New optically active organotin compounds for heterogeneous bimetallic catalysis

Chiral tin(IV) derivatives with two or three chiral centers adjacent to the metal (−)-Ment₂SnMe₂, (−)-Ment₂SnPh₂, (−)-Ment₃ SnCl, (−)-Ment₃SnH; (−)-Ment = (1R, 2S, 5R)-1-chloro-5-methyl-2-isopropylcyclohexane, R₂Sn[CH(Me)(n-Hex)]₂ (R = Bu or Ph) have been prepared either by the coupling of methylmagnesium chloride with tin halides or by the reaction of lithium stannates with optically active (2-octyl)tosylate. The stereospecificity of both processes was remarkably high, leading to new optically pure organotin reagents which have been fully characterized.     

Optically active ruthenium porphyrins: chiral recognition and asymmetric catalysis

The current applications of ruthenium porphyrins in stoichiometric and catalytic asymmetric reactions are reported. Chiral recognition of racemic phosphines, isocyanides and amino esters has been studied by ¹H-NMR. Experimental investigations of the oxidation mechanism of racemic phosphines and amino esters are described. The stereochemistry of catalytic asymmetric oxidation and cyclopropanation of olefins with optically active ruthenium porphyrins are also discussed.     

Optically active 4-aryl-4-trifluoromethyl-4H-1,3-oxa(thia)zines

S(−)-4-Aryl-4-(N-acylamino)-5,5,5-trifluoropentan-2-ones have been reacted with phosphorus pentachloride and pentasulfide to yield S(−)-4-aryl-4-trifluoromethyl-4H-1,3-oxazines and S(+)-4-aryl-4-trifluoromethyl-4H-1,3-thiazines, respectively.     

Convenient methods for the synthesis of pentacyclic fused heterocycles with coumarin moiety

This review describes the preparation of pentacyclic fused heterocycles with the coumarin moiety. These derivatives are reported as biologically active compounds.     

旋光性高分子的合成（下）

旋光性高分子的合成（下）刘引烽，华家栋（上海科技大学化学系，上海，２０１８００）４不对称聚合由外消旋手性单体制备旋光性高分子必须通过选择性聚合才能实现。选择性聚合是指外消旋的两个对映异构单体进行聚合时，由于体系中存在着某种不对称的诱导因素，其中之一比...     

旋光性高分子的旋光能力（下）

在（上）中，我们讨论了结构单元及其远程作用对旋光性高分子旋光能力的影响。由于高分子具有特殊的长链结构，因而链形态对旋光能力的贡献尤其引人注目。     

光学活性金属卟啉的磁手性效应研究

磁光学活性与自然光学活性均可用介质对左右圆偏振光的吸收之差来表示 .但自然光学活性和磁光学活性的物理机制是截然不同的 ,前者源于镜象不能互相重叠介质的非定域光学响应 ( nonlocaloptical response) ,而后者则是由于介质的时间反演对称性 ( time- reversal symmetry)被磁场打破所致 .理论分析表明 ,当介质的两种光学活性同时存在时 ,将会出现一个新的附加光学效应 ,这种磁光学活性与自然光学活性之间的交叉效应称为磁手性效应 ( magneto- chiral effect)或磁手二色性 ( magneto-chiral dichroism) [1,2 ] .磁手性效应通常很弱 ,直到 1…     

Isolation, absolute configuration, and chiral crystallization of optically active seleninic acid

An optically pure seleninic acid was isolated as stable crystals for the first time by chiral crystallization. The relationship between the absolute configurations and the circular dichroism spectra of the enantiomers could be determined by X-ray crystallographic analysis.     

具有实验抗癌活性的二烃基锡衍生物的研究进展

自从Crown报道了一些二烃基锡衍生物具有抗癌活性以来, 这一领域的研究引起了人们极大的兴越。许多二烃基锡衍生物被制备得到, 并且测定了它们在离体及活性情况下的抗癌活性。本文综述了二烃基锡衍生物抗癌活性的研究进展,包括化合物的结构类型, 抗癌作用机制以及利用QSAR方法对有机锡化合物的抗癌活性进行计算预测等。     

含联萘基团的旋光性聚喹啉的合成与性质

由2，2′－二甲氧基－1，1′－联萘 了旋光活性的2，2′－二甲氧基－6，6′－二乙酰基－1，1′－联萘(DMDABN），经元素分析，NRM，IR和MS等方法对其进行结构表征，DMDABN与3，3′-二苯甲酰基－4，4′二氨基－二苯基醚通过Friedlander反应合成了旋光性聚喹啉，所制备的聚喹啉具有较高的玻璃化转变温度（474－578K），热分解温度（703－770K），很好的耐溶性能和较强的旋光活性。     

Palladium mediated activation of C-F bonds in 2,4,6-trifluoropyrimidine: Synthesis and structure of palladium pyrimidyloxy and pyrimidinone derivatives

[PdMe₂(dcpm)] (1) reacts with 2,4,6-trifluoropyrimidine in the presence of water to give the palladium derivative [PdMe{4-C₄N₂F₂H(O)}(dcpm)] (2). When additional triethylamine is present complex [PdMe(2-OC₄N₂F₂H)(dcpm)] (4) in addition to 2 is formed. Compound 2 converts slowly into the binuclear complex [Pd{4-C₄N₂F₂H(O)}(μ-dcpm)]₂ (5). The molecular structure of 5 was determined by X-ray crystallography. The palladium-palladium distance is 2.5898(3) Å.     

Stereoselective synthesis of optically active mono and diaminoalcohols

Several optically active mono and diaminopolyols have been synthesized starting from the octadienedioate 1, by regio- and stereo selective azidation of the corresponding alcohol by Mitsunobu/S_N2 substitution.     

多功能光学活性丁二醇衍生物的合成和结构

通过新的合成策略,以手性合成子3和具有生物活性的有机碱类化合物4为反应底物,利用Michael不对称加成反应,合成得到光学纯的5-(R)-［(1R,2S,5R)-(-)-氧基］-4-(R)-(杂环碱基)-2(5H)-呋喃酮(5). 加成物5通过还原反应得到了多功能光学活性的二醇类化合物6,产率为42%~82%,e.e.≥98%. 化合物6的化学结构得到了确认,其立体化学结构和绝对构型经X射线晶体学测定得到了确定.     

Synthesis of aromatic tetracyclic tin compounds by template and transmetallation reactions: Alkyl vs aryl migration from tin to nitrogen

The syntheses of [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)amine]diphenyltin (1) and [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)amine]dichloro-phenyl-stannate (2) by template reactions using 3,5-di-tert-butylcatechol, aqueous ammonia and SnPh₂Cl₂ are reported. We also report the syntheses of compounds 2, [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)amine]trichloro-stannate (4), [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)methylamine]chloro-methyltin (5), and [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)-n-butylamine]n-butyl-chlorotin (6) and [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)amine]n-butyl-dichloro-stannate (7), performed by transmetallation reactions of the octahedral zinc coordination compound Zn[3,5-di-tert-butyl-1,2-quinone-(3,5-di-tert-butyl-2-hydroxy-1-phenyl)imine]₂ (3) with SnPhCl₃ or SnPh₂Cl₂, SnCl₄, SnMe₂Cl₂, Sn(nBu)₂Cl₂ and Sn(nBu)Cl₃, respectively. The X-ray diffraction structures of compounds 1, 2, 4 and 6 are reported. The transmetallation reactions with Sn(alkyl)₂Cl₂ afforded pentacoordinated tin compounds, where an alkyl group migrated from tin to nitrogen, while similar reactions with Sn-Ph compounds did not present any phenyl group migration.     

光学活性有机钛试剂与苯甲醛不对称加成反应

光学活性二醇（１Ｒ，２Ｒ）－（＋）－１，２－二苯基－１，２－乙二醇（Ⅲａ）和（２Ｒ，３Ｒ）－（－）－１，１，４，４－四苯基－２，３－（缩丙酮）－１，４－丁二醇（Ⅲｂ）分别修饰Ｔｉ（ＯＰｒｉ）３Ｃｌ，再与甲基锂和乙基锂进行烷基化，制备出新的手性有机钛试剂Ⅱａ和Ⅱｂ，然后与苯甲醛进行加成，所得１－苯基乙醇（Ⅳａ）和１－苯基丙醇（Ⅳｂ）的光学收率分别为２５～６５％ｅ．ｅ．和１０～２０％ｅ．ｅ．。简单讨论了Ｃ２－对称型二醇对立体选择性及反应条件的影响     

脂酶催化及其在光学活性有机化合物合成中的应用

讨论了脂肪酶的一般特性，介绍了它们在制备光学活性天然产物以及在医药、农药等方面的应用。     

The regioselective synthesis of monomethoxynaphthylene diacetates

Methods for the conversion of 1,4,5-naphthalenetriols into the corresponding monomethoxy diacetates are described. All utilise the formation of peri-bridged intermediates.     

Optically active tertiary alcohols by biocatalysis

Initially, chemoenzymatic route to optically active aromatic ring-fused cyclic tertiary alcohols (S)-(–)-1-methyl-1,2,3,4-tetrahydronaphthalen-1-ol-(–)-1b, (S)-(+)-1-methyl-2,3-dihydro-1H-inden-1-ol-(+)-1a has been reported.^[9 Özdemirhan, D.; Sezer, S. Sönmez, Y. Tetrahedron Asymmetry 2008, 19(23), 2717–2720.[Crossref], [Web of Science ®] , [Google Scholar]^] CAL-A (lipase-A from Candida antarctica) was found the best biocatalyst for 1b, CAL-A cross linked enzyme aggregate (CLEA) for 1a, with ee values of 20 and 45% and the esters 2b and 2a with ee values 99 and 71%. Then, cyclopent-2-ene anchored tertiary allyl 1a′, homoallyl 1b′ and homopropargyl 1c alcohols have been enzymaticly resolved in a high ee (up to 90%) with 44, 40, and 43% chemical yield, respectively, cyclohex-2-ene anchored tertiary allyl 3a, homoallyl 3b, and homopropargyl 3c alcohols in high ee (up to 97%) too with 42, 45, and 49% chemical yield in turn. Chiral dienes yield the spirocyclic dihydropyrans through ring-closing methathesis with 74 and 78% chemical yields with 90 and 97% ee. Chiral enynes afford the cyclopentenone pyrans through Pauson–Khand reaction with 80 and 81% chemical yields as single diastereomers as reported subsequently.^[1a (a) Tanyeli, C.; Özdemirhan, D. Tetrahedron Asymmetry 2014, 25(8), 658–666; (b) Gassoline, F.; Britton, R. A.; Mowat, J.; O’shea, P. D.; Davies, I. W. Synlett 2007, 14, 2193–2196; (c) Garcia, C.; Martin, V. S. Curr. Org. Chem. 2006, 10(14), 1849–1889; (d) Fujino, A.; Asano, M.; Yamaguchi, H.; Shirasaka, N.; Sakoda, A.; Ikunaka, M.; Obata, R.; Nishiyama, S.; Sugai, T. Tetrahedron Lett. 2007, 48(6), 979–983.[Crossref], [Web of Science ®] , [Google Scholar]^]     

旋光性聚合物的铁电性能

旋光性高分子在结构上具有一定的空间特异性,因而可以有多种应用。根据铁电材料所必需具备的条件,经过特定的分子结构设计,可以使之具备铁电性能,据此,人们已合成了许多不同类型的铁电聚合物。本文按照铁电聚合物所处的聚集态不同,分别综述了具有铁电特性的晶态和液晶态旋光性聚合物的种类、结构特点及其铁电性能,分析讨论了影响液晶态旋光性聚合物的自发极化率和响应时间的因素。