新轴手性N,N-Dioxide Biscarbolin衍生物催化酮亚胺的不对称硅氢化反应

以L-色氨酸为原料合成了5个伯酰胺结构的轴手性双咔啉N—O催化剂N2,N2'-二氧-9,9'-二甲基-3,3'-取代甲酰胺-β-双咔啉(4A~4E),并用于不对称催化酮亚胺的还原反应.结果表明,催化剂的催化转化率较高(80%~98%),立体选择性(e.e.值)较好,其中催化剂N2,N2'-二氧-9,9'-二甲基-3,3'-环己基甲酰胺-β-双咔啉(4B)的催化转化率达到了98%,e.e.值达68%.     

Complexation behaviour of a CT complex composed of 9,10-bis(3,5-dihydroxyphenyl)anthracene and viologen derivatives

A chiral charge-transfer (CT) complex was formed using achiral 9,10-bis(3,5-dihydroxyphenyl)anthracene (BDHA) as an electron donor and achiral 1,1′-dimethyl-4,4′-bipyridinium dichloride (MVCl₂) as an electron acceptor. This chiral CT complex can include n-alkyl alcohol molecules as guests. On the other hand, when 1,1′-diphenyl-4,4′-bipyridinium dichloride and 1,1′-dibenzyl-4,4′-bipyridinium dichloride were used as electron acceptors, achiral CT complexes without guests were formed. It was found that the chiral crystallisation of the BDHA/MVCl₂–CT host system was caused by steric and electric intermolecular interactions between host component molecules BDHA and MVCl₂ during crystallisation.     

Synthesis and enantiomer separation of a modified tris(2,2′-bipyridine)ruthenium(II) complex

The chiral [5-(4-hydroxybutyl)-5′-methyl-2,2′-bipyridine]-bis(2,2′-bipyridine)-ruthenium(II)-bis(hexafluoroantimonate) complex 3 was prepared and characterized by different NMR techniques and successfully separated into enantiomers by electrokinetic chromatography using anionic carboxymethyl-β-cyclodextrin as chiral mobile phase additive (CMPA). The optimum separation conditions were obtained with 40 mM borate buffer at pH 9.5 and 7.5 mg/mL of the chiral selector at 20°C.     

Convenient methods for the synthesis of highly functionalized and naturally occurring chiral allenes

A convenient two step procedure to access highly functionalized chiral allenes using chiral N-methylcamphanyl piperazine derivatives is described. In this transformation, chiral propargylamines are obtained in 79–96% yields with up to 99:1 dr by the CuBr catalyzed reactions of chiral piperazine derivatives with 1-alkynes and aldehydes containing functional groups, which are converted into chiral allenes in the presence of zinc bromide, affording the chiral allenes in 59–85% yields and with up to 99% ee. The antifungal agent Sapium japonicum and an allene precursor intermediate for the synthesis of the pheromone of the male dried bean beetle 15 are obtained in 72–78% yields and with up to 98% ee following this methodology.     

含光学活性联二萘酚基团可溶性高分子手性配体的合成及其不对称加成反应

不对称催化是有机化学研究的前沿领域和发展方向．近10年来,手性配体的研究得到了长足的发展,大量的小分子手性配体被报道,其中许多手性配体展示了优异的催化性能．但是由于昂贵的手性配体（金属催化剂）分离、回收和再利用的问题,从而限制了小分子催化剂的应用．因此,解决手性金属催化剂的分离与回收问题是不对称催化研究领域的一个热点问题．为了解决这一关键问题,国内外科学家从负载的角度出发已经成功地发展了众多的研究方法,无机负载法、交联高分子负载法、可溶性高分子负载法、树状大分子负载法等．许多负载的手性金属催化剂已经表现出优异的催化活性和高的对映选择活性．     

Asymmetric Synthesis and Characterization of Chiral 2,2′‐Diamino‐3,3′‐diethoxycarbonyl‐8,8′‐diphenyl‐1,1′‐biazulene

Abstract

rac‐2,2′‐Diamino‐3,3′‐diethoxycarbonyl‐8,8′‐diphenyl‐1,1′‐biazulene was synthesized from diethyl 2‐aminoazulene‐1,3‐dicarboxylate and was optically resolved into two enantiomers of S‐form and R‐form. The enantioselective oxidative couplings with two chiral amines [(?)‐sparteine and (R)‐(+)‐α‐methylbenzylamine] and ferric chloride catalyst, and the asymmetric couplings with two chiral oxovanadium(IV) complexes of ethyl 2‐amino‐4‐phenylazulene‐1‐carboxylate, easily yielded chiral 2,2′‐diamino‐3,3′‐diethoxycarbonyl‐8,8′‐diphenyl‐1,1′‐biazulene. Therefore, the introduction of two phenyl groups at the 8‐ and 8′‐postions of each azulene ring using phenyl magnesium bromide via an addition–oxidation–decarboxylation mechanism resulted in 1,1′‐biazulene forming a chiral C₂ axis.     

Synthesis of P,N-2,2′-biphenyl derivatives with central chirality

Enantiopure 2-(dicyclohexylphosphino)-1,1′-biphenyl derivatives substituted in the 2′-position by a chiral amino group were prepared. For the compound bearing an acyclic chiral chain, the key step was a Suzuki coupling between bromobenzeneboronic acid and N-Boc-iodoaniline whereas an aromatic nucleophilic substitution allowed the introduction of a chiral pyrrolidine in the 2′-position of the biphenyl backbone. The efficiency of the P,N-biphenyl pyrrolidine derivatives as ligands in Pd-catalyzed arylaminations compares well with that of DavePhos ligand.     

Catalytic Asymmetric Ring‐Opening Reactions of Aziridines with 3‐Aryl‐Oxindoles

A highly enantioselective ring‐opening alkylation reaction between 3‐aryl‐oxindole and N‐(2‐picolinoyl) aziridine has been realized for the first time. The reaction is efficiently mediated by a simple in‐situ‐generated magnesium catalyst and 3,3′‐fluorinated‐BINOL (BINOL=1,1′‐binaphthalene‐2,2′‐diol) has been identified as a powerful chiral ligand. Notably, the fluorine atom on the chiral ligand plays a key role in providing the desired chiral 3‐alkyl‐3‐aryl oxindoles with excellent enantioselectivities.     

A modular approach to a new class of phosphinohydrazones and their use in asymmetric allylic alkylation reactions

A group of five phosphino hydrazones with a pendant binaphthyl unit as a chiral modifier has been synthesized from non-racemic 2,2′-bis(bromomethyl)-1,1′-binaphthyl and 3,3′-diiodo-2,2′-bis(bromomethyl)-1,1′-binaphthyl as the key intermediates. Their efficiency as chiral ligands in palladium-catalyzed allylic alkylation reactions has been investigated showing up to 95% ee under optimized conditions. X-ray diffraction structures of mono- and dimeric Pd complexes are also reported.     

Synthesis of Chiral 2,5—Bis（oxazolinyl） thiophenes and Their Application as Chiral Shift Reagents for 1,1′—Bi—2—naphthol

A series of C2-symmetrical chiral 2,5-bis (4′-alkyloxazolin-2-yl) thiophenes (thiobox) have been synthesized from thiophene-2,5-dicarboxylic acid by sequential amidation with a chiral ethanolamine,conversion of hydroxyl to chloro group, and base-promoted oxazoline ring formation.As demonstrated by (-)-2,5-bis[4′-(S)-isopropyloxazolin-2′-yl] thiophene,these thiobox systems exhibited remarkable chirality recognition of 1,1′-bi-2-naphthol giving rise to pronounced shifts in the ^1H NMR signals of the latter axial chiral compound at the positions of C-3,C-4,C-5,and C-8.     

Catalytic Enantioselective 1,3‐Alkyl Shift in Alkyl Aryl Ethers: Efficient Synthesis of Optically Active 3,3′‐Diaryloxindoles

Reported is the first organocatalytic asymmetric 1,3‐alkyl shift in alkyl aryl ethers for the synthesis of chiral 3,3′‐diaryloxindoles using a chiral Brønsted acid catalyst. Preliminary results showed that each enantiomer of the 3,3′‐diaryloxindole, and a racemic mixture, showed different antiproliferative activities against HeLa cell lines by using an MTT assay.     

有机催化靛红衍生酮亚胺与噁唑酮的不对称Mannich型加成反应

研究了手性磷酸催化的靛红衍生酮亚胺与噁唑酮的不对称Mannich型加成反应, 以良好至优秀的收率(高达97%)、 对映选择性(高达99% e.e.)以及非对映选择性(均>20∶1 d.r.)得到一系列含噁唑酮骨架的手性3,3′-二取代氧化吲哚化合物. 该反应可以进行扩大化和衍生反应.     

Thin ferroelectric liquid crystal layers: mechanical stability and fast electro-optical response,connection between molecule design and surface properties

The storage of information after mechanical stimuli even without applied electrical field is based on the elastic properties of the ferroelectric liquid crystal (FLC) material and the anchoring energy. It is favourable for chiral molecules with extended length, such as 4,4′-di-substituted quaterphenyls and 4,4′-di-substituted quinquephenyls, which have in series-connected benzene rings, but not separated by bridging fragments. To obtain the required stability with a reasonable switching speed of about 50 μs 4,4′-di-substituted chiral quaterphenyls with two chiral centres on the same wing has been synthesised. Here, the switching is much faster compared to compounds with same quaterphenyl fragment, but only with one chiral centre.     

Synthesis of Novel Chiral Biphenylamine Ligand 6,6'‐Dimethoxy‐2,2′‐diaminobiphenyl

A new chiral ligand 6,6′‐dimethoxy‐2,2′‐diaminobiphenyl was successfully prepared from 3‐nitrophenol via iodination, Ullmann coupling, and reduction. The resolving reagent (2R, 3R)‐ or (2S,3S)‐2,3‐di (phenylaminocarbonyl)tartaric acid was prepared from commercially available tartaric acid in large scale and was used to resolve the racemic 6,6′‐dimethoxy‐2,2′‐diaminobiphenyl. The chiral 6,6′‐ dimethoxy‐2,2′‐diaminobiphenyl obtained was proved to be enantiomerically pure.     

联二萘胺及其苯甲酰衍生物的制备和手性拆分

合成了 1,1′ -联 - 2 -萘胺和 1,1′ -联 - 2 -萘胺双苯甲酰胺 .用红外光谱对产物结构进行了表征 .用高效液相色谱手性固定相法拆分了产物的对映异构体 ,考察了流动相组成对手性拆分的影响     

Synthesis and characterization of chiral polymer complexes incorporating polybinaphthyls,bipyridine, and Eu(III)

Chiral conjugated polymers P‐1 and P‐2 were synthesized by the polymerization of (S)‐3,3′‐diiodo‐2,2′‐bisbutoxy‐1,1′‐binaphthyl and (S)‐6,6′‐dibromo‐2,2′‐bisbutoxy‐1,1′‐binaphthyl, respectively, with 5,5′‐divinyl‐2,2′‐bipyridine through a Heck cross‐coupling reaction. Chiral polymer complexes P‐C‐1 and P‐C‐2 were obtained by the bipyridine chelating coordination of P‐1 and P‐2 with Eu(TTA)₃·2H₂O (where TTA is 2‐thenoyltrifluoroacetonate). Polymers P‐1 and P‐2 and polymer complexes P‐C‐1 and P‐C‐2 exhibited intense circular dichroism signals, with negative and positive Cotton effects in their circular dichroism spectra. The chiral polymers showed strong green‐blue fluorescence because of the efficient energy migration from the extended π‐electronic structure of the conjugated polymer main to the chiral binaphthyl core. The chiral polymer complexes could have not only polymer fluorescence but also the characteristic fluorescence of Eu(III) (⁵D₀→⁷F₂) at a different excited wavelength. These kinds of chiral polymer complexes incorporating polybinaphthyls, bipyridine, and Eu(III) moieties are expected to provide an understanding of the relationship between the structure and properties of chiral polymer complexes. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 650–660, 2007     

One-Handed Helical Tubular Ladder Polymers for Chromatographic Enantioseparation**

Defect-free one-handed contracted helical tubular ladder polymers with a π-electron-rich cylindrical helical cavity were synthesized by alkyne benzannulations of the random-coil precursor polymers containing 6,6′-linked-1,1′-spirobiindane-7,7′-diol-based chiral monomer units. The resulting tightly-twisted helical tubular ladder polymers showed remarkably high enantioseparation abilities toward a variety of chiral hydrophobic aromatics with point, axial, and planar chiralities. The random-coil precursor polymer and analogous rigid-rod extended helical ribbon-like ladder polymer with no internal helical cavity exhibited no resolution abilities. The molecular dynamics simulations suggested that the π-electron-rich cylindrical helical cavity formed in the tightly-twisted tubular helical ladder structures is of key importance for producing the highly-enantioseparation ability, by which chiral aromatics can be enantioselectively encapsulated by specific π-π and/or hydrophobic interactions.     

Photocontrolled Phase Transitions and Reflection Behaviors of Smectic Liquid Crystals by a Chiral Azobenzene

The photocontrolled phase transitions and reflection behaviors of a smectic liquid crystal, 4‐octyl‐4′‐cyanobiphenyl (8CB), tuned by a chiral azobenzene, are systematically investigated. For the smectic 8CB doped with the chiral azobenzene (1R)‐(?)‐4‐n‐hexyl‐4′‐menthylazobenzene (ABE), the initial smectic phase can be switched to cholesteric and then to isotropic upon UV irradiation due to the trans‐to‐cis photoisomerization of ABE; however, no reflection band is observed. For the smectic 8CB doped with ABE and the chiral agent (S)‐(?)‐1,1′‐binaphthyl‐2,2′‐diol (BN), a reflection band located in the short‐wavelength infrared region is observed, which disappears after further UV irradiation. For the smectic 8CB doped with ABE and a chiral agent with higher helical twisting power, (S)‐2,2′‐methylendioxy‐1,1′‐binaphthalene (DBN), a phototunable system with cholesteric pitch short enough to reflect visible light is demonstrated. With a given concentration of the chiral dopant DBN, a reversible reflection color transition is realized tuned by the isomerization of azobenzene. The reverse phase transition from isotropic to cholesteric and then to smectic can be recovered upon visible irradiation. The photocontrolled phase transitions in smectic liquid crystals and the corresponding changes in reflection band switched by photoisomerization of azobenzene may provide impetus for their practical application in optical memories, displays, and switches.     

Lewis‐Base‐Mediated Diastereoselective Silylations of Alcohols: Synthesis of Silicon‐Stereogenic Dialkoxysilanes Controlled by Chiral Aryl BINMOLs

In the past years, stereoselective functionalizations of hydroxyl groups of alcohol substrates with chlorosilanes leading to silyl ether formation have evolved from a functional‐group protection to an enantioselective synthetic strategy. This work comprises a controlled desymmetrization of dichlorosilanes by using a family of structurally specific chiral diols, chiral 1,1′‐binaphthalene‐2‐α‐arylmethanol‐2′‐ol (Ar‐BINMOL). This process led to the facile construction of silicon‐stereogenic organosilicon compounds with high yields and good diastereoselectivities. In addition, the diasteroselective silylation of chiral diols might not only be of interest for the development of highly stereoselective nucleophilic silylation, but also shed light on the construction of novel chiral phosphine ligands bearing a silicon‐stereogenic center.     

HPLC separation of the enantiomers of racemic benzergoline derivatives on a chiral binaphthalene covalently bonded to silica gel

A novel chiral stationary phase (CSP) derived from the atropisomeric enantiomer S-3,3′-dicarboxy-2,2′-dihydroxy-1,1′-binaphthyl (S-DDBN) has been synthesized and its use for the separation of enantiomers demonstrated. The chiral selector is covalently bonded to amino-functionalized silica gel, thus enabling the use of alcohols as mobile phases. Good chiral discrimination was obtained for the pharmacologically interesting class of benzergoline derivatives which act as selective dopamine D₁ receptor agonists. This paper reports the successful separtion of fifteen structurally related benzergoline racemates with separation factors up to 3.5. The influence of small differences in molecular structure on chiral discrimination was examined.