烯酮亚胺盐化学的研究进展

烯酮亚胺盐是一类独特的杂联烯,高亲电性以及累积二烯的结构特点赋予了烯酮亚胺盐反应的多样性.介绍了非金属亲电试剂活化酰胺或炔酰胺制备的烯酮亚胺盐.该类烯酮亚胺盐与不同种类的亲核试剂主要发生亲电加成反应、亲电取代反应、环加成反应.近年来,烯酮亚胺盐参与的亲电重排反应得到较大发展,所以将对这一进展作重点介绍.     

烯酮中间体及其在不对称环加成反应中的应用

烯酮作为一种重要的中间体在有机合成中具有非常广泛的应用,本文主要对烯酮中间体的结构与制备及近年来烯酮与醛或亚胺的[2+2]环加成反应以及与活泼不饱和双键的[2+2]或[4+2]环加成反应在不对称有机合成中的应用进展作一综述,包括不同催化剂对反应的立体选择性控制及其反应机理。     

氮杂环卡宾催化烯酮与N-酰基偶氮化合物的[4＋2]环加成反应

烯酮的不对称环加成反应是合成手性杂环化合物的高效方法．近来,中国科学院化学研究所叶松等发展了手性氮杂环卡宾（NHC）催化的烯酮的不对称环加成反应新方法,实现了烯酮分别与亚胺、醛及仅肛不饱和酮反应,     

α-乙酰基二硫缩烯酮Vilsmeier反应在共轭三烯化合物合成中的应用

以α-乙酰基二硫缩烯酮为起始原料,通过与Vilsmeier试剂反应得到亚胺盐正离子中间体,利用亚胺盐正离子中间体与碳亲核体反应,成功制备了多取代共轭三烯类化合物.该方法具有原料易得、反应条件温和及实验步骤简单等优点.该反应不仅建立了一种简单、有效合成多取代共轭三烯化合物新方法,而且扩展了α-乙酰基二硫缩烯酮类化合物在有机合成中的进一步应用.     

镍(Ⅱ)催化烯酮亚胺的不对称共轭加成反应:高对映选择性构建连续两个全碳季碳中心

正Angew.Chem.Int.Ed.2017,56,13107~13111烯酮亚胺(Silyl ketene imines,SKIs)是一类含有累积多烯结构的化合物,它可以被用来合成含有季碳中心的腈类化合物.目前烯酮亚胺参与的不对称Acylation、Aldol、Mannich、Protonation等反应取得了优秀的结果.然而,由于区域选择性和立体选择性问题,烯酮亚胺参与的不对称共轭加成反应仍存在着挑战.同时,该反应可以一步高效地构建连续两个全碳季碳中心.基于此,四川大学化学学院冯小明课题组使用手性双氮氧配体/镍(II)配合物为催化剂,     

磺酰叠氮和炔参与的多组分反应研究进展

磺酰叠氮和炔参与的铜催化多组分反应成为近年来有机化学研究的热点.磺酰叠氮和炔在铜催化下生成的N-磺酰基烯酮亚胺中间体,可以被胺、醇和水等各类亲核试剂捕捉,也可以和各种类型的烯烃发生[2+2]、[3+2]和[4+2]等环加成反应.N-磺酰基烯酮亚胺中间体受到来自双官能团底物的分子内基团进攻以及随后发生的(环)重排和σ键迁移,更是成为构建结构丰富的具有生理和药物活性(杂)环类化合物的重要手段.主要对该领域近年来的最新研究成果进行了综述.     

碳二亚胺的化学

碳二亚胺(carbodiimide)是含有-N=c=N-结构的一类化合物,它们与双烯C=C=C,烯酮C=C=O,异氰酸酯-N=C=O等类似,都是含有聚积态双键的不饱和化合物。早在九十多年前,第一个碳二亚胺衍生物——双苯基碳二亚胺就问世了。由于它具有特殊的结构,所以,这一类化合物表现得特别活泼,能与多种含活泼氫的化合物:如水、羧酸、氨、卤化氫、醇、酚等发生加成反应。可是,在较长的年代里,人们的研究工作,都偏重在性质和合成方面;直到1955年应用碳二亚胺作     

亮点介绍

正铜催化甲亚胺叶立德与β-三氟甲基β,β-双取代烯酮不对称环加成反应Angew.Chem.Int.Ed.2016,55,6324~6328多取代的手性吡咯烷类化合物广泛分布于天然产物及具有生理活性的药物中.通过甲亚胺叶立德与缺电子烯烃的不对称环加成制备手性吡咯烷类化合物是最有效和简单的方法之一.目前,对于简单的缺电子烯烃(如单取代、双取代烯烃)已经有了大量的报道,但是对于立体位阻较大、反应活性较低的β,β-二取代缺电子烯烃还没有实现其不对     

喹唑啉-4-酮衍生物的合成及抗肿瘤活性

以邻氨基苯甲酸、芳醛和甘氨酸乙酯为原料,利用亚胺和亚胺烯酮的加成反应,芳构化合成了系列含氨基酸链的C-2和N-3双取代的喹唑啉-4-酮衍生物5.酸性条件下脱除羧甲基,设计合成了连有氨基侧链的喹唑啉酮衍生物9,并评价了化合物的抗肿瘤细胞增殖活性.化合物9ba和9bc具有较好的抗Hela细胞增殖活性,IC_(50)值分别为8.16和7.47μmol/L,而9bc和9bd具有较好的抗A549细胞增殖活性,IC_(50)值分别为5.62和9.54μmol/L.构效关系表明,C-2位香豆素(较大的π平面芳环)取代以及氨基侧链的引入有利于化合物的抗肿瘤活性.     

基于N,S-缩烯酮的杂环合成的研究

N,S-缩烯酮是一类重要的有机合成中间体,其官能团的多样性决定了反应的多样性。N,S-缩烯酮的主要反应有与亲核体的共轭加成、与金属有机试剂的选择性加成、环合（五元环或六元环）、还原和缩合等反应,其在杂环合成中具有非常重要的意义。本文主要综述了N,S-缩烯酮的制备及其在参与合成含氮杂环（吡咯、吲哚、吡啶、嘧啶等）、含氧杂环（呋喃、吡喃等）及在多组分反应中的应用,重点介绍了各类反应的普适性、反应机理或衍生化的研究结果,以更好地认识N,S-缩烯酮分子,并期望通过N,S-缩烯酮实现选择性的合成各类所需的杂环化合物,以促进N,S-缩烯酮在杂环合成中的应用。此外,N,S-缩烯酮合成的杂环化合物大部分具有潜在的生物活性,这将促进其在药物化学及药物合成领域的应用和发展。     

Cyclopropanone equivalents. Formation of 1-pyrrolizidione by a dicyclopropyl imine rearrangement.

A dicyclopropyl ketimine may be formed by the addition of cyclopropyllithium to 1-cyano-1-piperidinocyclopropane. Rearrangement of the ketimine takes place under acid catalysis to form 1-pyrrolizidinone.     

Asymmetric syntheses of α-amino acids via double chiral induction in alkylation of the ketimine derived from 2-hydroxypinan-3-one and menthyl glycinate

Asymmetric syntheses of (S)-α-amino acids in 28--98% optical yields via doublechiral induction in alkylations of ketimine 1 derived from (+)-2-hydroxypinan-3-one and (-)-men-thyl glycinate which is a chiral match pair have been studied. The factors controlling the diastereoselec-tivities in alkylation reactions of the ketimine, the properties of alkylating agents and various alkylationconditions are examined.     

2‐Hydroxybenzophenone as a Chemical Auxiliary for the Activation of Ketiminoesters for Highly Enantioselective Addition to Nitroalkenes under Bifunctional Catalysis

An organocatalytic system is presented for the Michael addition of monoactivated glycine ketimine ylides with a bifunctional catalyst. The ketimine bears an ortho hydroxy group, which increases the acidity of the methylene hydrogen atoms and enhances the reactivity, thus allowing the synthesis of a large variety of α,γ‐diamino acid derivatives with excellent stereoselectivity.     

Imide-aryl ether ketone block copolymers

Imide-aryl ether ketone block copolymers were prepared and their morphology and thermal and mechanical properties investigated. Two aryl ether ketone blocks were incorporated; the first was an amorphous block derived from bisphenol–A and the second block was a semi-crystalline poly(aryl ether ether ketone) prepared from a soluble and amorphous ketimine precursor. Bis(amino) aryl ether ketone and aryl ether ketimine oligomers were prepared via a nucleophilic aromaic substitution reaction with molecular weights ranging from 6,000 to 12,000 g/mol. The oligomers were co-reacted with 4,4′-oxydianiline (ODA) and pyromellitic dianhydride (PMDA) diethyl ester diacyl chloride in N-methyl–2-pyrrolidone (NMP) in the presence of N-methylmorpholine. The copolymer compositions, determined by H-NMR, of the resulting amic ester based copolymers ranged from 8 to 50 wt % aryl ether ketone or ketimine content. Prior to imide formation, the ketimine moiety of the aryl ether ketimine block was hydrolyzed (p-toluene sulfonic acid) to the ketone form producing the aryl ether ether ketone block. Compositions of this block were maintained low to retain solubility. Solutions of the copolymers were cast and cured to effect imidization, producing clear films with high moduli (ca. 2200 MPa) and elongations (33–100%). The copolymers displayed good thermal stability with decomposition temperatures in excess of 450°C. Multiphase morphologies were observed irrespective of the co-block type, block length or composition. © 1992 John Wiley & Sons, Inc.     

Highly enantioselective Rh-catalyzed transfer hydrogenation of N-sulfonyl ketimines

Several imine species comprising N-sulfinyl and N-sulfonyl ketimine, oxime, and enamine derivatives were subjected to asymmetric transfer hydrogenation in an azeotropic mixture of formic acid/triethylamine. Among them, the Rh-catalyzed transfer hydrogenation of N-sulfonyl ketimine afforded the corresponding 1-arylalkylamines in excellent yield and with high enantioselectivity.     

Electron ionization mass spectra and tautomerism of substituted 2‐phenacylquinolines

Tautomerism has been studied conventionally in solutions or in the solid state. However, the importance of mass spectrometry in the gas phase was realized relatively late. 2‐Phenacylquinolines are known to undergo ketimine‐enaminone tautomerism. The ratio of tautomers is dependent on the nature of the phenyl ring substituent and the Hammett substituent constants σ. Theoretical calculations indicate the presence of ketimine and enaminone tautomers in the gas phase. The electron ionization mass spectra of eight 2‐phenacylquinolines (ketimine form) were recorded at 70 eV in order to determine the fragmentation routes and to screen for the presence of their enaminone tautomers, (Z)‐2‐benzoylmethylene‐1,2‐dihydroquinolines, in the gas phase. The relative abundances or total ion currents of some ions correlated with the Hammett substituent constants and Hammett‐Brown constants. The product ions [M–CO]^{+ .} and [M–HCO]⁺ were observed. A reaction mechanism is suggested for the formation of these ions, requiring skeletal rearrangements. The results furnish information relating to tautomerism in the gas phase. Copyright © 2009 John Wiley & Sons, Ltd.     

Guanidine–Amide-Catalyzed Aza-Henry Reaction of Isatin-Derived Ketimines: Origin of Selectivity and New Catalyst Design

Density functional theory (DFT) calculations were performed to investigate the mechanism and the enantioselectivity of the aza-Henry reaction of isatin-derived ketimine catalyzed by chiral guanidine–amide catalysts at the M06-2X-D3/6-311+G(d,p)//M06-2X-D3/6-31G(d,p) (toluene, SMD) theoretical level. The catalytic reaction occurred via a three-step mechanism: (i) the deprotonation of nitromethane by a chiral guanidine–amide catalyst; (ii) formation of C–C bonds; (iii) H-transfer from guanidine to ketimine, accompanied with the regeneration of the catalyst. A dual activation model was proposed, in which the protonated guanidine activated the nitronate, and the amide moiety simultaneously interacted with the ketimine substrate by intermolecular hydrogen bonding. The repulsion of CPh₃ group in guanidine as well as N-Boc group in ketimine raised the Pauli repulsion energy (∆E_Pauli) and the strain energy (∆E_strain) of reacting species in the unfavorable si-face pathway, contributing to a high level of stereoselectivity. A new catalyst with cyclopropenimine and 1,2-diphenylethylcarbamoyl as well as sulfonamide substituent was designed. The strong basicity of cyclopropenimine moiety accelerated the activation of CH₃NO₂ by decreasing the energy barrier in the deprotonation step. The repulsion between the N-Boc group in ketimine and cyclohexyl group as well as chiral backbone in the new catalyst raised the energy barrier in C–C bond formation along the si-face attack pathway, leading to the formation of R-configuration product. A possible synthetic route for the new catalyst is also suggested.     

New synthesis of pyrazole and isoxazole derivatives

A convenient synthesis of 5-aryl-1-phenylpyrazoles and 5-arylisoxazoles, from readily available ketimine 1 dimethylformamide dimethylacetal and phenylhydrazine or hydroxylamine, is described.     

Selective Complexation of Hydrazone Based Ketimine with 3d, 4d,and 5d Metals: Synthesis,Characterization, and Biological Activity

Russian Journal of General Chemistry - The hydrazone derived ketimine of dehydroacetic acid and its metal {Cu(II), Ni(II), Zn(II), Fe(III), Cd(II), Pd(II), La(III), Nd(III), Ce(III)} complexes are...     

Direct transformation of secondary amides into secondary amines: triflic anhydride activated reductive alkylation

Versatile and mild: The first general method for the title transformation has been developed (see scheme; 2-F-Py=2-fluoropyridine; Tf=trifluorosulfonyl). The amines are synthesized in good yields and the ketimine intermediates can be isolated before the reduction. This method should find applications in the synthesis of nitrogen-containing bioactive molecules and medicinal agents.