有机锡化合物在天然产物合成中的应用

综述了有机锡化合物在不同对称合成天然产物中的应用。有机锡化合物应用于天然产物的不对称合成,反应条件温和、活性高,有很高的立体选择性和区域选择性,有广阔的应用前景。     

Synthesis,characterization and cytotoxicity of fluorescent organotin complexes of terpyridine derivatives

Five organotin complexes of terpyridine derivatives were synthesized and characterized. The mononuclear Sn（IV） complexes were six-coordinated adopting a distorted octahedral coordination geometry. A brief outline of the fluorescence spectra and the in vitro cytotoxicity of the Sn（IV） complexes have been given.     

有机锡在不对称合成中的应用研究进展

金属有机化合物是不对称合成中常用的有机试剂。有机锡试剂易于制备，而且碳-锡键又易于断开，因此它们被广泛应用于有机合成中，当然也是不对称合成常用的试剂之一，是制备某些手性天然产物必备的试剂。由于锡的结构特点，它可以形成四配位、五配位甚至六配位的配合物，这些配合物作为路易斯酸可用作不对称合成中的催化剂、助催化剂。从已报道的文献看，大多数反应的产率及对映体选择性都在中等或中等以上水平，某些已达到了优良的水平。本文综述了有机锡作为反应试剂、催化剂、助催化剂在不对称合成中的应用。     

Synthesis and characterization of stannacyclododecane-yl-dithiocarbamates

Thirteen new stannacyclododecane dithiocarbamate complexes have been prepared by reacting 12-chloro-12-n-butyl-1,11-dioxa-4,8-dithia-12-stannacyclododecane (1) and 12-chloro-12-n-butyl-1,4,8,11-tetrathia-12-stannacyclododecane (2) with pyrrolidine-, morpholine-, thiomorpholine-, piperidine-, piperazinebis-, and 3-pyrroline-carbodithioates, respectively, as well as with diethyl-dithiocarbamate. All complexes were characterized by elemental analyses, IR, EI-MS, and NMR (¹H, ¹³C, and ¹¹⁹Sn) studies. The spectroscopic data suggest the replacement of the chlorides by the corresponding dithiocarbamates with monodentate coordination, leading to six-coordinate tin atoms in all the cases.     

Synthesis of C-Disaccharides An Unusual Ring Closure Reaction

Abstract

Reaction of the 4-C-lithiomethyl intermediates, obtained from 4-deoxy-4-C-iodomethylglucopyranosides 5a,b, with open-chain glucose derivative 8 afforded 4-deoxy-4-C-heptitylglucopyranosides 9a,b. Mesylation of the newly generated hydroxy group and then desilylation gave 11a,b which were subjected to ring closure under basic conditions. Surprisingly, no C-bridged cellobiosides 12a,b (or, alternatively the corresponding maltosides) were obtained as major products; with loss of one benzyl alcohol residue the furanosides 13a,b were preferentially formed. Their generation and structural assignment is discussed.     

Synthesis and Characterization of Diphenyltin(IV) Dicarboxylates Containing Germanium

Twelve new germanium substituted diphenyltin dipropionates with the general formula (R¹GeCHR²‐CHR³COO)₂SnPh₂ where R¹ = N(CH₂CH₂O)₃, (C₆H₅)₃ and (CH₃C₆H₄)₃, R² = H, CH₃, C₆H₅, p‐CH₃C₆H₄, p‐CH₃OC₆H₄, p‐ClC₆H₄, and R³ = H, CH₃ have been synthesized by the reaction of diphenyltin oxide with a germanium substituted propionic acid. All the compounds were characterized by elemental analysis, IR, multi‐nuclear (¹H, ¹³C, ¹¹⁹Sn) NMR and Mössbauer spectroscopies as well as mass spectrometry. The in vitro antibacterial activity of selected compounds is also reported.     

Synthesis and characterization of some organo-all-tin dendrimers with different peripheral substituents

The synthesis of the first all-tin-dendrimer Sn[(CH₂)₄SnPh₃]₄ (2) results from complete hydrostannation of tetra(but-3-enyl)stannane (1) with triphenyltin hydride. Selective cleavage of one phenyl group from each dendron of 2 with anhydrous HCl results in Sn[(CH₂)₄Sn(Cl)Ph₂]₄ (3), which on treatment with LiAlH₄ yields the corresponding hydride derivative Sn[(CH₂)₄Sn(H)Ph₂]₄ (4) containing four reactive Sn-H bonds. The cyclopentadienyl derivative Sn[(CH₂)₄Sn(C₅H₅)Ph₂]₄ (5) as well as the transition metal substituted derivatives Sn[(CH₂)₄Sn{Co(CO)₄}Ph₂]₄ (6), Sn[(CH₂)₄Sn{Fe(CO)₂C₅H₅}Ph₂]₄ (7), and Sn[(CH₂)₄Sn{Mn(CO)₅}Ph₂]₄ (8) have been prepared by coupling of 3 with the appropriate Grignard or sodium derivatives of the transition metal moieties. The new compounds were characterized by elemental analyses, IR, ¹H-, ¹³C- and ¹¹⁹Sn NMR spectroscopy and MALDI-TOF mass spectrometry.     

Organocobalt Compounds in the Synthesis of Pyridines–An Example of Structure-Effectivity Relationships in Homogeneous Catalýsis

The cocyclization of alkynes with cyano compounds using organocobalt catalysts of the type [YCoL] has evolved into a versatile and technically useful method for synthesizing pyridine and its derivatives. An important advance came with the realization that the organo group Y remains attached to the cobalt throughout the catalytic cycle. This opened up the possibility of optimizing the catalyst by varying the controlling ligand Y.     

有机锡聚合物的合成及应用

介绍了有机锡聚合物的研究现状。重点介绍了有机锡聚合物的各种合成方法及其在海洋防污涂料、木材防腐保护、荧光染料和聚合物改性等方面的应用。     

Synthesis and Characterization of Tri(organotin)Substituted Heteropolytungstates

ＳｙｎｔｈｅｓｉｓａｎｄＣｈａｒａｃｔｅｒｉｚａｔｉｏｎｏｆＴｒｉ（ｏｒｇａｎｏｔｉｎ）ＳｕｂｓｔｉｔｕｔｅｄＨｅｔｅｒｏｐｏｌｙｔｕｎｇｓｔａｔｅｓＹＡＮＧＱｉ－ｈｕａ,ＤＡＩＨｕｉ－ｃｏｎｇ,ＬＩＵＪｉｎｇ－ｆｕ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍ...     

An Unusual Aminal Derivative from a Misdirected Gabriel Synthesis

N-(2-Bromoethyl)phthalimide (1) was reacted with sodium imidazolate in DMF to give the novel aminal N-[1-(1H-imidazol-1-yl)ethyl]phthalimide (4a) as well as N-vinylphthalimide (3) and the desired Gabriel intermediate 2. Aminal 4a as well as heterologues 4b - d form directly from reaction of 3 with the appropriate heterocyclic sodium salt.     

固体碱连续催化合成假性紫罗兰酮

国外多由柠檬草油或氧化芫荽油合成紫罗兰酮,而中国则以富含柠檬醛的山苍子油为原料。其中假性紫罗兰酮(1)是由柠檬醛(2)与丙酮(3)经醇醛缩合而成的。     

Unusual pathway of the tantalum-catalyzed carboalumination reaction of alkenes with triethylaluminum

Carboalumination of 1-alkenes (1-hexene, 1-octene, 1-decene) with Et₃Al in the presence of catalytic amounts of TaCl₅ results in a mixture of 2-(R-substituted)- and 3-(R-substituted)-n-butylaluminums (1:1 ratio) in total yields of 75–85%. The TaCl₅-catalyzed reaction of bicyclo[2.2.1]hept-2-ene, endo-tricyclo[5.2.1.0^2,6]deca-3,8-diene, and (exo/endo)-5-methylbicyclo[2.1.1]hept-2-ene with Et₃Al leads to the formation of diethyl[2-exo-(2′-norbornylethyl)]aluminums in high yields. DFT calculations confirm the thermodynamic preference of the final exo product. The multistep reaction mechanisms for the formation of the resultant organoaluminums through tantalacyclopentanes as key intermediates are also discussed.     

Unusual Au(III)-catalyzed dimerization of benzoxazol-2-yloxy enynes: Formation of substituted 1,5-cyclooctadienes

Symmetric 1,5-cyclooctadienes were formed via Au-catalyzed dimerization of benzoxazol-2-yloxy enynes, involving double nucleophilic attacks of alkenylgolds toward allylic cations.     

Synthesis of N-Glycosides by Silver-Assisted Gold Catalysis

The synthesis of N-glycosides from stable glycosyl donors in a catalytic fashion is still challenging, though they exist ubiquitously in DNA, RNA, glycoproteins, and other biological molecules. Herein, silver-assisted gold-catalyzed activation of alkynyl glycosyl carbonate donors is shown to be a versatile approach for the synthesis of purine and pyrimidine nucleosides, asparagine glycosides and quinolin-2-one N-glycosides. Thus synthesized nucleosides were subjected to the oxidation–reduction sequence for the conversion of Ribf- into Araf- nucleosides, giving access to nucleosides that are otherwise difficult to synthesize. Furthermore, the protocol is demonstrated to be suitable for the synthesis of 2’-modified nucleosides in a facile manner. Direct attachment of an asparagine-containing dipeptide to the glucopyranose and subsequent extrapolation to afford the dipeptide disaccharide unit of chloroviruses is yet another facet of this endeavor.     

由果糖催化合成5-羟甲基糠醛的研究进展

5-羟甲基糠醛(HMF)是一种具有重要应用价值的原材料和中间体,以果糖脱水合成HMF具有实现生物质转化利用的重大意义。本文综述了近三年来果糖制备HMF过程的两大关键因素:催化剂和反应介质的重要进展。固体酸(特别是杂多酸及其盐)、离子液体(ILs)中添加卤化物或ILs作为催化剂是近几年来研究的热点,固体酸的优点是可多次重复使用且易于分离,而ILs中果糖的降解条件较温和,副反应较少。目前,用于果糖转化HMF的反应溶剂优、缺点并存。最后对该反应存在的问题和今后的研究进行了总结和展望。     

Diorganotin 2-fluorocinnamates and 4-fluorophenylacetates: Synthesis,characterization and in vitro antitumour activity

The synthesis and characterization by spectroscopy of several new di-n-butyltin and diethyltin 2-fluorocinnamates and 4-fluorophenylacetates are described. In vitro tests on two human tumour cell lines, MCF-7, a mammary tumour, and WiDr, a colon carcinoma, showed that two of these compounds are more active than cisplatin. Other in vitro tests performed by the NCI, USA on a panel of human tumour cell line show that one of them, bis[di-n-butyl(2-fluorophenylacetato)tin] oxide, is characterized by statistically significant D, D_TGI and D sensitivities, but non-significant D_H and MGD_H selectivities, whereas the analogous 2-fluorocinnamate shows no such significant values.     

3,4—亚甲二氧基苯甲酸锡酯的合成及表征

３，４－亚甲二氧基苯甲酸及其取代物与三苯基氢氧化锡或二丁基化锡反应合成了５个锡酯，通过元素分析，ＩＲ和＾１ＨＮＭＲ对其进行了表征。     

Electron-Poor Acridones and Acridiniums as Super Photooxidants in Molecular Photoelectrochemistry by Unusual Mechanisms

Electron-deficient acridones and in situ generated acridinium salts are reported as potent, closed-shell photooxidants that undergo surprising mechanisms. When bridging acyclic triarylamine catalysts with a carbonyl group (acridones), this completely diverts their behavior away from open-shell, radical cationic, ‘beyond diffusion’ photocatalysis to closed-shell, neutral, diffusion-controlled photocatalysis. Brønsted acid activation of acridones dramatically increases excited state oxidation power (by +0.8 V). Upon reduction of protonated acridones, they transform to electron-deficient acridinium salts as even more potent photooxidants (*E_1/2=+2.56–3.05 V vs SCE). These oxidize even electron-deficient arenes where conventional acridinium salt photooxidants have thusfar been limited to electron-rich arenes. Surprisingly, upon photoexcitation these electron-deficient acridinium salts appear to undergo two electron reductive quenching to form acridinide anions, spectroscopically-detected as their protonated forms. This new behaviour is partly enabled by a catalyst preassembly with the arene, and contrasts to conventional SET reductive quenching of acridinium salts. Critically, this study illustrates how redox active chromophoric molecules initially considered photocatalysts can transform during the reaction to catalytically active species with completely different redox and spectroscopic properties.