Chiral transfer amidst one-dimensional linear polymers and twodimensional network covalent organic frameworks:Striking a fine balance between helicity and crystallinity

The current landscape of chiral covalent organic frameworks(COFs)predominantly centered on constructing asymmetric molecular-scale chirality,often introducing an inherent contradiction to the COF symmetry and limiting diversity.Herein,we overcome these challenges by achieving chiral transfer between one-dimensional(1D)imine linear polymers(LPs)and two-dimensional(2D)networkβ-ketoenamine COFs composed of achiral monomers.We successfully synthesize several 1D imine LPs with mesoscopic helical chirality,comprising achiral C2-symmetric terephthalaldehyde and diamine linkers in a chiral supramolecular transcription system.Leveraging the irreversible tautomerism mechanism within the linker replacement approach,terephthalaldehyde(TPA)units in these helical 1D LPs are substituted with C3-symmetric 1,3,5-triformylphloroglucinol(TP),yielding the corresponding 2D networkβ-ketoenamine COFs.Crystallinity and helicity of the resultantβ-ketoenamine COFs intimately hinge on reaction conditions,including the aldehyde stoichiometry of Tp and TPA,as well as the quantity and concentration of the catalyst employed.Under optimized conditions,the nucleation and growth were precisely governed,achieving a harmonious equilibrium of crystallinity and helicity within the generated 2D networkβ-ketoenamine COFs,even with covalent bond rupture,recombination,and topological transition(from[C2+C2]to[C3+C2]).Impressively,the ground state chirality inherent to helical 1D LPs seamlessly transfers to helical 2D networkβ-ketoenamine COFs.This study not only offers new perspectives on the development of chiral functional COFs,but also provides fresh insights into the precise control of COFs'microscopic morphology.

Chiral transfer-dictated self-assembly of chiral block copolymers

Chiral structures not only exist in nature widely,they also emerge in artificial systems,attracting myriad attentions due to their excellent mechanical,optical,electrical,and magnetic properties.Self-assembly of chiral block copolymers(BCPs*),where at least one block consists of chiral centers,represents a facile strategy to form helical/spiral/network structures with a controlled chirality.Usually,morphological chirality of BCP*assemblies was closely associated with molecular and conformational chirality of the chiral block.Generally,chiral assemblies arose from molecular chirality of BCPs*,transferring up in the assembly process and dictated the chirality at a higher hierarchical level.In contrast,notwithstanding similar assemblies could be observed from achiral BCPs under certain conditions,both left-and right-handed ones were usually observed simultaneously without a preference.Moreover,unique feature of BCPs*to access to controllable chiral assemblies affords an opportunity to prepare advanced functional materials.Herein,we dedicated a review on assembly of BCPs*into chiral assemblies in bulk/films,selective solvents,and confined spaces.The chiral transfer process in these assembly scenarios were discussed and highlighted as a key contributor to morphological chirality.Functionalities and representative applications of BCP*assemblies were also described,followed by present challenges and future prospects of BCP*self-assembly.

Novel Chiral PNNP-Ru Complexes:Synthesis and Application in Asymmetric Transfer Hydrogenation of Ketones

The efficient catalytic systems generated in situ from RuCl2（PPh3）3 and chiral ligands N,N-bis[2-（di-o-tolylphosphino）-benzyl]cyclohexane-1,2-diamine（2） were employed for asymmetric transfer hydrogenation of aromatic ketones, giving the corresponding optically active alcohols with high activities（up to 99% conversion） and excellent enantioselectivities（up to 96% e.e.） under mild conditions. The chiral ruthenium（Ⅱ） complex （R,R）-3 has been prepared and characterized by NMR and X-ray crystallography.

New Chiral Metal Cluster Systems for Catalytic AsymmetricSyntheses of Chiral Alcohols

The efficient chiral Ru 3(CO) 12 systems were prepared in situ from Ru 3(CO) 12 and various chiral diimino-or diamino-diphosphine tetradentate ligands. The systems have been used for the asymmetric transfer hydrogenation of propiophenone in 2-propanol, leading to 1-phenyl-1-propanol in a 98% yield and 96% e.e. The IR study suggests that the carbonyl hydride anion [HRu 3(CO) 11]- most probably exists as a principal species under the reaction conditions. The high chiral efficiency may be due to the synergetic effect produced by the neighboring ruthenium atoms and a special chiral micro-environment involving the polydentate ligand and the Ru 3 framework.

Enantioselective Transfer Hydrogenation of Aromatic Ketones Catalyzed by New Diaminodiphosphine Ru(Ⅱ) Complexes

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The Nature of the True Catalyst in Transfer Hydrogenation with Alcohol Donors Using (arene)₂Ru₂Cl₄(II)/TsDPEN Precursor

The widespread precatalyst (prepared in-situ or ex-situ) (arene) RuTsDPEN advocated for highly effectual asymmetric transfer hydrogenation (ATH) reactions with 2-propanol as hydrogen donor at ambient conditions, is proven to be unstable under the strong reducing conditions prevailing in the reaction mixtures (blend of alcohol and a base such as KOH). We assert that the true catalysts are the ruthenium metal nanoclusters formed swiftly under the reducing conditions of these systems. The TsDPEN ligand plays a critical role in the generation and formatting of the active catalyst including wreaking chiral properties to the so formed catalytic nanoparticles. Kinetic measurements, NMR, UV-visible spectroscopy, circular dichroism (CD) and TEM analyses corroborate this argument.

Chiral metal nanocluster within nanoarchitecture of fullerene C_(60):Chirality transfer and improvement of nonlinear optical property

Interaction between heterogeneous,nanometer-sized building blocks(NSBBs)is fascinating from viewpoints of both structures and functions.We report the co-assembly of fullerene C_(60) and a chiral silver nanocluster(Ag_(6)),which yields C_(60) nanoarchitecture decorated with a small amount of Ag_(6).While Ag_(6) exhibits circular dichroism(CD)signal mainly in the ultraviolet(UV)region,the signal of the C_(60)-Ag_(6) hybrid extends to visible region(over 700 nm).Up to five pairs of CD signals were distinguished,which match well with the absorption of the C_(60) crystal.The successful chirality transfer from the guest of Ag_(6) to C_(60)-dominated supramolecular system indicates that the“sergeants and soldiers”effect is valid in architectonics of NSBBs.In addition,the doping of Ag_(6) leads to pronounced nonlinear optical response,paving a new way for the development of chiral optical materials.

贵金属-壳聚糖催化苯乙酮不对称转移加氢反应

将天然手性高分子聚合物壳聚糖(CS)负载到S iO2上后,再络合M(Pd、P t、Pu和Ph)金属,制得了多相手性加氢催化剂M-CS-S iO2。在空气氛围下,以异丙醇为氢源,考察了M-CS-S iO2对苯乙酮不对称催化氢转移加氢反应的催化活性。研究了活性金属(Pd、P t、Rh和Ru)、载体(ZSM-5、β、M CM-41、S iO2),及钯的前驱物对多相手性加氢催化剂性能的影响。结果表明:Pd-CS-S iO2对苯乙酮不对称转移加氢反应具有较好的催化加氢性能和对R-1-苯乙醇的对映选择性;Pd的前驱物对Pd-CS-S iO2的催化活性和对映选择性的影响较小;载体对Pd催化剂的催化活性和对映选择性的影响很大;在苯乙酮不对称转移加氢反应中,Pd-CS-β分子筛对R-1-苯乙醇的对映体过量值可达到65.7%。

含松香骨架的新型手性季铵盐相转移催化剂的合成及其在不对称环氧化反应中的应用

以天然松香为原料合成了4个新型手性季铵盐类相转移催化剂,并用于催化不对称查尔酮环氧化反应,发现这类手性相转移催化剂可以有效地催化查尔酮的不对称环氧化,环氧化产物ee最高达20%.

手性相转移催化剂及其在不对称催化反应中的应用

综述了手性季铵盐、手性冠醚以及其它新型手性相转移催化剂的制备及其在各种不对称相转移催化反应如烷基化反应、Michael加成反应、Aldol反应、Mannich反应、氧化反应及还原反应中应用的最新进展。

6-氟-L-多巴合成及其对映纯度测定的研究

目的 合成 6 氟 L 多巴 (6 FDOPA) ,并测定其对映纯度。方法 以硝基藜芦醛 (2 )为原料 ,经亲核取代、还原碘化、手性相转移催化烷基化等多步反应得新化合物 2 (2 氟 4,5 二甲氧苄基 ) N (二苯基甲叉 )甘氨酸叔丁酯(8) ,8经水解反应制备终产物 6 FDOPA ,用手性流动相和反相C1 8柱的HPLC法测定其对映纯度。结果 合成 6 氟 L 多巴总反应时间少于 90min ,总产率约为 33% ,对映纯度大于 95 %。结论 可大量合成 6 FDOPA ,使自动合成 6 [1 8F] L 多巴成为可能。为 6 [1 8F] L

基于天然氨基酸的双环手性季铵盐相转移催化剂的合成及催化性能研究

以L-脯氨酸及L-羟基脯氨酸为原料合成了4个新型手性季铵盐类相转移催化剂,并用于催化不对称查耳酮环氧化反应,高产率得到相应环氧化合物,ee最高达9％。

使用手性相转移催化剂不对称诱导(±)-1,3-二甲基-5-甲氧基氧化吲哚的碳烷基化反应

报道了９种手性季铵盐催化１，３－二甲基－５－甲氧基氧化吲哚的不对称碳烷基化反应。通过研究催化剂的不同结构、溶剂、温度、碱对产物光学活性的影响，讨论了不对称诱导机理。确定了产物绝对构型和对映体过量。

6-氟-L-多巴的不对称合成(英文)

目的 :合成 6 氟 L多巴 (FDOPA)。方法 :以硝基藜芦醛为原料 ,经亲核取代、还原碘化、手性相转移催化烷基化、水解及HPLC纯化等步骤制备FDOPA ,用手性流动相结合反相C18柱的HPLC法测定其对映纯度。结果 :合成FDOPA总反应时间 (不包括催化剂的合成时间 )少于 90min ,总产率约为 33 % ,对映纯度大于 95 %。结论 :手性相转移催化烷基化法可以高选择性地合成FDOPA。本研究为 6 [18F] L 多巴及其它

SiO_2负载壳聚糖-Pd多相手性加氢催化剂

将天然手性高分子聚合物壳聚糖负载到二氧化硅上,再负载活性金属制得了多相手性加氢催化剂 (M-CS-SiO2),用元素分析、FT-IR和XRD测试技术对催化剂进行了表征,并在空气氛围下,考察了对苯乙酮不对称氢转移加氢反应的催化活性和产物的对映选择性。结果表明,活性金属组分对手性催化剂的性能有较大的影响,在研究的Pd、Pt、Rh和Ru催化剂中,Pd催化剂具有最好的催化活性和R-1-苯乙醇的对映选择性, 不同的Pd前驱物对催化剂的性能影响较小。在Pd-CS-SiO2催化的苯乙酮不对称加氢反应中,氢源和反应温度对催化剂的活性和产物的对映选择性影响较大,甲酸铵和甲酸钠是优良的氢源。以甲酸铵为氢源时,少量水的存在对苯乙酮不对称转移加氢反应有抑制作用;以甲酸钠为氢源时,添加质量分数为5％的水时,产物的对映选择性可增加8．4％。在80℃反应时,产物R-1-苯乙醇的对映选择性达到69％。

新型手性相转移催化合成L-苯丙氨酸

提出了一种新型的手性催化合成L 苯丙氨酸的方法。以甘氨酸为原料 ,在保护氨基和羧基的条件下合成苯亚甲氨基乙酸乙酯 ,然后与卤代烃在手性相转移催化剂L 肉碱的催化下反应生成手性烃化产物。经酸性水解得到L 苯丙氨酸 ,产率 4 0 .1%旋光纯度在 5 3.5 %。

新的反应控制的手性相转移催化剂的合成

合成了一种新的反应控制的手性相转移催化剂[Ph(CH3)C·HN(CH3)3]9PW9O34,第一次将手性引入到反应控制的相转移催化系统的催化剂中,这为扩展该催化系统的应用(从非手性环氧化到手性环氧化)提供了可能性.对查尔酮的初步环氧化反应实验证明,该催化剂具有反应控制的特点.

具有C_2-对称性的手性二茂铁Schiff碱的合成、表征及其在不对称氢转移反应中的应用

首次报道了（１Ｒ，２Ｓ）－二苯基乙二胺，（１Ｓ，２Ｒ）－环已二胺，（Ｒ）－（＋）－联二萘胺与甲酰基二茂铁反应，生成三个具有Ｃ２－对称性的手性二茂铁Ｓｃｈｉｆｆ碱１，２，３，通过ＩＲ，＾１ＨＮＭＲ，元素分析和旋光度测定确定其结构。并且将其作为配体，分别与Ｒｈ，Ｉｒ，Ｒｕ等过渡金属“原位”形成配合物对苯乙酮的不对称氢转移反应进行也研究，考察了反应条件，配体结构对反应和产物的构型的影响。

金鸡纳生物碱衍生手性双胺配体的合成及其在不对称氢转移反应中的催化作用

以价廉易得的天然金鸡纳生物碱奎宁和辛可宁为原料,在温和条件下容易地合成了6种手性双胺配体. 考察了它们与过渡金属Ir和Rh形成的配合物在苯乙酮不对称氢转移反应中的催化活性和不对称诱导作用. 结果表明, 9-氨基金鸡纳生物碱配体具有良好的不对称催化活性,而当配体中的氨基被取代后其对映选择性降低. 将9-氨基（9-脱氧）表辛可宁的Ir配合物用于其它芳香酮的不对称氢转移反应时,该配体也显示了很高的催化活性（80%～90%收率）和对映选择性（除对氯苯乙酮ee值为72%外,其余芳香酮ee值均为95%～97%）.