treating cancer patients. In this attempt, the present study aimed to prepare new series of bis-imidazolium-based saldach {H2(Et)2saldach (nBu-Im+-X–)2} and their cis-Pd(II) complexes (saldach = N,N′-bis-(salicylidene)-R,R-1,2-diaminocyclohexane; X = Cl, PF6, BF4) as anticancer agents. The in vitro cytotoxicity activity of new cis-Pd(II) complexes against human breast adenocarcinoma cell lines (MCF-7) revealed higher growth-inhibitory effect than the native ligands. They induced a significant decrease for the protein HER2/neu expression with p 50 = 8.5 ± 0.2 μM) in inhibition of cell proliferation. Additionally, in vitro studies of Pd(II) complex (5a) using UV–Vis spectroscopy and binding affinity toward the calf thymus (CT) DNA) showed a combination of covalent, intercalation, hydrogen bonding interactions through formation of (CT-DNA).
Alfaifi, Mohammad Y.,Elbehairi, Serag Eldin I.,Hafez, Hani S.,Elshaarawy, Reda F.M.
p. 118 - 128
(2019)
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Thermochemical and Structural Studies of New Chiral and Achiral Long Alkyl Chain Functionalized Imidazolinium Ionic Liquids
Adding to the versatile class of ionic liquids (ILs), an entirely new series of imidazolinium-based ionic liquids is reported herein, offering chirality and important thermal characteristics, such as polymorphism, glass transition, and plastic crystalline behavior. An efficient and general procedure for the preparation of long N,N′-alkyl chain-substituted compounds with either saturated (s) or chiral (c) cyclohexyl (cyC6)-substituted imidazolium (Im) backbones, namely, [C12C12RsIm][A] (A = Br-, [BF4]-, [ClO4]-, [PF6]- R = H, Me, iPr) and [C12C12cIm-cyC6][A] (A = Br-, I-, [I3]-, [BF4]-, [ClO4]-, [PF6]-, [SbF6]-, [BPh4]-), was developed, and the novel compounds were studied by thermochemical methods (DSC, TGA), X-ray diffraction in the small angle regime (SAXS), single-crystal X-ray diffraction (SC-XRD), and specific rotation analysis.
Seidl, Vera,Sternberg, Michelle,Heinemann, Frank W.,Schmiele, Martin,Unruh, Tobias,Wasserscheid, Peter,Meyer, Karsten
p. 6276 - 6288
(2021/10/20)

Design and synthesis of cage-like NADH model molecule intermediate with multi-chiral centers
Studying NADH molecules is one of the most active areas in biomimetic research. It is important to design novel and efficient chiral NADH model molecules. Herein, a cage-like NADH model with multi-chiral centers was designed, and key intermediates have been synthesized. In this study, we found that pentafluorophenoxy group is an excellent leaving group for our synthetic route.
Zhang, Tong,Bai, Cui-Bing,Wu, Yue-Hua,Wang, Nai-Xing,Xu, Bao-Cai,Yan, Zhan,Xing, Yalan
supporting information
p. 410 - 416
(2019/02/05)

Synthesis of Chiral Triazole-Based Halogen Bond Donors
The number of applications that use halogen bonding in the fields of self-assembly, supramolecular aggregation, and catalysis is growing. However, the accessibility of chiral halotriazoles shows that there is still a lot more to explore. The simple click-chemistry is applied for the straightforward synthesis of enantiomerically pure mono- and bidentate as well as multifunctional iodotriazole-based XB donors. The methodology is characterized by a wide variability due to easy access of chiral azides.
Kaasik, Mikk,Kaabel, Sandra,Kriis, Kadri,J?rving, Ivar,Kanger, T?nis
supporting information
p. 2128 - 2135
(2019/05/10)

Discrete Dimers of Redox-Active and Fluorescent Perylene Diimide-Based Rigid Isosceles Triangles in the Solid State
The development of rigid covalent chiroptical organic materials, with multiple, readily available redox states, which exhibit high photoluminescence, is of particular importance in relation to both organic electronics and photonics. The chemically stable, thermally robust, and redox-active perylene diimide (PDI) fluorophores have received ever-increasing attention owing to their excellent fluorescence quantum yields in solution. Planar PDI derivatives, however, generally suffer from aggregation-caused emission quenching in the solid state. Herein, we report on the design and synthesis of two chiral isosceles triangles, wherein one PDI fluorophore and two pyromellitic diimide (PMDI) or naphthalene diimide (NDI) units are arranged in a rigid cyclic triangular geometry. The optical, electronic, and magnetic properties of the rigid isosceles triangles are fully characterized by a combination of optical spectroscopies, X-ray diffraction (XRD), cyclic voltammetry, and computational modeling techniques. Single-crystal XRD analysis shows that both isosceles triangles form discrete, nearly cofacial PDI-PDI π-dimers in the solid state. While the triangles exhibit fluorescence quantum yields of almost unity in solution, the dimers in the solid state exhibit very weak - yet at least an order of magnitude higher - excimer fluorescence yield in comparison with the almost completely quenched fluorescence of a reference PDI. The triangle containing both NDI and PDI subunits shows superior intramolecular energy transfer from the lowest excited singlet state of the NDI to that of the PDI subunit. Cyclic voltammetry suggests that both isosceles triangles exhibit multiple, easily accessible, and reversible redox states. Applications beckon in arenas related to molecular optoelectronic devices.
Mohan Nalluri, Siva Krishna,Zhou, Jiawang,Cheng, Tao,Liu, Zhichang,Nguyen, Minh T.,Chen, Tianyang,Patel, Hasmukh A.,Krzyaniak, Matthew D.,Goddard, William A.,Wasielewski, Michael R.,Stoddart, J. Fraser
supporting information
p. 1290 - 1303
(2019/01/21)

Controlled Exchange of Achiral Linkers with Chiral Linkers in Zr-Based UiO-68 Metal-Organic Framework
The development of highly robust heterogeneous catalysts for broad asymmetric reactions has always been a subject of interest, but it remains a synthetic challenge. Here we demonstrated that highly stable metal-organic frameworks (MOFs) with potentially acid-labile chiral catalysts can be synthesized via postsynthetic exchange. Through a one- or two-step ligand exchange, a series of asymmetric metallosalen catalysts with the same or different metal centers are incorporated into a Zr-based UiO-68 MOF to form single- and mixed-M(salen) linker crystals, which cannot be accomplished by direct solvothermal synthesis. The resulting MOFs have been characterized by a variety of techniques including single-crystal X-ray diffraction, N2 sorption, CD, and SEM/TEM-EDS mapping. The single-M(salen) linker MOFs are active and efficient catalysts for asymmetric cyanosilylation of aldehydes, ring-opening of epoxides, oxidative kinetic resolution of secondary alcohols, and aminolysis of stilbene oxide, and the mixed-M(salen) linker variants are active for sequential asymmetric alkene epoxidation/epoxide ring-opening reactions. The chiral MOF catalysts are highly enantioselective and completely heterogeneous and recyclable, making them attractive catalysts for eco-friendly synthesis of fine chemicals. This work not only advances UiO-type MOFs as a new platform for heterogeneous asymmetric catalysis in a variety of syntheses but also provides an attractive strategy for designing robust and versatile heterogeneous catalysts.
Tan, Chunxia,Han, Xing,Li, Zijian,Liu, Yan,Cui, Yong
supporting information
p. 16229 - 16236
(2018/11/27)

Asymmetric Grignard Synthesis of Tertiary Alcohols through Rational Ligand Design
A simple, general and practical method is reported for highly enantioselective construction of tertiary alcohols through the direct addition of organomagnesium reagents to ketones. Discovered by rational ligand design based on a mechanistic hypothesis, it has an unprecedented broad scope. It utilizes a new type of chiral tridentate diamine/phenol ligand that is easily removed from the reaction mixture. It is exemplified by application to a formal asymmetric synthesis (>95:5 d.r.) of vitamin E.
Bieszczad, Bartosz,Gilheany, Declan G.
supporting information
p. 4272 - 4276
(2017/04/03)

A novel water-soluble highly selective “switch-on” ionic liquid-based fluorescent chemi-sensor for Ca(II)
A novel chemi-sensor involve new bis-ionic Schiff base sensor (BISBS), N,N′-bis-[5-((2,4-lutidiniumchloride)methylene)-3-methoxysalicylidene]-R,R-1,2-cyclohexanediimine, has been synthesized and characterized. BISBS chemi-sensor was designed based on internal charge transfer (ICT) fluorescence mechanism. This new water soluble chemi-sensor provides great selectivity fluorescence detection for Ca(II) ions in an important physiological pH range. Moreover, the interaction of Ca(II) with the deprotonated BISBS to produce a metal-ligand complex with a ratio of (1: 1) accompanying with an enhancement in the intensity of emission band located at 502?nm. Fluorescence switching-on during the chemical interaction between BISBS and Ca(II) ions is very easily noticed with naked eye, but other metal cations such as alkali, alkaline earth and transition metal don't give any fluorescence changes. The novel developed BISBS sensor successively offers low limit of detection (LOD) 1.5?nM and fast tracing of Ca(II) in the physiological pH?7.6. Thus BISBS may provide a novel auspicious methodology for detection calcium cations in the environmental and biological samples.
Elshaarawy, Reda F.M.,Ali, Reham,Saleh, Sayed M.,Janiak, Christoph
p. 308 - 315
(2017/06/19)

Method for synthesizing trans-cyclohexyldiamine
The invention discloses a method for synthesizing trans-cyclohexyldiamine. The method comprises the following steps: by using epoxy cyclohexane as the raw material, carrying out ring opening with ammonia water, adding sulfuric acid for dewatering and salification, adding free alkali, carrying out ring opening with ammonia water, and distilling to obtain the trans-cyclohexyldiamine. The method has the advantages of high repetitiveness of the synthesis route, and simple and accessible raw materials, and provides an alternative scheme for obtaining the trans-cyclohexyldiamine pure product.
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(2017/08/29)

Method for separating chiral amine compound and intermediate thereof
The present invention discloses a method for separating a chiral amine compound and an intermediate thereof. The method comprises the following steps: salt forming reaction of the chiral amine compounds and a resolving agent in a solvent; the chiral amine compound is 3-(1-aminoethyl) phenol, (2R, 3S) 4-amino-1, 2, 3-cyclopentyl triol or trans-cyclohexanediamine; the resolving agent is L-alpha-amino acid, an L-alpha-amino acid derivative, D-alpha amino acid or a D-alpha amino acid derivative; the method can be used for better separation of the chiral amine compound, the method has high yield and low cost, and is suitable for industrialized production.
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Paragraph 0053-0056

(2017/07/22)

Preparation method of 1,2-cyclohexylenediamine
The invention provides a preparation method of 1,2-cyclohexylenediamine. The method adopts a one-step technology to prepare 1,2-cyclohexylenediamine. The method is simple, and simple, easily available and cheap 2-aminocyclohexanol is adopted as a raw material, so the production cost is effectively reduced, and large-scale industrial production is facilitated.
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Paragraph 0024; 0025

(2017/01/02)

METHOD OF PRODUCING OPTICALLY ACTIVE TRANS-1,2-DIAMINOCYCLOHEXANE
A method produces optically active trans-1,2-diaminocyclohexane, in which a crystal of optically active trans-1,2-diaminocyclohexane is obtained by crystallization from a solution of optically active trans-1,2-diaminocyclohexane. Optically active trans-1,2-diaminocyclohexane with high purity is obtained in a favorable yield from a solution of optically active trans-1,2-diaminocyclohexane. The optically active trans-1,2-diaminocyclohexane with high purity is useful as a raw material for a large number of medicines.
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Paragraph 0054

(2016/02/28)

Efficient chiral resolution of (±)-cyclohexane-1,2-diamine
A novel and efficient method has been developed for the chiral resolution and separation from cis-cyclohexane-1,2-diamine of (±)-cyclohexane-1,2- diamine, which reacts with xylaric acid, a substitute for tartaric acid. This method provides (1R,2R)-cyclohexane-1,2-diamine, and (1S,2S)-cyclohexane-1,2- diamine and cis-cyclohexane-1,2-diamine in good yield with high optical purity.
Gao, Chuan-Zhu,Wang, Tian-Shuai,Chen, Jia,Fei, Fan,Zhang, Yan,Yang, Bo
p. 490 - 492
(2014/11/08)

Enantioselective formal aza-Diels-Alder reactions of enones with cyclic imines catalyzed by primary aminothioureas
A highly enantio- and diastereoselective synthesis of indolo- and benzoquinolizidine compounds has been developed through the formal aza-Diels-Alder reaction of enones with cyclic imines. This transformation is catalyzed by a new bifunctional primary aminothiourea that achieves simultaneous activation of both the enone and imine reaction components.
Lalonde, Mathieu P.,McGowan, Meredeth A.,Rajapaksa, Naomi S.,Jacobsen, Eric N.
supporting information
p. 1891 - 1894
(2013/04/10)

Selective and nonselective aza-michael additions catalyzed by a chiral zirconium bis-diketiminate complex
Reaction of the chiral bis-diketiminate complex rac- or (R,R)-C 6H10(nacnacXyl)2ZrCl2 with AgOTf yielded the corresponding bis-triflate complex. The complex geometry changes from distorted octahedral in the dichloride complex to a pseudotetrahedral coordination involving π coordination of the diketiminate ligands. The bis-triflate complex is highly active for aza-Michael additions with turnover frequencies of 20000/h for the addition of morpholine to acrylonitrile and 1000/h for the addition of morpholine to methacrylonitrile. The enantioselectivities of the latter reaction in various solvents were low, never surpassing 19% ee. The reaction is first-order in olefin concentration and second order in amine concentration, which is explained by its participation as a base in the reaction mechanism. The presence of catalytic amounts of triethylamine slightly increases the observed rate constants and reduces the reaction order in amine to first order. Other activated alkenes such as methacrylonitrile, crotonitrile, methyl acrylate, and cyclohexenone can be employed, but no reactivity is observed toward styrene or vinyl ethers. Primary amines, secondary amines, and anilines can be employed as nucleophiles with activities correlating with their nucleophilicity, but the catalyst is unstable in the presence of alcohols.
El-Zoghbi, Ibrahim,Kebdani, Myriam,Whitehorne, Todd J. J.,Schaper, Frank
p. 6986 - 6995
(2014/01/06)

Synthesis of new diaza-18-crown-6 ethers derived from trans-(R,R)-1,2- diaminocyclohexane and investigation of their enantiomeric discrimination ability with amino acid ester salts
The synthesis of four diaza-18-crown-6 ethers with C2-symmetry derived from trans-(R,R)-1,2-diaminocyclohexane bearing methyl, phenyl and phenoxymethyl moeities attached to a stereogenic centre on the crown ring were achieved. Enantiomeric discrimination of these macrocycles against amino acid methyl ester salts was examined by 1H NMR titration method. They exhibit strong binding ability and some of them show a very high enantioselectivity towards amino acid esters, corresponding to 5.37 kJ/mol of binding energy difference in CDCl3 at 25 °C. Computational modelling showed parallel results with experimental calculations, thus providing a detailed understanding of molecular recognition mode and binding sites between the hosts and the guests.
Karakaplan, Mehmet,Ak, Devran,?olak, Mehmet,Kocakaya, ?afak ?zhan,Ho?g?ren, Halil,Pirin??io?lu, Necmettin
p. 349 - 358
(2013/01/15)

Dual catalyst system for asymmetric alternating copolymerization of carbon dioxide and cyclohexene oxide with chiral aluminum complexes: Lewis base as catalyst activator and lewis acid as monomer activator
Optically active aluminum complexes such as Schiff base, binuclear β-ketoiminate, and bisprolinol complexes were found to promote asymmetric alternating copolymerizations of carbon dioxide and cyclohexene oxide. The aluminum Schiff base complexes-tetraethylammonium acetate afforded isotactic poly(cyclohexene carbonate)s with low enantioselectivities. Lewis bases having two coordinating sites were utilized to enhance activity and selectivity based on the binuclear structure of the aluminum β-ketoiminate clarified by X-ray crystallography. [2gAlMe]2-bulky bisimidazole produced the alternating copolymer with high enantioselectivity (62% ee). The polymerization is considered to preferentially proceed at more crowded, enantioselective site owing to coordination of bulky Lewis bases to aluminums in less enantioselective sites. 32AlMe-2-picoline also exhibited a high enantioselectivity (67% ee). Methylaluminum bis(2,6-di-tert-butyl-4-methylphenoxide) was applied to perform faster and more enantioselective copolymerizations at low temperature (82% ee). The asymmetric copolymerizations were found to be significantly dependent on size of epoxide, temperature, and kind/amount of activators.
Nishioka, Kiyoshi,Goto, Hidetoshi,Sugimoto, Hiroshi
p. 8172 - 8192
(2013/01/15)

Stable chiral salen Mn(III) complexes with built-in phase-transfer capability for the asymmetric epoxidation of unfunctionalized olefins using NaOCl as an oxidant
A series of novel chiral salen Mn(III) complexes with inherent phase-transfer capability were prepared by covalent linkage of the limidazolium IL moieties containing various PEG chains with chiral salen ligand at two sides of 5,5′-position. Technologies of characterization well suggested the presence of polyether chain, the IL linker, and the intact active sites in the complexes. The amphipathic nature of the PEG chain allowed the PEG-based catalysts to undergo built-in phase transfer, which in turn increased the reaction rates in water/organic biphasic systems. Enantioselective epoxidation of styrene, α-methylstyrene, indene, 1,2-dihydronaphthalene, 6-cyano-2,2-dimethylchromene, and 6-nitro-2,2-dimethylchromene catalyzed by the complexes with NaOCl gave >99% conversions within 60 min. The enantiomeric excess (ee) for the epoxides was in the range of 68-93%, except for styrene (ee, 35%) and α-methylstyrene (ee, 42%). Furthermore, the PEG-based complexes were stable and could be separated from the reaction mixture by control of the solvent.
Luo, Rongchang,Tan, Rong,Peng, Zhigang,Zheng, Weiguo,Kong, Yu,Yin, Donghong
experimental part
p. 170 - 177
(2012/03/27)

Mechanism of living lactide polymerization by dinuclear indium catalysts and its impact on isoselectivity
A family of racemic and enantiopure indium complexes 1-11 bearing bulky chiral diaminoaryloxy ligands, H(NNOR), were synthesized and fully characterized. Investigation of both the mono- and the bis-alkoxy-bridged complexes [(NNOR)InX]2[μ-Y][μ-OEt] (5, R = tBu, X = Y = Cl; 8, R = Me, X = I, Y = OEt) by variable temperature, 2D NOESY, and PGSE NMR spectroscopy confirmed dinuclear structures in solution analogous to those obtained by single-crystal X-ray crystallography. The dinuclear complexes in the family were highly active catalysts for the ring-opening polymerization (ROP) of lactide (LA) to form poly(lactic acid) (PLA) at room temperature. In particular, complex 5 showed living polymerization behavior over a large molecular weight range. A detailed investigation of catalyst stereoselectivity showed that, although (R,R/R,R)-5 is highly selective for l-LA, only atactic PLA is obtained in the polymerization of racemic LA. No such selectivity was observed for complex 8. Importantly, the selectivities obtained for the ROP of racemic LA with (R,R/R,R)-5 and (R,R/R,R)-8 are different and, along with kinetics investigations, suggest a dinuclear propagating species for these complexes.
Yu, Insun,Acosta-Ramirez, Alberto,Mehrkhodavandi, Parisa
supporting information; experimental part
p. 12758 - 12773
(2012/09/05)

Synthesis and characterization of cobalt(iii) cyanide complexes: Cobalt participation in the decomposition of radical anion of TCNQ
Reaction of Co(CH3COO)2·4H2O, KTCNQ (TCNQ = 7,7,8,8-tetracyanoquinodimethane) with the racemic or chiral H 2salency (N,N′-bis(salicylidene)-1,2-cyclohexanediamine) ligand afforded three Co(iii) complexes K[Co(salency)(CN)2]·CH 3OH (1), K[Co(S,S-salency)(CN)2]·H2O (1S) and K[Co(R,R-salency)(CN)2]·CH3OH (1R), which have been fully characterized. The cyanide groups in these three complexes are generated from the in situ decomposition of the radical anion of TCNQ with the participation of cobalt(ii). Single-crystal X-ray diffraction analysis reveals that complex 1 exhibits an infinite double stair-like chain structure. However, the chiral complexes 1S and 1R show chain structures consisting of two independent sub-chains. All of these chains are bridged by the K+ ions, with the cyanides interacting with K+ in the end-on and unusual side-on π-type mode. Second-order nonlinear optical effect studies in the solid state revealed that 1S and 1R are SHG active. The Royal Society of Chemistry.
Tan, Chun-Hong,Ma, Xiao,Zhu, Qi-Long,Huang, Yi-Hui,Wen, Yue-Hong,Hu, Sheng-Min,Sheng, Tian-Lu,Wu, Xin-Tao
p. 8708 - 8713
(2013/02/23)

When is an imine not an imine? Unusual reactivity of a series of Cu(ii) imine-pyridine complexes and their exploitation for the Henry reaction
In this paper we report the synthesis and solid-state structures for a series of pyridine based Cu(ii) complexes and preliminary data for the asymmetric Henry reaction. Interestingly, the solid-state structures indicate the incorporation of an alcohol into one of the imine groups of the ligand, forming a rare α-amino ether group. The complexes have been studied via single crystal X-ray diffraction, EPR spectroscopy and mass spectrometry. Intriguingly, it has been observed that the alcohol only adds to one of the imine moieties. Density functional theory (DFT) calculations have also been employed to rationalise the observed structures. The Cu(ii) complexes have been tested in the asymmetric Henry reaction (benzaldehyde + nitromethane or nitroethane) with ee's up to 84% being achieved as well as high conversions and modest diastereoselectivities. The Royal Society of Chemistry 2011.
Cooper, Christine J.,Jones, Matthew D.,Brayshaw, Simon K.,Sonnex, Benjamin,Russell, Mark L.,Mahon, Mary F.,Allan, David R.
supporting information; experimental part
p. 3677 - 3682
(2011/07/30)

Ready available chiral azapyridinomacrocycles n-oxides; First results as lewis base catalysts in asymmetric allylation of p-nitrobenzaldehyde
We report here the straightforward synthesis of the first series of enantiomerically pure azapyridinomacrocycles N-oxides containing a cyclohexyl chiral moiety. These compounds were readily obtained in good overall yields by a convergent synthesis using natural amino acids as starting building blocks and macrocyclisation as the key step. This method is rapid, efficient and suitable for the introduction of various substituents at the macrocyclic skeleton. Finally, the compounds were tested as organocatalysts for the enantioselective allylation of p-nitrobenzaldehyde with allyltrichlorosilane.
Veitia, Maite Sylla-Iyarreta,Joudat, Mounia,Wagner, Mathieu,Falguieres, Annie,Guy, Alain,Ferroud, Clotilde
p. 2011 - 2039
(2011/10/19)

Chiral relay in NHC-mediated asymmetric β-lactam synthesis I; substituent effects in NHCs derived from (1R,2R)-cyclohexane-1,2-diamine
The synthesis of a range of C2-symmetric imidazolinium salts from (1R,2R)-cyclohexane-1,2-diamine, and an evaluation of the reactivity and asymmetric induction of the derived NHCs as catalysts for the asymmetric synthesis of β-lactams, is reported. In this series, optimal enantioselectivity (up to 70% ee) is observed using N-benzyl or N-1-naphthylmethyl-substituted NHCs, consistent with a chiral relay effect operating to dictate the stereochemical outcome of this reaction.
Duguet, Nicolas,Donaldson, Adele,Leckie, Stuart M.,Douglas, James,Shapland, Peter,Brown, Thomas B.,Churchill, Gwydion,Slawin, Alexandra M.Z.,Smith, Andrew D.
experimental part
p. 582 - 600
(2010/08/19)

Squaramide-catalyzed enantioselective michael addition of diphenyl phosphite to nitroalkenes
chemical equation presented Michael's a square: An easily prepared squaramide catalyst that promotes the highly enantioselective Michael addition reaction of diphenyl phosphite to a range of nitroalkenes is described. This method leads to chiral β-nitro phosphonates, which are precursors to biologically active β-amino phosphonic acids.
Zhu, Ye,Malerich, Jeremiah P.,Rawal, Viresh H.
supporting information; experimental part
p. 153 - 156
(2010/03/30)

Enantioselective reduction of α-substituted ketones mediated by the boronate ester TarB-NO2
A facile and mild reduction procedure is reported for the preparation of chiral secondary alcohols prepared from α-substituted ketones using sodium borohydride and the chiral boronate ester (l)-TarB-NO2. Direct reduction of substituted ketones bearing Lewis basic heteroatoms generally provided secondary alcohols of only modest enantiomeric excess likely due to either competition between the target carbonyl and the functionalized sidechains at the Lewis acidic boron atom in TarB-NO2 or the added steric bulk of the α-sidechain. As an alternative method, these substrates were synthesized using TarB-NO2 via a two-step procedure involving the reduction of an α-halo ketone to a chiral terminal epoxide, followed by regioselective/regiospecific epoxide opening by various nucleophiles. This procedure provides access to a variety of functionalized secondary alcohols including β-hydroxy ethers, thioethers, nitriles, and amines with enantiomeric excesses of 94% and yields up to 98%.
Eagon, Scott,Ball-Jones, Nicholas,Haddenham, Dustin,Saavedra, Jaime,Delieto, Cassandra,Buckman, Matthew,Singaram, Bakthan
experimental part
p. 6418 - 6421
(2010/12/30)

Synthesis of monoacylated derivatives of 1,2- cyclohexanediamine. Evaluation of their catalytic activity in the preparation of Wieland-Miescher ketone
Ureas, carbamoyl derivatives, amides, and sulfonamides can be easily prepared from the strained (R,R)-cylohexanediamine urea (1) in high yield, leaving a free amino group that shows good catalytic activity in intramolecular aldol condensations. The preparation of Wieland-Miescher ketone has been studied with these catalysts.
Fuentes De Arriba, Angel L.,Seisdedos, David G.,Simon, Luis,Alcazar, Victoria,Raposo, Cesar,Moran, Joaquin R.
experimental part
p. 8303 - 8306
(2011/02/27)

Easily recyclable polymeric ionic liquid-functionalized chiral salen Mn(III) complex for enantioselective epoxidation of styrene
A polymeric ionic liquid (IL)-functionalized chiral salen ligand (PICL) was synthesized by covalent polymerization between amino ({single bond}NH2) group of 1,3-dipropylamineimidazolium bromide with chloromethyl ({single bond}CH2Cl) group at two sides of 5,5′ positions in the typical chiral salen ligand. Treatment of the synthesized PICL with Mn(OAc)2s4H2O and LiCl under aerobic oxidation yielded the corresponding polymeric IL-functionalized chiral salen Mn(III) complex (PICC). The typical IR bands at 1613, 1540, 570, and 412 cm-1, as well as the maximum UV-vis absorbed peaks around 433 nm of the PICC were proposed as characteristics of the monomeric salen Mn(III) complex. The PICC was used as a catalyst in the enantioselective epoxidation of styrene. Comparable catalytic activity and enantioselectivity relative to the monomeric chiral salen Mn(III) complex were observed. Furthermore, recovery of the polymeric catalyst was readily accomplished by simple precipitation in n-hexane, and subsequently reused (10 times) without significant loss of reactivity and enantioselectivity.
Tan, Rong,Yin, Donghong,Yu, Ningya,Zhao, Haihong,Yin, Dulin
experimental part
p. 284 - 291
(2009/07/10)

METHOD FOR FRACTIONATING STEREOISOMERIC COMPOUNDS
The present invention relates to a method for fractionating stereoisomeric compounds which have at least one alcohol and/or amino group.
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Page/Page column 14

(2009/02/11)

Instantaneous low temperature gelation by a multicomponent organogelator liquid system based on ammonium salts
A new synergistic multicomponent organogelator liquid system (MOGLS) was discovered during the standard protocol of tartaric acid-mediated racemic resolution of (±)-trans-1,2-diaminocyclohexane. The MOGLS is formed by a 0.126 M methanolic solution of (1R,2R)-(+)-1,2-diaminocyclohexane L-tartrate and 1 equiv of concentrated hydrochloric acid. Nonreversible gelation of oxygenated and nitrogenated solvents occurs efficiently at low temperature. Several features make this system unique: (1) it is a multicomponent solution where each of the five components is required for the organogelation property; (2) the multicomponent organogelator liquid system (MOGLS) is formed by simple, small, and commercially available chiral building blocks dissolved in a well-defined solvent system (MeOH/HCl/H2O); (3) the chiral building blocks are easily amenable for further modifications in structure-property relationship studies; (4) the gelation phenomenon takes place efficiently at low temperature upon warming up the isotropic solution, conversely to the typical gel preparation protocol (gel formation upon cooling down the isotropic solution); (5) the formed organic gels are not thermoreversible in spite of the noncovalent interactions that hold the 3D-fibrillar network together.
Velázquez, Daniel García,Díaz, David Díaz,Ravelo, ángel Gutiérrez,Tellado, José Juan Marrero
supporting information; experimental part
p. 7967 - 7973
(2009/02/02)

Synthesis of 7-Epi (+)-FR900482: An epimer of comparable anti-cancer activity
(Chemical Equation Presented) FR900482 is a potent anti-tumor therapeutic that has been investigated as a replacement candidate for the clinically useful Mitomycin C. Herein, we report synthesis and biological testing of 7-Epi (+)-FR900482, which demonstrates equal potency relative to the natural product against several cancer cell lines. Highlights of this work include utilization of our palladium-catalyzed DYKAT methodology and development of a Polonovski oxidative ring expansion strategy to yield this equipotent epimer in 23 linear steps.
Trost, Barry M.,O'Boyle, Brendan M.
supporting information; experimental part
p. 1369 - 1372
(2009/04/10)

A new sparteine surrogate for asymmetric deprotonation of N-Boc pyrrolidine
(Chemical Equation Presented) The s-BuLi complex of a cyclohexane-derived diamine is as efficient as s-BuLi/(-)-sparteine for the asymmetric deprotonation of N-Boc pyrrolidine. This is the first example of high enantioselectivity using a non-sparteine-like diamine in such reactions. The ( S, S)-diamine is a useful (+)-sparteine surrogate and was utilized in short syntheses of (-)-indolizidine 167B and an intermediate for the synthesis of the CCK antagonist (+)-RP 66803.
Stead, Darren,O'Brien, Peter,Sanderson, Adam
supporting information; experimental part
p. 1409 - 1412
(2009/04/12)

A new approach to enantiomerically pure bis-imidazoles derived from trans-1,2-diaminocyclohexane
Racemic as well as enantiomerically pure trans-1,1′-(cyclohexane-1,2-diyl)bis(imidazole N-oxides) were prepared from trans-cyclohexane-1,2-bis(methylidenamine) and 1,2-dione monooximes (α-hydroxyiminoketones). The enantiomeric purity of selected products was determined by means of 1H NMR spectroscopy in the presence of (+)-(R)-(tert-butyl)(phenyl)phosphonothioic acid as a chiral solvating agent. Deoxygenation by treatment with Raney-nickel led to the corresponding chiral bis-imidazoles.
Mucha, Paulina,Mloston, Grzegorz,Jasinski, Marcin,Linden, Anthony,Heimgartner, Heinz
p. 1600 - 1607
(2008/12/21)

PREPARATION OF PLATINUM(II) COMPLEXES
This invention relates to a method for the preparation of a platinum(II) complex containing a neutral bidentate ligand, such as oxaliplatin. The method includes the step of reacting a halogenoplatinum complex containing a neutral bidentate ligand with an oxalate salt in a solvent, wherein more than 1 g/L of the oxalate salt is soluble in the solvent. The invention also relates to new platinum(II) complexes.
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(2008/06/13)

Enantioselective analysis of an asymmetric reaction using a chiral fluorosensor
(Chemical Equation Presented) An axially chiral 1,8-dipyridylnaphthalene N,N′-dioxide has been employed in enantioselective fluorescence analysis of the enzymatic kinetic resolution of trans-1,2-diaminocyclohexane. The procedure eliminates cumbersome purification and derivatization steps required by traditional methods. The results demonstrate the potential of fluorescence spectroscopy using suitable chiral chemosensors for real-time analysis of the enantiomeric composition of chiral compounds and for high-throughput screening of asymmetric reactions.
Tumambac, Gilbert E.,Wolf, Christian
p. 4045 - 4048
(2007/10/03)

Resolution of β-aminoalcohols and 1,2-diamines using fractional crystallization of diastereomeric salts of dehydroabietic acid
(S)-(+)-1-Amino-3-phenyloxy-2-propanol, (R)-(-)-2-amino-1-phenylethanol, (S)-(+)-1-amino-2-propanol, (1S,2S)-(+)-2-aminocyclohexanol and (1S,2S)-(+)-1,2-diaminocyclohexane were resolved using dehydroabietic acid. It was shown that good to high enantiomeric purity, between 81～>99% ee, was obtained and that dehydroabietic acid could be easily and efficiently recovered in a reusable form.
Guangyou, Zhang,Yuquing, Liao,Zhaohui, Wang,Nohira, Hiroyuki,Hirose, Takuji
p. 3297 - 3300
(2007/10/03)

Improved resolution methods for (R,R)- and (S,S)-cyclohexane-1,2-diamine and (R)- and (S)-BINOL
Starting from inexpensive L-(+)-tartaric acid, it was possible to resolve and obtain pure both enantiomers of trans-cyclohexane-1,2-diamine 1 and thence both enantiomers of BINOL 2, two of the most powerful, chiral inducing backbones in asymmetric catalysis. The modified method is very economic, not only due to an almost doubling of the overall yields of enantiomerically pure compounds (86% 1, 83% 2) but also due to the easy recovery of resolving agent 1 [66% (R,R)-1, 79% (S,S)-1] in the BINOL resolution. An improvement in the yield of the preparation of racemic BINOL is also recorded.
Schanz, Hans-Joerg,Linseis, Michael A.,Gilheany, Declan G.
p. 2763 - 2769
(2007/10/03)

Enantioselective epoxidation of non-functionalised alkenes using a urea-hydrogen peroxide oxidant and a dimeric homochiral Mn(III)-Schiff base complex catalyst
The catalytic enantioselective epoxidation of chromenes, indene and styrene using a urea-hydrogen peroxide adduct as an oxidising agent and the novel dimeric homochiral Mn(III)-Schiff base catalyst 1 has been investigated in the presence of carboxylate salts and nitrogen and oxygen coordinating co-catalysts. Conversions of more than 99% were obtained with all alkenes except styrene. Absolute chiral induction, as determined by 1H NMR using the chiral shift reagent (+)-Eu(hfc)3, was obtained in the case of nitro- and cyanochromene. The catalyst could be re-used for up to five cycles with some loss of activity due to degradation of the catalyst under epoxidation condition with retention of e.e.'s.
Kureshy, Rukhsana I,Khan, Noor-ul H.,Abdi, Sayed H.R,Patel, Sunil.T.,Jasra, Raksh V.
p. 433 - 437
(2007/10/03)

The stereospecific addition of hydroxylamines to α,β-unsaturated sulfones, nitriles and nitro compounds
N-Alkyl hydroxylamines have been shown to undergo a highly stereospecific cis addition to α,β-unsaturated sulfones, nitriles and nitro compounds.
O'Neil, Ian A.,Cleator, Ed,Southern, J. Mike,Bickley, Jamie F.,Tapolczay, David J.
p. 8251 - 8254
(2007/10/03)

An efficient method for opening nonactivated aziridines with TMS azide: Application in the synthesis of chiral 1,2-diaminocyclohexane
A variety of N-substituted aziridines have been opened with TMS azide in MeCN at rt in the absence of any Lewis acid. The reaction was extended to the synthesis of (R,R)- and (S,S)-1,2-diaminocyclohexane. (C) 2000 Elsevier Science Ltd.
Chandrasekhar,Sekar,Singh
p. 10079 - 10083
(2007/10/03)

A diamine-exchange reaction of dihydropyrazines
Dihydropyrazines reacted with 1,2-diamines to form tetraazadecalins as intermediates, and then the reaction proceeded forward to dissociate into alternate dihydropyrazine and diamine, or backward to dissociate into the starting materials in certain equilibrium. The product distribution is controlled by diamine-exchange equilibrium reaction. The various equilibrium reactions were analyzed by NMR spectroscopy.
Yamaguchi, Tadatoshi,Ito, Shigeru,Iwase, Yukiko,Watanabe, Kenji,Harano, Kazunobu
p. 1677 - 1680
(2007/10/03)

Experimental and theoretical approach to hydrogen-bonded diastereomeric interactions in a model complex
Binding affinities of (R,R)-1,2-cyclohexanediamine (R) to (R,R)-1,2-cyclopentanediol (R5) and (S,S)-1,2-cyclopentanediol (S5) and to the corresponding cyclohexanediols (R6 and S6) have been measured in benzene and in CCl4 at 298 K by microcalorimetry, and unexpected differences between the diastereomeric complexes are observed. Long time scale (0.1 μs) molecular-dynamics simulations of the two smaller diastereomeric complexes, R/R5 and R/S5, in a simplified solvent model are reported. A direct free energy calculation gives results in good agreement with the experimental values measured in benzene for the first pair, but nearly identical results for the second pair, which is at variance with experiment. A systematic analysis of the dependence of simulation results on model parameters is performed, and no possibility is found to improve the enantioselectivity by parameter tuning. Other possible causes for discrepancies are specific solute-solvent or solvent-solvent interactions, electronic charge redistribution effects, or formation of clusters of more than two molecules. Owing to the long time scales reached, a well-converged picture of the dynamics is obtained, and the species present at equilibrium can be studied in detail. The average lifetime of the complex is found to be about 200 ps, whereas that of a hydrogen bond is only about 5 ps. Besides the unbound state, the dominant species observed in the simulations for both diastereomeric pairs are singly hydrogen-bonded complexes, with a clear preference for a O to N over the N to O hydrogen bond. Many other hydrogen-bonding patterns (bridged, double) are also observed in minor amounts.
Hünenberger, Philippe H.,Granwehr, Josef K.,Aebischer, Jean-Nicolas,Ghoneim, Nagwa,Haselbach, Edwin,Van Gunsteren, Wilfred F.
p. 7533 - 7544
(2007/10/03)

Diastereo- and enantioselective synthesis of vicinal diamines via aza-Michael addition to nitroalkenes
The asymmetric synthesis of protected 1,2-diamines 4 by aza-analogous Michael addition of (-)-(2S,3R,4R,5S)-1-amino-3,4-dimethoxy-2,5-bis(methoxymethyl)pyrrolid ine (ADMP) to nitroalkenes 1 in good overall yields and high enantiomeric excesses (ee = 93-96%) is described. The auxiliary constitutes a novel chiral equivalent of ammonia and is removed under reductive N-N bond cleavage with Raney nickel, which also reduces the nitro group. The absolute configuration was determined by NMR-spectroscopic methods and polarimetry.
Enders, Dieter,Wiedemann, Juergen
p. 1443 - 1450
(2007/10/03)

Sequential biocatalytic resolution of (±)-trans-cyclohexane-1,2-diamine. Chemoenzymatic synthesis of an optically active polyamine
Candida antarctica lipase-catalysed double monoaminolysis of dimethyl malonate by (±)-trans-cyclohexane-1,2-diamine allows the sequential resolution of the latter compound, affording an enantiopure bis(amidoester), (R,R)-3, which is subsequently transformed into an optically active polyamine, (R,R)-9.
Alfonso, Ignacio,Astorga, Covadonga,Rebolledo, Francisca,Gotor, Vicente
p. 2471 - 2472
(2007/10/03)

Kinetic resolution of chiral auxiliaries with C2-symmetry by lipase-catalyzed alcoholysis and aminolysis
Three cyclic diols, 1,2-cyclohexanediol (1), 1,3-cyclohexanediol (2), and 1,3-cyclopentanediol (3), two acyclic unsaturated diols, 1,5-hexadiene-3,4-diol (4) and 1,7-octadiyne-3,6-diol (5), and a cyclic diamine, 1,2-cyclohexanediamine (6), have been kinetically resolved in alcoholysis and aminolysis reactions, catalyzed by Candida antarctica component B lipase, using S-ethyl thiooctanoate or ethyl octanoate as acyl donors. Acceptable stereoselectivity was achieved in most cases. Acta Chemica Scandinavica 1996.
Mattson, Anders,Orrenius, Christian,Oehrner, Niklas,Unelius, C. Rikard,Hult, Karl,Norin, Torbjoern
p. 918 - 921
(2007/10/03)

Optical resolution method
The present invention provides three optical resolution methods. The first aspect comprises the steps of adding an optically active bifunctional resolving reagent to a bifunctional compound to form a liquid material, precipitating crystals therefrom, and treating the crystals and the liquid material separately with an acidic material, a basic material, or a basic material and an acidic material, to obtain a pair of enantiomers of an optically active bifunctional compound. The second aspect comprises an optical resolution method by which one necessary enantiomer of a pair of enantiomers in an optically active bifunctional compound is exclusively obtained. The third aspect comprises a method for racemizing one unnecessary enantiomer of a pair of enantiomers in an optically active bifunctional compound which is formed by the optical resolution method of the present invention.
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(2008/06/13)

Epimerization-Crystallization Method in Optical Resolution of 2,2'-Dihydroxy-1,1'-binaphthyl, and Kinetic Study
Optical resolution of 2,2'-dihydroxy-1,1'-binaphthyl (1) with (R,R)-1,2-cyclohexanediamine (2) in toluene yielded optically pure (R)-1 in a yield of 160percent based on the theoretical amount of the enantiomer contained in the racemate by selective crystallization of a less soluble complex, (R)-1*(R,R)-2, and epimerization of more soluble complex, (S)-1*(R,R)-2.Also optically pure (S)-1 was obtained with the same enantiomer of the resolving agent, (R,R)-2, in a yield of 154percent. (R,R)-1,2-Diphenyl-1,2-ethanediamine (3) was a suitable resolving agent for both 1 and 6,6'-dibromo-2,2'-dihydroxy-1,1'-binaphthyl.Kinetic study indicated that the reversible first-order rate constants for the epimerizations of (S)-1*(R,R)-2 and (S)-1*(R,R)-3 were larger than that for the racemization of (S)-1.The activation energy and frequency factor for the epimerization of (S)-1*(R,R)-2 were 109 kJ mol-1 K-1 and 3E10 s-1, respectively, and those for (S)-1*(R,R)-3 were 96 kJ mol-1 and 1E8 s-1, while those for the racemization of (S)-1 were 85 kJ mol-1 K-1 and 9E5 s-1, respectively.
Kawashima, Masatoshi,Hirata, Reiko
p. 2002 - 2005
(2007/10/02)