硝基芳环和硝基杂芳环中氢的替代亲核取代

氢的替代亲核取代反应(VNS)是与硝基芳环的亲电反应、亲核反应不同的一种新反应. 将VNS与硝基芳环的亲电反应、亲核反应做比较, 阐述了VNS的定义; 通过对竞比实验、速控步骤和动力学同位素效应的分析, 解释了VNS的反应机理; 分别从硝基芳环的结构、亲核试剂的类型和反应条件三方面讨论了影响VNS定位效应的因素; 介绍了VNS反应的应用, 尤其是VNS胺化反应在军事化学中的实际应用.     

Synthesis and Crystal Structure of rac-N,N-Dimethyl-1- ferrocenylethylamine Hydrochloride

Ferrocene with planar chirality are of increasing importance in the synthesis of chiral ligands used in asymmetric catalysis and asymmetric synthesis.[1～3] To prepare Ugi type of chiral base, the most common method is the resolution of rac-N,N-dimethyl- 1-ferrocenylethylamine (1).     

仿生催化剂——Salen金属络合物催化不对称环氧化烯烃的基础

Salen与卟啉、Salen金属络合物与卟啉铁的结构和性质相似, 因此可将Salen金属(Salen-M)络合物认为是仿生催化剂, 它们的仿生性突出表现在不对称催化反应中的高对映异构选择性. 重点介绍了Salen-M络合物催化环氧化烯烃的反应机理, 环氧化合物的对映选择性与Salen配位体中的取代基效应(以取代常数σ_p表示)之间呈线性关系. 另外, 对映异构选择性的高低还与催化剂配体和底物的结构以及反应条件有关.     

Novel Synthesis of Ferrocenyl Schiff Bases and Crystal Structure

Ferrocenylimines have attracted additional interest due to their versatile utilities. They have been widely used as plant growth regulator, bactericide, fuel dope and new anticarcinogen.[1] And a large amount of ferrocenyl shiff bases were prepared in the past. However, study on ferrocenylimines as directing ortho metalation group (DMG) in the (-)-sparteine meditated synthesis of planar chiral ferrocene has not been reported. Herein, we synthesized a series of ferrocenyl schiff bases for this study.     

Solid-state structure of a 1:1 adduct of 2-<Emphasis Type="Italic">t</Emphasis>-butylphenol and 3-<Emphasis Type="Italic">t</Emphasis>-butylsalicylaldehyde

The co-crystal structure of 2-t-butylphenol with 3-t-butylsalicylaldehyde (1) was obtained by single-crystal X-ray diffraction. 2-t-Butylphenol was co-crystallized with 1 equivalent of 3-t-butylsalicylaldehyde. The phase crystallizes in the monoclinic system with P2₁/c space group. The unit cell dimensions are a = 12.351(3) Å, b = 15.253(3) Å, c = 10.377(2) Å, β = 97.58(3)^∘, V = 1937.8(7) ų and Z = 4. The structure of the crystal layered by nonpolar group includes strong intramolecular and weak intermolecular hydrogen bonds. The aldehyde oxygen O2 accepts a three-centered bond through intramolecular O1–H1A⋅sO2 and intermolecular O3–H3A⋅sO2 interactions. In addition, the crystal consists of right-handed helical (P) and left-handed helical (M) chains linked by hydrogen bonding.     

E-苯甲酰二茂铁亚胺的合成、晶体结构和反应性

由苯甲酰二茂铁和一系列伯胺出发,用4A分子筛作为催化剂合成了6种相应的E-构型亚胺化合物,产率为50%～85%.该方法具有很好的通用性,同时适用于芳胺和脂肪胺,并且对杂原子具有耐受性.与文献中使用Al2O3作为催化剂的方法相比,该方法可使反应时间和催化剂的活化时间均大大缩短.所合成的席夫碱用于探索生物碱(一)-Sparteine促进的对映选择性地合成平面手性二茂铁中的反应性.根据所测定的化合物3d晶体结构数据,分析了这类化合物反应活性低的原因是空间位阻所致.而空间位阻较小的二茂铁醛亚胺用于该反应能够顺利进行.