Crystal Structure of (R)-3,3′-Bis(benzyloxymethyl)-1,1′-bi-2,2′-naphthol and Its Applications in Enantioselective Lewis Acid Catalyzed Addition of Diethylzinc to Aldehydes

The title compound (R)-3,3′-bis(benzyloxymethyl)-1,1′-bi-2,2′-naphthol (R)-3 has been synthesized through the deprotection of MOM group by iPrOH/HCl in 83% isolated yield and the suitable single crystals for X-ray diffraction were obtained by recrystallization at room temperature from the mixture solvents. Crystallographic data for (R)-3: C36H30O4, Mr = 526.60, triclinic, space group P1, a = 10.057(6), b = 11.934(7), c = 12.314(6) , α = 85.52(2), β = 70.245(13), γ = 76.554(11)o, Z = 2, V = 1352.8(13)3, Dc = 1.293 g/cm3, F(000) = 556, R = 0.0745, wR = 0.1933 and μ(MoKα) = 0.083 mm-1. The title compound (R)-3 was found to be effective in the enantioselective addition of diethylzinc to aldehydes both in the presence and absence of Ti(OiPr)4. In the latter case, (R)-3 showed much higher catalytic activity and enantioselectivity than (R)-BINOL′s.     

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．     

Crystal Structure of （R）-3,3＇- Bis （b enzyloxymethyl）- 1,1 ＇-bi- 2,2＇-naphthol and Its Applications in Enantioselective Lewis Acid Catalyzed Addition of Diethylzinc to Aldehydes

The title compound (R)-3,3'-bis(benzyloxymethyl)-1,1'-bi-2,2'-naphthol (R)-3 has been synthesized through the deprotection of MOM group by iprOH/HC1 in 83% isolated yield and the suitable single crystals for X-ray diffraction were obtained by recrystallization at room temperature from the mixture solvents. Crystallographic data for (R)-3: C36H30O4, Mr = 526.60,triclinic, space group P1, a = 10.057(6), b = 11.934(7), c = 12.314(6) (A), α = 85.52(2), β =70.245(13), γ = 76.554(11)°, Z= 2, V= 1352.8(13) (A)3, Dc = 1.293 g/cm3, F(000) = 556, R = 0.0745,wR = 0.1933 and μ(MoKα) = 0.083 mm-1. The title compound (R)-3 was found to be effective in the enantioselective addition of diethylzinc to aldehydes both in the presence and absence of Ti(OiPr)4. In the latter case, (R)-3 showed much higher catalytic activity and enantioselectivity than (R)-BINOL's.     

Dendritic BINOL ligands for asymmetric catalysis: effect of the linking positions and generations of the dendritic wedges on catalyst properties

Three types of new chiral BINOL ligands (2, 3 and 4) bearing dendritic wedges have been synthesized through coupling reaction between 3-hydroxymethyl-2,2′-bis(methoxymethyl)-1,1′-binaphthol (7), 6,6′-dihydroxymethyl-2,2′-bis(methoxymethyl)-1,1′-binaphthol (12), 6-hydroxymethyl-2,2′-bis(methoxymethyl)-1,1′-binaphthol (15) and Fréchet-type polyether dendritic benzyl bromide, followed by deprotection of methoxymethyl groups by ⁱPrOH/HCl, respectively. These new ligands obtained were assessed in enantioselective Lewis acid-catalyzed addition of diethylzinc to benzaldehyde. Compared to the enantioselectivity observed with dendrimer 1 bearing the dendritic wedges at 3,3′-positions of the binaphthyl backbone, higher enantioselectivity for all these ligands was observed. Difference in the effect of linking positions and generations on enantioselectivity and/or activity for all three kinds of dendritic ligand-derived catalysts was observed. Among these dendritic ligands, (R)-3/Ti(IV) catalyst with the dendritic wedges at 6,6′-positions of BINOL gave the highest enantioselectivity (up to 87% ee).     

Facile optical resolution of tert-butanethiosulfinate by molecular complexation with (R)-BINOL and study of chiral discrimination of the diastereomeric complexes

An important synthon, tert-butanethiosulfinate (2), has been effectively resolved by forming molecular complexes with (R)-2,2'-dihydroxy-1,1'-binaphthyl (BINOL, 3) in high enantioselectivity (>99 % ee). The present procedure represents the first example of the resolution of thiosulfinate. The mechanism of chiral discrimination is discussed in terms of molecular recognition based on IR and Xray analyses of the diastereomeric complexes during the resolution. In the less-soluble complex, (R)-3 and (R)-2 self-assembled as a linear supramolecule; however, in the more-soluble complex, (R)-3 and (S)-2 formed a simple bimolecular complex by one stronger hydrogen bond. Hydrogen bonding is the major driving force for effective resolution.     

新型树状结构手性联二萘酚衍生物的合成及催化性能研究

报道了树状结构的手性联二萘酚(BINOL)配体的合成及其在二乙基锌对醛的不对称加成反应中的应用.(R)-2,2′-二羟基-1,1′-联萘-3,3′-二羧酸与末端为氨基的Frechet聚芳醚型树状分子经缩合反应,以中等产率得到0～3代的树状分子配体,用¹HNMR,IR和MALDI-TOF质谱进行了结构表征.这些树状手性配体与Ti(OPrⁱ)₄在无水甲苯溶液中形成的配合物是二乙基锌对醛不对称加成反应的高效催化剂,树状分子载体的体积对催化剂的对映选择性没有明显的影响.以邻氯苯甲醛为底物时,反应的对映选择性随树状分子代数的增加而有所提高.     

Highly anti-selective asymmetric aldol reactions using chiral zirconium catalysts. Improvement of activities, structure of the novel zirconium complexes, and effect of a small amount of water for the preparation of the catalysts

Catalytic asymmetric aldol reactions of silyl enol ethers with aldehydes (Mukaiyama aldol reactions) have been performed using novel chiral zirconium catalysts. The reactions proceeded in high yields under mild conditions, and anti-adducts were obtained in high diastereo- and enantioselectivities. The catalysts were first prepared from zirconium(IV) tert-butoxide (Zr(O(t)Bu)(4)), (R)-3,3'-diiodo-1,1'-binaphthalene-2,2'-diol ((R)-3,3'-I(2)BINOL), a primary alcohol, and a small amount of water. It was revealed that the primary alcohol played an important role in completing the catalytic cycle and that a small amount of water was essential for obtaining high selectivities. Moreover, activities of the chiral zirconium catalysts were enhanced by using new ligands, (R)-3,3'-I(2)-6,6'-X(2)BINOL (X = Br, I, C(2)F(5)), and it has been shown that even aldol reactions of less reactive substrates proceeded smoothly using the novel zirconium catalysts. Finally, NMR studies of these catalysts were performed, which suggested that the catalyst would form a dimeric structure and that the water affected the catalyst formation.     

含金刚烷基团的新型手性单齿亚磷酸酯配体的合成及其在不对称1,4-共轭加成反应中的应用

以轴手性的BINOL/H8-BINOL(BINOL为联苯酚)和大位阻的金刚烷酰氯为原料,合成了系列新型手性单齿亚磷酸酯配体,并应用于Cu催化的二乙基锌对环烯酮的不对称1,4.共轭加成反应中.结果表明,配体结构中部分氢化的2,2'-(1,1'-联萘基)亚磷酸酯单元和金刚烷基团,有助于改善反应的对映选择性,对映选择性最高可...     

The synthesis of dendritic BINOL ligands and their applications in the enantioselective Lewis acid catalyzed addition of diethylzinc to aldehydes

Novel dendritic chiral BINOL ligands have been synthesized through coupling of MOM-protected 3,3′-dihydroxymethyl-binaphthol with Fréchet-type polyether benzyl bromide dendrons followed by deprotection of the MOM groups using TsOH. These dendritic chiral BINOL ligands were found to be effective in the enantioselective addition of diethylzinc to benzaldehyde both in the presence and absence of Ti(O-iso-Pr)₄. The enantioselectivity decreased with increasing generation in both cases. In the latter case, the dendritic chiral BINOL ligands showed much higher catalytic activity and enantioselectivity than BINOL.     

The synthesis of silica-supported chiral BINOL: Application in Ti-catalyzed asymmetric addition of diethylzinc to aldehydes

Chiral BINOL was covalently anchored on two different pore sized mesoporous silica (SBA-15 (7.5 nm) and MCF (14 nm)). These heterogenized ligands were used in Ti-catalyzed asymmetric addition of diethylzinc to aldehydes. High catalytic activity with excellent enantioselectivity (up to 94% ee) for secondary alcohols was achieved using MCF supported chiral BINOL under heterogeneous reaction conditions. Good to excellent enantioselectivity (ee, 68–91%) was also achieved with various small to bulkier aldehydes. The MCF supported catalyst was reused in multiple catalytic runs without loss of enantioselectivity.     

Synthesis and structures of (R)-cyclopentadienyl-binaphthoxy titanium(IV) complexes and catalytic properties for olefin polymerization

Two new chiral pre-ligands, (R)-3,3'-bis(tetramethylcyclopentadienyl)-2,2'-bismethoxy-1,1'-bisnaphthalene (1) and (R)-3-tetramethylcyclopentadienyl-2,2'-bismethoxy-1,1'-bisnaphthalene (2), were synthesized by reaction of (R)-3,3'-dilithium-2,2'-bismethoxy-1,1'-bisnaphthalene with 2,3,4,5-tetramethyl-2-cyclopentenone at room temperature. Treatment of the pre-ligands 1 and 2 with butyllithium and Me(3)SiCl first, and subsequently with TiCl(4) (2 and 1 equiv for 1 and 2, respectively) afforded a binuclear complex (R)-3,3'-bis[(tetramethylcyclopentadienyl)trichlorotitanium]-2,2'-bismethoxy-1,1'-bisnaphthalene (3) and a mononuclear complex (R)-3-(tetramethylcyclopentadienyl)trichlorotitanium-2,2'-bismethoxy-1,1'-bisnaphthalene (4) in moderate yields. Complexes 3 and 4 were further converted into constrained geometry complexes (R)-1,1'-bis{2,2'-naphthoxy-3,3'-bis[(tetramethylcyclopentadienyl)dibromotitanium]} (5) and (R)-1-(2-naphthoxy)-1'-(2'-naphthol)-3-(tetramethylcyclopentadienyl)dibromotitanium (6) by treatment with BBr(3). The pre-ligands 1 and 2 were characterized by (1)H and (13)C NMR and high resolution mass spectroscopy (HRMS), and the new titanium complexes 3-6 were characterized by (1)H and (13)C NMR and elemental analyses. Molecular structures of 4, 5, and 6 were determined by single-crystal X-ray diffraction analysis. Complexes 4, 5, and 6 all have a pseudo-octahedral coordination environment and adopt a three-legged piano stool geometry around the titanium atom in their solid state structures. When activated with Al(i)Bu(3) and Ph(3)CB(C(6)F(5))(4), the chiral complexes 5 and 6 show moderate catalytic activities for propylene, 1-hexene, and 5-ethylidene-2-norbornene (ENB) polymerization and ethylene/1-hexene copolymerization. The polymers produced by the chiral 5/(i)Bu(3)Al/Ph(3)CB(C(6)F(5))(4) catalyst system from the 1-hexene, and ENB polymerization and ethylene/1-hexene copolymerization with high comonomer contents exhibit optical activity.     

Asymmetric Meerwein-Ponndorf-Verley reduction catalyzed by a new type of chiral binaphthol-samarium complex

A new type of chiral 1,1'-binaphthol(BINOL) derived samarium complex, preparedfrom (R)- or (S)-BINOL and SmCl3, serves as an enantioselective catalyst for the Meerwein-Ponndorf-Verley (MPV) reduction in the presence of Molecular Sieves 4A(MS 4A). Moderate enantioselectivity was obtained. Kinetic studies show slight decrease of the enantiomeric excess with the conversion.     

Synthesis of Chiral Phosphorus Reagents and Their Application in Combination With Lewis Acid as a Cocatalyst in Morita–Baylis–Hillman Reaction

Abstract

Two novel chiral thiophosphoramides and two chiral phosphoramidites were synthesized starting from (S)-α-phenylethylamine and (R)-(+) or (S)-(?)-1,1′-Bi-2-naphthol (BINOL), respectively, and their application in combination with Lewis acid as cocatalysts in asymmetric Morita–Baylis–Hillman (MBH) reaction was investigated. Dramatic rate acceleration (the corresponding adducts were obtained in fair to excellent chemical yield within 15 min–5 h) was observed in these chiral phosphorus reagents/Lewis acid cocatalyzed MBH reaction between 4-nitrobenzaldehyde and activated alkenes, and in one case, moderate enantioselectivity was achieved (the corresponding adduct's ee value is 44%).     

Construction of Optically Active Quaternary Propargyl Amines by Highly Enantioselective Zinc/BINOL‐Catalyzed Alkynylation of Ketoimines

A general and efficient method for the highly enantioselective alkynylation of ketoimines through a zinc/1,1′‐bi‐2‐naphthol (BINOL)‐catalyzed process has been developed. A variety of ketoimines, including α‐fluoroalkyl α‐imine esters, α‐aryl α‐imine esters, and trifluoromethyl aryl ketoimines, are applicable and provide their corresponding quaternary propargyl amines in excellent yields with high ee values (up to 99 % ee). Both the steric and electronic effects of substituents at the 3,3′ positions of BINOL are critical for the reaction efficiency and enantioselectivity. To demonstrate the usefulness of the method, (R)‐α‐CF₃ α‐proline has been prepared in a highly efficient manner. The notable features of this protocol are its broad substrate scope, high reaction efficiency (up to 99 %) and enantioselectivity (up to 99 % ee), low catalyst loading (5 mol % of BINOL derivative), and mild reaction conditions.     

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.     

3,3'-二取代联二萘酚硫脲催化合成4H-吡喃衍生物

合成了3种3,3′-二取代BINOL轴手性硫脲类催化剂(3a~3c),并成功地将其应用于催化不对称Knoevenagel-Micheal的串联反应。结果表明,以CH2Cl2为溶剂、3a为催化剂各种取代芳香醛与丙二腈和1,3-环己二酮在25℃下反应得到4H-吡喃衍生物,产率可达98%,对映选择性高达94%。     

Facile Synthesis of Chiral Conjugated Polymer Based on BINOL Skeleton

The study of polymer supported chiral catalysts has attracted very extensive attention inrecent years'. The intrinsic advantages of these catalysts in organic synthetic chemistryare that they can be separated with the products by simple filtration. Traditionally,polymer chiral catalysts are prepared by allaching chiral ligand to sterically irregularpolymer backbone2. In this system, the catalytic sites are randomly oriented along thepolymer chain which makes it very difficult to systematically…     

5-L-孟氧基4-苄氨基丁烯内酯的不对称合成和晶体结构研究

温和条件下,苄胺与手性合成子5-(L)-孟氧基3-溴-2(5)呋喃酮通过串联的不对称迈克尔加成/分子内消除反应合成了一种新手性化合物:5-L-孟氧基-4-苄胺基丁烯内酯。产物经过IR、1H-NMR、MS谱学表征,并经X-ray单晶衍射测定了其结构。新化合物属于正交晶系,P212121空间群,a=5.2945(4),b=14.2829(10),c=26.0769(18),Mr=343.45,Z=4,V=1972.0(2)3,Dc=1.157g/cm3,μ(MoKα)=0.076mm-1,F(000)=744,R=0.0387,wR=0.0880。     

Fluorescence properties of (R)- and (S)-[1,1′-binaphthalene]-2,2′-diols solutions and their complexes with cyclodextrins in aqueous medium

Steady-state and time-resolved fluorescence techniques were used to study (R)- and (S)-[1,1′-binaphthalene]-2,2′-diol (1,1′-binaphthol or BINOL) dilute solutions of different polarity solvents, as well as their inclusion complexes with α- and βcyclodextrins (CDs) in water. BINOLs in dilute water solutions exhibited a surprisingly high fluorescence anisotropy that was explained as being due to the formation of fairly large order π–π stacking aggregates in aqueous polar media. Stoichiometries, formation constants and the changes of enthalpy and entropy upon inclusion were also obtained by measuring the variation of the fluorescence intensity with [CD] and temperature. Results agree with the formation of 1:1 stoichiometry complexes, but the association constants are rather low and very similar for both enantiomers. Molecular mechanic calculations in the presence of water were employed to study the formation of BINOL complexes with both α- and βCDs. For the most stable structures of any of the complexes only a small portion of the guests, in agreement with thermodynamics parameters and quenching experiments, penetrates inside the CD cavities. Driving forces for 1:1 inclusion processes may be dominated by non-bonded van der Waals host:guest interactions. The low guest:host binding constants and poor enantioselectivity of α- and βCDs for BINOLS may be a consequence of the BINOL aggregation in water.     

A chiral porous metal-organic framework for highly sensitive and enantioselective fluorescence sensing of amino alcohols

A highly porous and fluorescent metal-organic framework (MOF), 1, was built from a chiral tetracarboxylate bridging ligand derived from 1,1'-bi-2-naphthol (BINOL) and a cadmium carboxylate infinite-chain secondary building unit. The fluorescence of 1 can be effectively quenched by amino alcohols via H-bonding with the binaphthol moieties decorating the MOF, leading to a remarkable chiral sensor for amino alcohols with greatly enhanced sensitivity and enantioselectivity over BINOL-based homogeneous systems. The higher detection sensitivity of 1 is due to a preconcentration effect by which the analytes are absorbed and concentrated inside the MOF channels, whereas the higher enantioselectivity of 1 is believed to result from enhanced chiral discrimination owing to the cavity confinement effect and the conformational rigidity of the BINOL groups in the framework. 1 was quenched by four chiral amino alcohols with unprecedentedly high Stern-Volmer constants of 490-31200 M(-1) and enantioselectivity ratios of 1.17-3.12.