Catalytic Asymmetric Construction of α‐Quaternary Cyclopentanones and Its Application to the Syntheses of (−)‐1,14‐Herbertenediol and (−)‐Aphanorphine

A novel and efficient strategy to build α‐benzylic quaternary cyclopentanones with excellent enantioselectivities (up to 96 % ee) and high yields (up to 99 % yield) has been developed, and its application demonstrated by the first catalytic asymmetric total synthesis of (?)‐1,14‐herbertenediol and the formal synthesis of (?)‐aphanorphine.     

Experimental Investigation on Binary Phase Diagram of the Thermotropic Phase Transitions Compounds (n‐CnH2n+1R3)2ZnCl4

The thermotropic phase transitions compounds (n‐C_nH_2n+1R₃)₂ZnCl₄ as well as a series of their binary mixtures were prepared by a solution reflux method from their ethanol solutions. The experimental subsolidus binary phase diagram of [n‐C₁₈H₃₇N(CH₃)₃]₂ZnCl₄‐[n‐(C₁₈H₃₇)₂N(CH₃)₂]₂ZnCl₄ is constructed over the entire composition range by differential scanning calorimetry(DSC) and X‐ray. Experi‐ mental results indicate one stable intermediate phase [n‐C₁₈H₃₇N(CH₃)₃] [n‐(C₁₈H₃₇)₂N(CH₃)₂]ZnCl₄ at W_C18C3Zn %=59.75 %, and two invariant three phase equilibria, which shows two eutectoid temperatures: Te₁ at 310±1 K for eutectoid point W_C18C3Zn %=36.24 %, Te₂ at 313±1 K for eutectoid point W_C18C3Zn %=80.17 %. These three noticeable solid‐solution ranges are α‐phase at the left, ?‐phase at the right, and ψ‐phase in the middle of the phase diagram. It is (n‐C_nH_2n+1R₃)₂ZnCl₄ systems as phase change materials that are characterized the phase transition temperatures T in the range of 310 to 340 K, the transition enthalpies ΔH in the range of 38.40 and 168.72 J/g between two polymorphic forms.     

Recent Advances on the Total Syntheses of Communesin Alkaloids and Perophoramidine

The communesin alkaloids are a diverse family of Penicillium‐derived alkaloids. Their caged‐polycyclic structure and intriguing biological profiles have made these natural products attractive targets for total synthesis. Similarly, the ascidian‐derived alkaloid, perophoramidine, is structurally related to the communesins and has also become a popular target for total synthesis. This review serves to summarize the many elegant approaches that have been developed to access the communesin alkaloids and perophoramidine. Likewise, strategies to access the communesin ring system are reviewed.     

Diastereoselective Synthesis of Cyclopentanoids: Applications to the Construction of the ABCD Tetracyclic Core of Retigeranic Acid A

A concise and efficient approach for the construction of the tetracyclic carbon skeleton of retigeranic acid A is described. The key transformations include a novel Rh‐catalyzed [3+2] cycloaddition of enyol to afford cyclopentanoid E , bearing two contiguous quaternary stereocenters at the bridgehead positions, and an intramolecular Pauson–Khand reaction to construct the advanced tetracyclic core structure of retigeranic acid A.     

Enantioselective Synthesis of Quaternary Carbon Stereocenters: Addition of 3‐Substituted Oxindoles to Vinyl Sulfone Catalyzed by Pentanidiums

A pentanidium‐catalyzed highly enantioselective conjugate addition of 3‐alkyloxindoles to phenyl vinyl sulfone has been demonstrated. This approach allows the construction of 3,3‐dialkyl‐substituted oxindole frameworks with high yield and excellent enantioselectivity (up to 99 %) under simple phase‐transfer conditions. A variety of oxindoles bearing all‐carbon quaternary stereogenic centers were obtained in the presence of 0.25 mol % pentanidium. Meanwhile, practicality was illustrated by a gram‐scale asymmetric synthesis of two 3,3‐dialkyl‐substituted oxindoles. The resulting adduct can be smoothly transformed to the natural product analogue in a short synthetic route.     

Quaternary Stereogenic Centers through Enantioselective Heck Arylation of Acyclic Olefins with Aryldiazonium Salts: Application in a Concise Synthesis of (R)‐Verapamil

We describe herein a highly regio‐ and enantioselective Pd‐catalyzed Heck arylation of unactivated trisubstituted acyclic olefins to provide all‐carbon quaternary stereogenic centers. Chiral N,N ligands of the pyrimidine‐ and pyrazino‐oxazoline class were developed for that purpose, providing the desired products in good to high yields with enantiomeric ratios up to >99:1. Both linear and branched substituents on the olefins were well‐tolerated. The potential of this new method is demonstrated by the straightforward synthesis of several O‐methyl lactols and lactones containing quaternary stereocenters, together with a concise enantioselective total synthesis of the calcium channel blocker verapamil.     

Synthesis and Spectroscopic Characterisation of 2,3‐Epoxy/ 3‐Chloro‐2‐hydroxy Propyl Derivatives of Quaternary Ammonium Salts:Useful Cationic Fixing Agents

Eight mono-reactive and four bis-reactive 2,3-epoxy/3-chloro-2-hydroxy propyl derivatives of quaternary ammonium salts have been synthesised by reacting epichlorohydrin with suitable tertiary amines and diamines. Mono-reactive derivatives also contain cyano and carboxylic groups in addition to 2,3-epoxy/3-chloro-2-hydroxy propyl groups. The structures of these quaternary ammonium salts have been characterised using IR and ¹H NMR spectroscopic techniques. These quaternary ammonium chlorides have been applied to the cotton fabrics as pretreatments and aftertreatments and promising results have been obtained.     

功能性超薄有序分子沉积膜的制备及其结构研究

1991年G.Decher等首次探讨了阴阳离子与聚电解质交替沉积制备有机超薄膜的方法。我们在完善成膜技术和发展成膜基质的基础上,详细研究了其成膜过程与膜的结构,并定义这种新的自组装超薄有序膜为分子沉积膜——MD膜。MD膜是利用阴阳离子的静电吸附反应特性,通过相反离子体系的交替分子沉积制备的层状有序自组装多层超薄膜。需要指出的是,分子沉积既是有机超薄膜的制备技术,本身又是一种自组装超薄有序膜。MD膜制备工艺简单,热稳定性和长期稳定性好,不受基体形状与面积限制。     

含松香骨架的新型手性季铵盐相转移催化剂的合成及其在不对称环氧化反应中的应用

以天然松香为原料合成了4个新型手性季铵盐类相转移催化剂, 并用于催化不对称查尔酮环氧化反应, 发现这类手性相转移催化剂可以有效地催化查尔酮的不对称环氧化, 环氧化产物ee最高达20%.     

镉汞四元硒化物K8Cd2.79Hg9.21Se16和Rb4Hg3.04Cd2.96Se8的溶剂热合成及表征

利用溶剂热法合成了2种含镉汞的二维(2D)四元硒化物K8Cd2.79Hg9.21Se16(1)和Rb4Hg3.04Cd2.96Se8 (2)。单晶X射线衍射分析表明,化合物1为正交晶系,空间群为Pbcn,a=1.082 71(17) nm,b=0.678 73(10) nm,c=1.415 0(2) nm,Z=1;化合物2为正交晶系,空间群为Ibam,a=0.640 72(10) nm,b=1.160 25(16) nm,c=1.452 0(2) nm,Z=2。化合物1中含有八元环Cd2Hg2Se4和六元环CdHg2Se3阴离子层(Cd2.79Hg9.21Se16)n8n-;化合物2中含有八元环Cd2(Cd/Hg)2Se4及四元环CdHgSe2和(Cd/Hg)2Se2阴离子层(Hg3.04Cd2.96Se8)n4n-。对这2种化合物进行了扫描电镜和能谱分析、粉末X射线衍射、差示扫描量热分析、固体-可见漫反射光谱和荧光性质等表征。