Reactions of quadricyclane with fluorinated nitrogen-containing compounds. Synthesis of 3-aza-4-perfluoroalkyl-tricyclo[4.2.1.0]non-3,7-dienes

The cycloaddition reactions of quadricyclane (1) and polyfluorinated imines and nitriles were studied. Both (CF₃)₂CNH and (CF₃)₂CN(2-FC₆H₄) were found to have low reactivity towards 1, giving the corresponding [2 + 2 + 2] cycloadducts in a low yield. C₂F₅NCFCF₃ however, reacts with 1 rapidly, giving a mixture of two isomeric cycloadducts in a high yield. Perfluoroalkyl nitriles R_fCN (R_f = CF₃, C₂F₅, n-C₃F₇) were found to have surprisingly high reactivity to 1 producing exo-3-aza-4-(fluoroalkyl)-tricyclo[4.2.1.0^2,5]non-3,7-dienes in 56-81% yields at elevated temperature. Exo-3-aza-4-(perfluoroalkyl)-tricyclo[4.2.1.0^2,5]non-3,7-dienes rapidly react with CF₃Si(CH₃)₃ in the presence of CsF catalyst. The reaction results in addition of CF₃Si(CH₃)₃ across the CN bond of the azadienes with selective formation of only one stereoisomer of exo-3-aza-3-(trimethylsilyl)-4,4-bis(perfluoroalkyl)-tricyclo[4.2.1.0^2,5]non-7-enes. Silyl group in this compounds can be removed either by the action of tetrabutylammonium fluoride hydrate, leading to the formation of the corresponding amine after hydrolysis, or by reaction with HCl resulting in the formation of the corresponding amine hydrochloride.     

Rhodium-catalyzed and sonication-accelerated addition of aryltin and aryllead reagents to imines in air and water

In the presence of a rhodium catalyst, imines (1a-k) react with phenyltrimethyltin 2a or phenyltrimethyllead 2b in water and air under ultrasonic irradiation at 35 °C to give the corresponding diarylmethylamines (3a-k) in good yields.     

Study on Unexpected Cycloaddition Reactions of Imines with THF

Thesynthesisofnitrogen-containingheterocylesthroughcycloadditionreactionofimineshasstimulatedmuchpreparativeandmechanisticwork'".Whenweattemptedtosynthesizeapolycycliccompound3byadditionreactionofimineland5-norbornene-2,3-dicarboxylicacid2,however,unexpectedtricycliccompounds4and6wereobtainedinsteadofthedesignedproduct3(Schemcl).Heretetrahydrofuran(THF)servedasthesourceofdihydrofiJranwhichunderwentcycloadditionwithlgiving4and6.Ananalogousreactionwasnotedpreviouslyinthislaboratory'(Scheme2).…     

Progress of 3-aminopyridine-based amide,urea, imine and azo derivatives in supramolecular gelation

Supramolecular gels derived from low molecular weight gelators are considered to be fascinating soft and smart materials. Gelators of this class form gel networks involving noncovalent interactions and show various applications in many areas. The structural softness and the arrangement of the gelator molecules in the aggregated state have the collaborative effect to intensify the properties of the molecules for their potential applications in material chemistry. Of the various properties, stimulus responsibility is a desired property of supramolecular gel that finds profound application in sensing. In this review, a comprehensive summary of the work on 3-aminopyridine-based amide, urea, imine and azo gelators of different architectures indicating their different uses in supramolecular chemistry has been focused.     

温和条件下钒催化氧化胺、醇和胺直接合成亚胺(英文)

开发了钒催化氧化胺、醇和胺直接合成亚胺催化体系,无须额外的添加剂或促进剂,空气作为环境友好的氧源,温和条件下,能高收率地得到各种对称和非对称亚胺,并且催化剂非常容易制备和使用.该催化体系对含杂原子亚胺的合成也非常有效.     

纳米二氧化铈催化制备亚胺

近年来,金属氧化物的晶面效应及其独特的催化性能引起研究者的广泛关注.其中,二氧化铈(CeO2)因具有储放氧性质、易于形成氧空位等特点,在诸多领域得到应用,尤其是作为催化剂,可用作活性相、载体、复合催化材料等. CeO2的晶面效应主要由于晶面上氧空位的性质引起的.目前,这方面的研究主要集中在高温条件下氧空位的动态转化过程,如水汽变换反应、有机物脱除等.但是高温下CeO2中氧空位的活泼性,增加了晶面效应的复杂性.因此,利用低温液相有机反应作为探针,研究晶面效应是一种可靠的解决方案.我们近些年的工作研究了CeO2不同晶面上的酸性及催化水解性能,在本研究中,我们提出在温和条件下, 采用有机探针反应,研究不同晶面的氧化还原性质.亚胺类化合物作为一类重要的含氮有机中间体,在生物、农药、医药等领域中具有重要应用.传统的亚胺合成方法是将醛类化合物或酮类化合物与胺类在酸催化剂的作用下直接缩合.近年来出现了新的亚胺合成方法,例如通过胺类氧化脱氢、炔烃的氢胺化、醇胺脱氢/氧化偶联等,其中醇胺脱氢/氧化偶联的方法因具有原料廉价易得、过程清洁等优点,而成为研究热点.最近, Masazumi Tamura等研究发现CeO2能够在温和条件下高效催化醇胺氧化偶联制亚胺,通过一系列表征发现CeO2的高活性主要由于其氧空位中存在丰富的活性氧物种.然而, CeO2的晶面效应及其在此反应中的催化性能,以及不同晶面上的氧化还原性质还有待进一步的研究.本文研究了CeO2的晶面效应及其在醇胺氧化偶联制亚胺反应中的催化性能.在温和的反应条件下(60 oC), CeO2能够高效催化苯甲醇与苯胺反应制备亚胺,并且对底物具有很好的普适性,在催化一系列醇与胺氧化偶联制亚胺的反应中,对于大部分底物,醇类化合物的转化率可达89%以上,亚胺类化合物的选择性可达90%以上.通过水热合成法分别制备了棒状CeO2、立方体CeO2和八面体CeO2,并通过X射线衍射、透射电子显微镜和高分辨透射电子显微镜确证了其结构和形貌,结果表明三种形貌的CeO2均为纯相的CeO2,其中棒状CeO2暴露(110)和(100)晶面,立方体CeO2暴露(100)晶面,八面体CeO2暴露(111)晶面.并以苯甲醇氧化反应和苯甲醇与苯胺反应为探针研究了其催化性能.结果发现：不同形貌的CeO2具有显著不同的催化活性,其中棒状CeO2表现出最优异的催化性能,立方体CeO2和八面体CeO2次之.通过Raman光谱表征了不同形貌CeO2的氧空位性质并比较了它们的氧空位浓度.结果发现：棒状CeO2的氧空位浓度相对值(A595/A462)为0.077,高于立方体CeO2和八面体CeO2.通过比较分析计算可知,在CeO2(110),(100)和(111)三种晶面中,(110)晶面因其具有最多的氧空位而表现出最高的催化活性和优异的氧化还原性质,(110)晶面上亚胺的生成速率为4.618 mmol/(g·h),分别为(100)晶面和(111)晶面上的32倍和49倍.该研究有助于提高认识CeO2基催化材料的低温氧化还原性质.     

Modular Synthesis of Multisubstituted Furans through Palladium‐Catalyzed Three‐Component Condensation of Alkynylbenziodoxoles,Carboxylic Acids,and Imines

Mild and regiocontrolled synthesis of a multisubstituted furan is achieved through Pd(OAc)₂‐catalyzed room‐temperature condensation of an alkynylbenziodoxole, a carboxylic acid, and an enolizable ketimine, which contribute to C1, CO, and C2 fragments, respectively, to the furan skeleton. The reaction tolerates a broad range of functional groups in each of the reaction components, and enables highly modular and flexible synthesis of variously substituted furans. The reaction is particularly effective for the rapid generation of tri‐ and tetraarylfurans and furan‐containing oligoarylenes without relying on conventional cross‐coupling chemistry.     

N‐Heterocyclic‐Carbene‐Catalyzed Umpolung of Imines

N‐Heterocyclic carbene (NHC) catalysis has been widely used for the umpolung of aldehydes, and recently for the umpolung of Michael acceptors. Described herein is the umpolung of aldimines catalyzed by NHCs, and the reaction likely proceeds via aza‐Breslow intermediates. The NHC‐catalyzed intramolecular cyclization of aldimines bearing a Michael acceptor resulted in the formation of biologically important 2‐(hetero)aryl indole 3‐acetic‐acid derivatives in moderate to good yields. The carbene generated from the bicyclic triazolium salt was found to be efficient for this transformation.     

About the different reactivity of dinuclear palladium and platinum compounds with trispyrrolylphosphine: Synthesis and X-ray crystallographic results of new palladium complexes containing P-pyrrolyl bonds

The reaction of [Pt(μ-Cl)(κ,η²-COE-MeO)]₂ (2) (COE-MeO = 2-methoxy-5-cycloocten-1-yl) with trispyrrolylphosphine yields [PtCl{P(pyrl)₃}(κ,η²-COE-MeO)] (3), in contrast to the crown-cycle complex [Pd(μ-Cl) {P(pyrl)₃}]₈ (1) obtained with the analogous palladium complex. The different reactivity has been explained in terms of the higher lability of the carbon-carbon double bond in the starting palladium compound, as compared with the related platinum derivative. The reaction of 1 with the ligand 2-[(pyridin-2-ylmethylene)aminophenol], (HNN′O), in the presence of thalium salt and NEt₃, yields the complex [Pd(κ³N,N′,O-py-CHN-C₆H₄O)(P(O)(pyrl)₂)] (5), which contains, for the first time, a di(N-pyrrolyl)phosphonato-P ligand. Treatment of [PdCl(κ³N,N′,O-py-CHN-C₆H₄O)] with P(pyrl)₃ gives the amido derivative [PdCl{κ³P,N,N-(P(pyrl)₂-O-C₆H₄-N-CH(CH₂-CO-CH₃)-py)}] (7), which displays a N-Pd-P-O-C₂ six-membered metallacycle. In addition, the latter compound has been able to insert an acetone molecule into its framework. The crystal structures of 5 and 7 were solved by X-ray diffraction analysis.