氮杂环丙烷[3+2]环加成反应研究进展

介绍了最近几年在不同催化体系下,氮杂环丙烷与含双键化合物的[3+2]环加成反应研究进展。     

氮杂环丙烷与双键化合物的[3+2]环加成反应研究进展

咪唑烷、恶唑烷和吡咯烷等五元氮杂环在有机合成的应用十分广泛,而氮杂环丙烷与不饱和双键化合物的[3+2]环加成反应是合成此类化合物的一种便捷高效的方法。综述了近年来氮杂环丙烷与亚胺、烯烃、醛酮等含有双键化合物的[3+2]环加成反应研究进展,并对其发展方向进行了展望。     

氰基富勒烯[60]和1,2-二氰基富勒烯[60]的合成和表征

亲核加成是Fullerene[60]典型、特征的反应,由于富勒烯分子有很多反应活性点,大多数亲核取代发生多元加成,生成难分离的混合物。Fullerene[60]和氰化钠的加成反应证明:以N,N-二甲基甲酰胺和邻二氯苯为混合溶剂,氰基负离子(CN-)与C60能发生可控的一元亲核加成反应,生成[C60(CN)]-,不分离此中间体,直接加入三氟乙酸得到产物C60(CN)H;如果在C60(CN)-的溶液中加入对甲苯磺酰氰,可高收率地得到C60(CN)2。利用1H NMR、质谱、元素分析对产物的组成和结构进行了确认和鉴定。     

苯甲酸催化的三组分[3+2]环加成反应合成六氢吡咯并[2,1-a]异喹啉化合物

发展了一种合成六氢吡咯并[2,1-a]异喹啉化合物的新方案,以苯甲酸为催化剂,4?分子筛为添加剂,催化芳香醛、1,2,3,4-四氢异喹啉和N-取代马来酰亚胺经串联的醛胺缩合和[3+2]环加成反应,合成了一系列六氢吡咯并[2,1-a]异喹啉化合物.主要考察了催化剂、溶剂、反应时间及反应温度对产物产率的影响,最终确定在60...     

富勒烯[60]有机高分子化合物非线性光学的研究进展

介绍了近几年来富勒烯 [60]有机高分子化合物在非线性光学领域的研究进展以及对它们的合成方法进行了综述。     

氮杂环丙烷与腈的[3+2]环加成反应生成咪唑啉的研究进展

咪唑啉是一种非常重要的药物中间体,其通过氮杂环丙烷与腈的[3+2]环加成反应是非常有效合成方法.综述了这种方法的研究进展,并且进行了评价与展望.     

[60]富勒烯三元环化反应及其衍生物功能研究

对[60]富勒烯的三元环化反应及其衍生物的功能研究进行了概述,讨论了[60]富勒烯的三元环化反应的发生机理.重点阐述了[60]富勒烯三元环化典型反应及获得的富勒烯衍生物的生物医药功能等,对今后的工作进行了展望.     

富勒烯[60]-曲酸衍生物的合成

富勒烯[60]是由相邻的六元环和五元环组合而成的中空状球形分子,环中含有30个双键,具有缺电子烯烃性质,易发生加成反应。文章通过对甲苯磺酰肼与曲酸缩合反应生成曲酸对甲苯磺酰腙,再与富勒烯[60]发生环加成反应合成了富勒烯[60]-曲酸衍生物,产率32%。目标产物的结构经IR、1H NMR、MS确认。     

环加成反应制备电活性的富勒烯衍生物

系统地介绍了利用「４＋２」、「３＋２」和「２＋１」环加成反应制备电活性富勒烯衍生物的方法。     

吸电子基团对[60]富勒烯吡咯烷空间结构的理论研究

借助密度泛函量子力学程序对硝基、甲氧基和羟基3种吸电子基团对[60]富勒烯吡咯烷空间结构的影响进行了研究。结果表明,结构优化后的[60]富勒烯吡咯烷衍生物的LUMO与HOMO能量差ΔE并不随基团吸电子能力的增强而增加,吸电子基团对[60]富勒烯衍生物吡咯烷键长和键角的影响大小为NO2>OH>OCH3。     

Photoredox‐Catalyzed Dimerization of Arylalkenes via an Oxidative [4+2] Cycloaddition Sequence: Synthesis of Naphthalene Derivatives

We report a radical cation [4+2] annulation of arylalkenes to afford naphthalene derivatives using an organic photosensitizer (9‐mesityl‐10‐methylacridinium perchlorate) under visible light photocatalysis. In the presence of oxygen (in the air), the oxidative dimerization/intramolecular [4+2] cycloaddition of two alkene molecules provides 3,4‐dihydronaphthalen‐1(2H)‐ones in good to high yields. Under a nitrogen atmosphere, (dihydro)naphthalenes were attained in moderate to excellent yields by using Selectfluor as the oxidant. The transformation proceeds via a tandem dimeric electrophilic addition/Friedel–Crafts cyclization/radical coupling/elimination sequence. This approach represents a mild and straightforward assembly of the naphthalene skeleton using a visible light photocatalytic cascade strategy.

     

Catalytic Asymmetric [3+2] Cycloadditions of C‐3 Unsubstituted 2‐Indolylmethanols: Regio‐, Diastereo‐ and Enantioselective Construction of the Cyclopenta[b]indole Framework

The first catalytic asymmetric [3+2] cycloaddition of 2‐indolylmethanols with 3‐vinylindoles has been established, which makes use of C‐3 unsubstituted 2‐indolylmethanol as a C₃ building block in the presence of a chiral phosphoric acid. By using this strategy, biologically important cyclopenta[b]indole frameworks were efficiently constructed with regiospecificity in high yields (up to 99%), excellent diastereo‐ and enantioselectivities (up to >95:5 dr, 96:4 er). This reaction not only represents the first catalytic asymmetric [3+2] cycloaddition of C‐3 unsubstituted 2‐indolylmethanols, but also has confronted the great challenges in 2‐indolylmethanol‐involved enantioselective transformations.

     

[3+2] Cycloaddition of Propargylamines and α‐Acylketene Dithioacetals: A Synthetic Strategy for Highly Substituted Pyrroles

A new [3+2] cycloaddition strategy for the direct synthesis of highly substituted pyrroles from the readily available α‐acylketene dithioacetals (or related substrates) and commercially available propargylamines under mild metal‐free conditions has been developed. In this reaction, the acyl group plays a critical role in driving the conjugate addition of propargylamine and further cyclization to give pyrroles. Furthermore, the wide scope was confirmed by the preparation of 1,2,3,4‐tetrasubstituted pyrroles (60–70% yields) via a formal 1,2‐acyl migrating [3+2] cycloaddition pathway with N‐methylprop‐2‐yn‐1‐amine as the secondary amine component.     

Mg(II)-Catalyzed [4+2] Annulation for the Synthesis of 2-Arylquinoline Motifs: Applications and DFT Studies

Mg-catalyzed [4+2] cycloaddition reactions between 2-aminobenzaldehydes and ynones offered an array of 2-arylquinoline motifs merged with a CF₃-acyl group. Furthermore, with Mg-catalyzed [4+2] annulation as the key step, DDD107498, DDD102542, and Hit analogues were assembled. Finally, a computational study of the reaction mechanism was conducted.     

Improved Synthesis of 5-Substituted 1H-Tetrazoles via the [3+2] Cycloaddition of Nitriles and Sodium Azide Catalyzed by Silica Sulfuric Acid

A silica supported sulfuric acid catalyzed [3+2] cycloaddition of nitriles and sodium azide to form 5-substituted 1H-tetrazoles is described. The protocol can provide a series of 5-substituted 1H-tetrazoles using silica sulfuric acid from nitriles and sodium azide in DMF in 72%-95% yield.     

富勒烯[60]-3,5-二氯-4-吡啶酮衍生物的合成研究

以3,5-二氯-4-吡啶酮为原料,与对甲苯磺酰肼发生缩合反应生成3,5-二氯-4-吡啶酮对甲苯磺酰腙、再与富勒烯[60]发生[2+1]环加成反应,制备了富勒烯[60]-3,5-二氯-4-吡啶酮衍生物,总产率35.6%。探索了富勒烯[60]与酰腙发生环加成反应的最佳工艺条件。产物结构经IR,1HNMR,MS表征。     

Using a polymer‐supported azide ion in [2+3] cycloaddition reaction of azide ion with nitriles

The [2+3] cycloaddition between various nitriles and crosslinked poly(4‐vinylpyridine) supported azide ion proceeds smoothly in the presence of ammonium bromide or ammonium chloride in N,N‐dimethyl formamide, to give the corresponding 5‐substituted‐1H‐tetrazoles in good to high yields. Conventional heating was used to promote reaction. It was found that using nitriles with electron‐withdrawing groups result in bout higher yields and lower reaction times. The present procedure offers advantages, such as shorter reaction time, and simple workup. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Chiral Dirhodium(II) Carboxamidate‐Catalyzed [2+2]‐Cycloaddition of TMS‐Ketene and Ethyl Glyoxylate

The [2+2]‐cycloaddition reaction between ethyl glyoxylate and trimethylsilylketene is reported. Enantiomeric excesses up to 83% have been achieved with the use of only 1.0 mol % of a previously unreported chiral imidazolidinone‐ligated dirhodium(II) carboxamidate catalyst. An extensive survey of chiral catalysts has shown that enantiocontrol for cycloaddition increases as the steric bulk of the ligand is increased. However, enantioselectivity is increased to 99% ee by the addition of 10 mol % of quinine as a co‐catalyst with a chiral dirhodium(II) azetidinone‐ligated catalyst, and there is a significant decrease in reaction time.