脯氨酸衍生的胺基吡啶四氮锰配合物催化双氧水参与的烯烃不对称环氧化反应（英文）

自然界中存在许多的金属酶,它们参与促进各种各样的氧化反应,例如羟化反应,环氧化反应等.金属酶催化的反应具有催化效率高、反应条件温和、选择性高等优点.受大自然中的金属酶结构及其性质的启发,人们提出了仿生催化氧化的理念,并开始对金属酶进行模拟,致力于发展清洁氧化的反应方式.在过去的几十年中,科学家们设计合成了一系列仿生金属配合物催化剂.例如,利用非手性的乙二胺骨架设计合成出四齿氮配体MEP(N,N'-dimethylN,N'-bis(2-pyridinylmethyl)ethane-1,2-diamine),将其制备成相应的铁配合物催化剂,该铁催化剂可以很好的实现脂肪族烯烃的环氧化,产率高达90%.2003年,Stack小组首次报道了利用手性N,N-二甲基环己二胺骨架衍生的四齿氮配体金属配合物Mn-MCP-(OTf)2(MCP=N,N-dimethyl-N,N-bis(2-pyridylmethyl)cyclohexane-trans-1,2-diamine)催化的不对称环氧化反应.该反应的对映选择性仅仅为10%.因此,发展新型手性四氮配体金属配合物,用于高产率、高对映选择性的不对称环氧化反应,值得进行深入研究.近年来发展的一些含手性二胺骨架的四齿氮配体,例如PDP(2-[[2-(1-(pyridin-2-ylmethyl)-pyrrolidin-2-yl)pyrrolidin-1-yl]methyl]pyridine),被应用到不对称环氧化反应中,但是其手性二胺骨架为联吡咯,价格昂贵,难以制备.这在很大程度上限制了其在不对称合成中的实际应用.因此,利用一些易于合成的手性二胺骨架,发展结构新颖、催化性能优良的四氮金属配合物,成为实现高效、高选择性不对称环氧化反应的关键.在之前的工作基础上,本文以简单易得、价格低廉的天然氨基酸——L-脯氨酸为起始原料,选取吡啶环和含取代基的吡啶环作为侧基氮供体,制备了三种手性四齿氮配体.随后,我们利用新发展的手性四齿氮配体,合成了相应的锰配合物,并且分别将其运用于烯烃不对称环氧化反应中,仔细评估了这些锰金属配合物的催化性能.建立了以0.2 mol%的锰配合物为催化剂,0.5当量的2,2-二甲基丁酸为添加剂,30%双氧水为氧化剂,反应温度为–30 oC,乙腈为溶剂的催化不对称环氧化反应体系.反应结果显示:该催化剂催化的不对称环氧化反应底物适用性广泛,其中苯乙烯、苯并吡喃、烯酰胺等化合物均可以被成功地转化为相应的环氧化物,得到中等至优异的对映选择性(产率最高可达95%,对映选择性最高可达99%).     

非血红素铁、锰配合物催化烯烃不对称环氧化反应研究进展

手性环氧化物是重要的有机反应中间体.金属氧化酶催化的氧化反应通常具有高效、高选择性、反应条件温和和绿色的特点,模拟其中的非血红素铁加氧酶设计合成一系列手性四氮铁锰配合物催化烯烃不对称环氧化反应成为获得高产率、高对映选择性的手性环氧化物的一个重要方法.本文综述了近年来非血红素手性四氮铁锰配合物催化烯烃不对称环氧化反应的研究进展及相应的机理研究.     

非血红素N4配体Mn(III)配合物催化烯烃的不对称环氧化反应

利用Mn(OAc)3与手性四氮配体制备了非血红素N4配体的Mn(Ⅲ)配合物,并将其应用于催化α,β-不饱和烯酮和简单烯烃的不对称环氧化反应,考察了氧化剂H2O2的量和添加剂HOAc的量等条件对反应结果的影响,研究了该催化剂的底物适用范围,获得了51%~94%的ee值.     

氮杂冠醚取代非对称双Schiff碱配合物催化氧化对二甲苯研究

将一系列苯并-10-氮杂-15-冠-5或吗啉基取代的不对称双Schiff碱配合物作为催化剂,在常压和120℃条件下用于催化氧化对二甲苯研究。探讨了Schiff配合物中心金属离子、Schiff碱配体中挂接的氮杂冠醚环、配体芳环上取代基等对催化氧化对二甲苯反应活性及其氧化产物选择性的影响。实验结果表明:配合物中氮杂冠醚的存在能显著缩短反应诱导期、提高催化活性和选择性;Schiff碱Mn(Ⅲ)配合物比Schiff碱Co(Ⅱ)和Schiff碱Cu(Ⅱ)具有更高的催化活性;氮杂冠醚Schiff碱Mn(Ⅲ)配合物催化氧化二甲苯的转化率和产物选择性分别达75%和90%。     

双[N,N'-1,2-亚乙基-2,2'-(苯基亚甲基)二(3,4-二甲基吡咯-5-醛缩亚胺)]合双锰的合成、光谱特征及拟酶催化性能的研究

首次报道了一个新的拟酶模型物--双[N,N'-1,2-亚乙基-2,2'-(苯基亚甲基)二(3,4-二甲基吡咯-5-醛缩亚胺)]合双锰的合成方法及光谱特征;并对用PhIO单加氧化环己烷反应的催化性能及自氧化反应进行了研究.结果表明,此Schiff碱双锰配合物的催化性能及稳定性与金属卟啉TPPMnCl相似.     

轴向有机配体对Schiff碱配合物模拟酶催化性能的影响

研究了13种轴向有机中性配体(咪唑、嘧啶、吡唑、吡嗪、哌啶、4-甲基吡啶、3-甲基吡啶、2-甲基吡啶、2,6-二甲基吡啶、三苯基膦、噻吩、呋喃、吡咯)对Schiff碱双锰配合物在模拟酶催化PhIO单加氧化环己烷反应中催化性能的影响。结果表明,这些轴向有机配体均能提高Schiff碱金属配合物的催化活性;一般轴向配体碱性愈强,催化剂的催化活性愈高。     

双[N,N'-亚烃基-2,2'-(芳亚甲基)二(3,4-二甲基吡咯-5-醛缩亚胺)]合双锰(Ⅱ)的合成、光谱特征及拟酶催化性能研究

首次报道了新型Schif碱类配体双[N,N-亚烃基-2,2-(苯亚甲基)二(3,4-二甲基吡咯-5-醛缩亚胺)]和双[N,N-(1,2-亚乙基)-2,2-(4-甲氧基苯亚甲基)二(3,4-二甲基吡咯-5-醛缩亚胺)]及其双锰配合物的合成方法、光谱特征及用配合物催化PhIO单加氧化环己烷反应的研究。     

Synthesis and catalytic performance in olefim epoxidation of Mn ( Ⅲ ) complexes with N, N'-bis ( 2'-hydroxylacetophenone ) diamine

本文合成了N,N'-双(2'-羟基苯乙酮)缩乙二胺、N,N'-双(2'-羟基苯乙酮)缩1,2-丙二胺、N,N'-双(2'-羟基苯乙酮)缩1,3-丙二胺和N,N'-双(2'-羟基苯乙酮)缩邻苯二胺四种Schiff配体以及它们的锰(Ⅲ)配合物1,2,3和4.并考察了这四种锰(Ⅲ)配合物作为催化剂,催化以NaOCl为氧源环氧化苯乙烯和环己烯的反应的性能.同对考察了反应温度、助配体、NaOCl的浓度以及pH值对催化环氧化反应的影响.     

新型手性Salen配体及其与Ti,Ga配合物的合成

基于手性1,2-环己二胺Salen配体在不对称合成中具有极重要的地位,其与金属离子形成的手性配合物催化许多不对称反应,取得了好的结果.因此此类催化剂的合成及其应用研究一直是不对称合成中的一个热点.     

N,N’-双(2’-羟基苯乙酮)缩二胺合锰(Ⅲ)的合成和催化烯烃环氧化研究

本文合成了N,N’-双(2’-羟基苯乙酮)缩乙二胺、N,N’-双(2’-羟基苯乙酮)缩1,2-丙二胺、N,N’-双(2’-羟基苯乙酮)缩1,3-丙二胺和N,N’-双(2’-羟基苯乙酮)缩邻苯二胺四种Schiff配体以及它们的锰(Ⅲ)配合物1,2,3和4。并考察了这四种锰(Ⅲ)配合物作为催化剂,催化以NaOCl为氧源环氧化苯乙烯和环己烯的反应的性能。同时考察了反应温度、助配体、NaOCl的浓度以及pH值对催化环氧化反应的影响。     

Synthesis of analogs of amrinone: 4-(3,4-Disubstitutedphenyl)pyridines and derivatives thereof

4-(3,4-Dimethoxyphenyl)pyridine ( 5c ) prepared by the coupling of 3,4-dimethoxyphenyldiazonium chloride with pyridine was converted to 4-(4-pyridinyl)benzene-1,2-diol ( 6c ) by treating with hydrobromic acid. Diazotization of 4-(4-pyridinyl)benzeneamine ( 7 ) and 3-(4-pyridinyl)benzeneamine ( 12 ) gave the corresponding phenols 8 and 13 which were nitrated to give 2-nitro-4-(4-pyridinyl)phenol ( 9 ) and 2-nitro-5-(4-pyridinyl)-phenol ( 14 ), respectively. Reduction of these nitrophenols gave the corresponding aminophenols 10 and 16 which in turn were reacted with N,N'-carbonyldiimidazole to yield benzoxazolones 11 and 17 , respectively. Catalytic reduction of 2-nitro-4-(4-pyridinyl)benzeneamine ( 18 ) gave 4-(4-pyridinyl)benzene-1,2-diamine ( 19 ) which was reacted with orthoesters, urea, tetraethoxymethane, and N,N'-di(carbomethoxy)methylpseudothiourea to give the corresponding benzimidazole derivatives 20, 21, 22 , and 23 .     

Novel synthesis of pyrido[1,2-a]benzimidazoles via reaction of N-acyl arylhydroxylamines with pyridine

The reduction of 4-chloro-3,5-dinitrobenzonitrile via catalytic hydrogenation and/or titanium trichloride produced three successive hydroxylamines 6,7 , and 8 that were fully characterized during complete reduction to the diamine 9. The nitrohydroxylamine 6 was acetylated to the mono-N-acetyl and bis-acetyl derivatives 10 and 11 which reacted with pyridine to afford the pyrido[1,2-a]benzimidazole 13 . An analoguous series of reactions was executed with 4-chloro-3,5-dinitrobenzotrifluoride to afford the pyrido[1,2-a]benzimidazole 21 . Structure confirmation of 21 was established via an x-ray determination. The mechanism of the transformation is discussed.     

Solid state N and C NMR study of dioxomolybdenum (VI) complexes of Schiff bases derived from trans-1,2-cyclohexanediamine

The ¹³C, ¹⁵N CP MAS NMR and FT-IR spectra of dioxomolybdenum (VI) complexes of trans-N,N′-bis-(R-salicylidene)-1,2-cyclohexanediamine (R=H, R=3,5-diCl, R=3,5-diBr, R=4,6-diOCH₃), trans-N,N′-bis-(2-OH-naphthylidene)-1,2-cyclohexanediamine and trans-N-(salicylidene)-N′-(2-OH-naphthylidene)-1,2-cyclohexanediamine have been measured. Comparative analysis of the NMR and IR spectra of the complexes with those of the corresponding ligands has shown that the complexation of the di-Schiff bases leads to changes in the conformation of the ligands and the charge redistribution. The asymmetric structure and non-planar structure of the complexes have been suggested.     

Steric modifications tune the regioselectivity of the alkane oxidation catalyzed by non-heme iron complexes

Iron complexes with the tetradentate N-donor ligand N,N'-di(phenylmethyl)-N,N'-bis(2-pyridinylmethyl)-1,2-cyclohexanediamine (bbpc) are reported. Despite the benzyl groups present on the amines, the iron compounds catalyze the oxygenation of cyclohexane to an extent similar to those employing less sterically encumbered ligands. The catalytic activity is strongly dependent on the counterion, with the highest activity and the strongest preference for alkane hydroxylation correlating to the most weakly coordinating anion, SbF(6)(-). The selectivity for the alcohol product over the ketone is amplified when acetic acid is present as an additive. When hydrocarbon substrates with both secondary and tertiary carbons are oxidized by H(2)O(2), the catalyst directs oxidation toward the secondary carbons to a greater degree than other previously reported iron-containing homogeneous catalysts.     

Synthesis, structure, and magnetic behavior of a series of trinuclear Schiff base complexes of 5f (UIV, ThIV) and 3d (CuII, ZnII) ions

The reaction of [M(H(2)L(i))] (M = Cu, Zn) and U(acac)(4) in refluxing pyridine produced the trinuclear complexes [[ML(i)(py)(x)](2)U] [L(i) = N,N'-bis(3-hydroxysalicylidene)-R, R = 1,2-ethanediamine (i = 1), 2-methyl-1,2-propanediamine (i = 2), 1,2-cyclohexanediamine (i = 3), 1,2-phenylenediamine (i = 4), 4,5-dimethyl-1,2-phenylenediamine (i = 5), 1,3-propanediamine (i = 6), 2,2-dimethyl-1,3-propanediamine (i = 7), 2-amino-benzylamine (i = 8), or 1,4-butanediamine (i = 9); x = 0 or 1]. The crystal structures show that the central U(IV) ion adopts the same dodecahedral configuration in all of these compounds, while the Cu(II) ion coordination geometry and the Cu...U distance vary with the length of the diimino chain of the Schiff base ligand L(i). These geometrical parameters have a major influence on the magnetic properties of the complexes. For the smallest Cu...U distances (i = 1-5), the Cu-U coupling is antiferromagnetic and weak antiferromagnetic interactions are present between the Cu(II) ions, while for the largest Cu...U distances (i = 6-9), the Cu-U coupling is ferromagnetic and no interaction is observed between the Cu(II) ions. The magnetic behavior of the [[CuL(i)](2)Th] compounds (i = 1, 2), in which the Th(IV) ion is diamagnetic, confirms the presence of weak intramolecular antiferromagnetic coupling between the Cu(II) ions.     

Preparation,characterization, DFT calculations and ethylene oligomerization studies of iron(II) complexes bearing 2-(1H-benzimidazol-2-yl)-phenol derivatives

Five 2-(1H-benzimidazol-2-yl)-phenol derivatives including 1H (HL₁), 5-chloro-(HL₂), 5-methyl-(HL₃), 5,6-dichloro-(HL₄), and 5,6-dimethyl-(HL₅) were synthesized by the reaction of their corresponding benzene-1,2-diamine precursors and 2-hydroxybenzaldehyde which subsequently was employed in complexation with Fe(II) to prepare complexes C1–C5, respectively. Indeed, in all complexes, the ligands were coordinated as bidentate, via the C=N nitrogen and hydroxy oxygen atom of benzimidazole moiety and phenol ring, respectively. The compounds were characterized by FTIR, UV–vis, ¹H- and ¹³C-NMR spectropscopy, ICP, and elemental analysis (C, H, and N). The purity of these compounds was determined by melting point (m.p )and TLC. The synthesized ligands and complexes were geometrically optimized by Gaussian09 software at B3LYP/TZVP level of theory and satisfactory theoretical–experimental agreement was achieved for analysis of IR data of the compounds. Catalytic behavior of the iron(II) complexes was investigated for ethylene reactivity. On activation with diethylaluminum chloride (Et₂AlCl), iron(II) complex (C4) showed the highest activity (1686 kg oligomers.mol^?1(Fe).h^?1) for ethylene oligomerization when it contains chlorine substituents and exhibits good selectivity for linear 1-butene. The steric and electronic effects of ligands were investigated in detail on the influence of their catalytic activities.     

Asymmetric structure of cis‐[N‐(9‐anthracenylmethyl)‐1,2‐ethanediamine]dipyridineplatinum(II) dinitrate

Platinum antitumour agents, containing aromatic rings, which are used for targeting DNA in effective therapies for the treatment of cancer. We have synthesized the title metallocomplex with an aromatic ligand and determined its crystal structure. In many cases, complexes of platinum and other metals have a symmetrical structure. In contrast, the platinum(II) complex with pyridine and N‐(9‐anthracenylmethyl)‐1,2‐ethanediamine as ligands (systematic name: cis‐{N‐[(anthracen‐9‐yl)methyl]ethane‐1,2‐diamine‐κ²N ,N ′}bis(pyridine‐κN )platinum(II) dinitrate), [Pt(C₅H₅N)₂(C₁₇H₁₈N₂)](NO₃)₂, is asymmetric. Of the two pyridine ligands, only one is π‐stacked with anthracene, resulting in an asymmetric structure. Moreover, the angle of orientation of each pyridine ligand is variable. Further examination of the packing motif confirms an intermolecular edge‐to‐face interaction.     

Bis(oxazoline) Lewis acid catalyzed aldol reactions of pyridine N-oxide aldehydes--synthesis of optically active 2-(1-hydroxyalkyl)pyridine derivatives: development, scope, and total synthesis of an indolizine alkaloid

A new, short, and simplified procedure for the synthesis of optically active pyridine derivatives from pro-chiral pyridine-N-oxides is presented. The catalytic and asymmetric Mukaiyama aldol reaction between ketene silyl acetals and 1-oxypyridine-2-carbaldehyde derivatives catalyzed by chiral copper(II)-bis(oxazoline) complexes gave optically active 2-(hydroxyalkyl)- and 2-(anti-1,2-dihydroxyalkyl)pyridine derivatives in good yields and diastereoselectivities, and in excellent enantioselectivities-up to 99 % enantiomeric excess. As a synthetic application of the developed method, a full account for the asymmetric total synthesis of a nonnatural indolizine alkaloid is provided.     

Application of chiral N,N′-dialkyl-1,2-cyclohexanediamine derivatives in asymmetric copper(II)-catalyzed Henry reactions

A series of chiral N,N′-dialkyl-1,2-cyclohexanediamine derivatives were designed, synthesized, and applied as ligands in asymmetric copper(II)-catalyzed Henry reactions. The catalysts based on such ligands and copper(II) acetate were found to promote asymmetric Henry reactions between aromatic/aliphatic aldehydes and nitromethane efficiently, and could provide the corresponding β-nitroalcohols in very good yields and with enantioselectivities of up to 93.6%.     

双（呋喃甲醛）缩二胺钴（II）配合物的合成及其氧合和催化氧化性能研究

合成和表征了氯化双（呋喃甲醛）缩邻苯二胺合钴（II）（1）、氯化双（呋 喃甲醛）缩乙二胺合钴（II）（2）、氯化双（呋喃甲醛）缩1,2-丙二胺合钴（ II）（3）和氯化双（呋喃甲醛）缩1,3-丙二胺合钴（II）（4）。在吡啶溶液中 和不同温度下,测定了配合物的饱和吸氧量,求出了氧加合常数和热力学参数ΔH °,ΔS°。并以这些配合物为催化剂,活化分子氧氧化环已烯得到高选择性的烯 丙位氧化产物。讨论了温度、配体结构对配合物氧合性能的影响和配体结构以及添 加NHPI（N-羟基邻苯二甲酰亚胺）对环已烯氧化反应的影响。