高价碘试剂介导的8-氨基喹啉C(5)位碳-氢键亲核氟化反应

8-氨基喹啉的C(5)位碳-氢键氟化反应近年来受到广泛关注,但大多需要使用过渡金属催化剂和亲电氟化试剂来实现.在高价碘试剂的介导下实现了无过渡金属催化条件下的8-氨基喹啉C(5)位碳-氢键亲核氟化反应.使用廉价易得且安全稳定的氟化银作为亲核氟化试剂,反应无需惰性气体保护,条件简单,操作方便,区域选择性好,底物范围较广,为喹啉类化合物的氟化提供了一种有潜在应用价值的新方法.     

二氟烯醇硅醚参与的高效“在水上”无催化剂亲核加成反应:显著的氟效应

正Angew.Chem.Int.Ed.2014,53,9512~9516尽管C—F…H—X相互作用已通过单晶结构分析和理论计算得以证实,但利用这一弱相互作用来改善有机反应活性的研究才刚起步.最近,华东师范大学周剑课题组设想利用部分氟代的亲核试剂与水分子之间的C—F…H—O相互作用,结合界面水分子对亲电试剂的氢键作用,来实现一些"在水上"的无催化剂反应,为选择性合成含氟化合物提供一些高效方法.基于这一设想,他们发展了"在水上"的无需催化剂的二氟烯醇硅醚1与醛、高活性的酮以     

环硅氧烷开环聚合反应的机理及动力学研究

环硅氧烷在亲核或亲电催化剂、温度或辐射作用下,可开环聚合生成线型聚硅氧烷,聚合方法主要有本体聚合和乳液聚合.本体聚合可分为阴离子聚合和阳离子聚合,阴离子聚合就是在碱性催化剂(亲核试剂)作用下,使环硅氧烷开环聚合成线型聚硅氧烷的过程;阳离子聚合就是环硅氧烷在酸性催化剂(亲电试剂)作用下的开环聚合反应.乳液聚合则是单体和水(或其它分散介质)并用乳化剂配成乳液状态进行聚合,按所采用的乳化剂种类不同,主要有阴离子型和阳离子型两种类型.本文总结了近几年国内外环硅氧烷本体聚合和乳液聚合的开环聚合机理及动力学研究情况,并对今后此方面的研究进行了展望.     

烷基铝试剂与亲电试剂的偶联反应研究进展

烷基铝试剂因其反应活性高、毒性低、易于制备,广泛应用于有机反应中.过渡金属催化或无催化剂的条件下,有机铝试剂与亲电试剂的交叉偶联反应为多种化合物的合成提供了一种简便的方法,并显示出比有机锂和有机镁试剂更高的官能团耐受性,可以在硝基、酯基、羟基、氨基、腈基和内酯的存在下与羰基进行加成反应,与亲电试剂进行偶联反应.近年来许...     

手性Salen-Ti-Ga异核双金属配合物催化的硫酚对环氧化合物的不对称开环反应

Shibasaki小组设计合成了一系列既含有Lewis酸又含有Bronsted碱的双活性中心催化剂,并应用于一系列不对称反应中,取得了巨大的成功.受双活性中心的启发,我们认为选用在同一催化剂分子中,引入两种Lewis酸性不同的软、硬Lewis酸,两种金属就有可能分别导引参加反应的亲电试剂以及亲核试剂,从而既能大幅度地提高反应的选择性,又能提高催化反应的活性及催化剂的效率,我们称之为"软硬Lewis酸协同效应".我们合成了以手性Salen(t-Bu)为配体的镓钛双金属有机化合物,并以此为催化剂催化苯硫酚对环氧化合物的不对称开环反应,反应效果比Salen(t-Bu)镓或钛单核金属有机化合物都有明显的提高.     

铜催化C-N交叉偶联反应的研究进展

对铜催化的C-N交叉偶联反应的最新研究进展作了综述.按照反应中含氮化合物种类的不同将亲核试剂分为氨基酸、胺、酰胺、含氮芳香杂环化合物、其它含氮化合物五类,对各类亲核试剂参与反应的体系(包括亲电试剂、催化剂前驱体、配体、溶剂、温度、碱、反应时间)做了全面归纳,在此基础上以配体为主线对各类亲核试剂涉及的反应进一步做了详细介绍.另外,对这一反应的机理研究也做了综述.     

过渡金属络合物在精细有机合成中的应用

过渡金属化学已发展成为有机合成的重要方法,本文综述了它在精细有机合成中应用的一些进展。叙述了金属有机化合物作为亲电体与亲核试剂反应,金属有机化合物作为亲核体与亲电试剂反应,以及偶合和环化反应。应用这些反应可以巧妙地合成若干天然产物。     

镍催化构筑C(sp3)—C(sp3)键反应研究进展

过渡金属催化的偶联反应是构筑C-C键的高效方法,在有机合成中得到了广泛的应用.然而,相对于Heck反应、Negishi偶联与Suzuki偶联等构筑C（sp²）-C（sp²）键的反应,过渡金属催化的构筑C（sp³）-C（sp³）键的偶联反应较难进行,发展较晚.近年来,烷基-烷基C-C键偶联反应受到广泛的重视,一些高效催化剂被开发出来,其中镍催化剂展示出独特的催化活性和选择性.本文将综述镍催化烷基-烷基C-C键偶联反应最新研究进展,主要包括烷基亲电试剂与金属有机试剂交叉偶联反应、导向基参与的C（sp³）-H键活化的偶联反应、镍-光反应催化剂协同催化偶联反应、烷基亲电试剂与亲电试剂的还原偶联反应和镍催化烯烃加成反应等.     

新型双功能手性硫脲小分子催化剂的合成及其在Michael加成反应中的应用

奎宁和手性氨基醇通过硫脲片段组合,合成了4个新型的具有多氢键供体的双功能手性硫脲类小分子催化剂(5a～5d),其结构经1H NMR,13C NMR,IR和HR-MS表征。以查尔酮为底物,硝基甲烷为亲核试剂,考察了5a～5d在Michael加成反应中的催化活性和对映选择性。结果表明,以Na2CO3为碱,三氯甲烷为溶剂,5c为催化剂,于室温反应24 h,加成产物4-硝基-1,3-二苯基丁烷-1-酮的收率69%,对映选择性86%。     

叔膦促进下两种亲电试剂之间的环化反应研究进展

发展环状化合物的高效合成方法对药物分子、天然产物及其他功能有机分子的合成具有重要意义.近年来,叔膦促进下两种亲电试剂之间的环化反应,由于具有原料简单易得、反应条件温和、且无需金属参与等优点,同时为多种碳环及杂环化合物的合成提供了高效的新途径,因而受到了合成化学家的广泛关注.这类反应通常经过叔膦对亲电试剂进行亲核加成,产生两性离子活性中间体这一关键步骤来完成.根据两性离子的不同来源,综述了叔膦促进下缺电子联烯、Morita-Baylis-Hillman烯丙基化合物、缺电子烯烃与其他亲电试剂之间的环化反应.     

Bisphosphonate prodrugs: synthesis of new aromatic and aliphatic 1-hydroxy-1,1-bisphosphonate partial esters

Methods for the preparation of various 1-hydroxy-1,1-bisphosphonate partial esters were developed. They were obtained from (alkyl or phenyl) bis(trimethylsilyl) phosphite and aromatic or aliphatic acid chlorides, followed by methanolysis.     

A Convenient and Facile Synthesis of O,O-Diphenyl 1-(5-Alkyl-1,3,4-thiadiazol-2-yl) Amino-1-arylmethylphosphonates

Nineteen novel O,O-diphenyl l-(5-alkyl-1, 3,4-thiadiazol-2-yl) amino-1-arylmethylphosphonates were synthesized by the three-component condensation reactions of 2-amino-5-alkyl-1,3,4-thiadiazoles with triphenyl phosphite and aromatic aldehydes in the presence of acetic acid.     

竹炭磺酸催化一锅三组分合成α-氨基膦酸酯

以新鲜竹材为原料,经炭化和磺化制得的竹炭磺酸催化各种芳醛、芳胺和亚膦酸二乙酯一锅三组分合成α-氨基膦酸酯.结果表明:该固体酸具有催化性能好、操作简便、来源广泛和可重复利用等优点.     

Preparation of polyamide-imides via the phosphorylation reaction. II. Synthesis of wholly aromatic polyamide-imides from N-[p-(or m-) carboxyphenyl]trimellitimides and various aromatic diamines

Wholly aromatic polyamide-imides with high molecular weight (η_inh up to 1.7 dL/g in DMAc–5% LiCl) were obtained by the direct polycondensation reaction of N-[p-( or m-) carboxyphenyl]trimellitimide [p-(or m-)CPTMI] and aromatic diamines by means of di- or triphenyl phosphite in N-methyl-2-pyrrolidone (NMP)-pyridine solution in the presence of lithium or calcium chloride. The factors affecting the phosphorylation reaction were investigated, in particular for the reaction of p-CPTMI and 4,4'-oxydianiline (ODA). Molecular weight of polymers varied with the amount of metal salts and showed maximum values at the concentration of 10-15 wt % in the reaction mixture. Monomer concentration of 0.2 mol/L produced polymer of the highest viscosity. Higher concentrations produced gelation and yielded polymers of low molecular weight. A reaction temperature of about 120°C gave the best results. Among the solvents tested, NMP was significantly the most effective for the reaction. The highest inherent viscosity values, η_inh = 1.35 and 1.58 dL/g, were obtained with triphenyl phosphite (TPP)/monomer and diphenyl phosphite (DPP)/monomer molar ratios of 2.0. Excessive addition of phosphites did not cause a serious deleterious effect on the molecular weight of polymer. Polycondensations of several combinations of p-or m-CPTMI and aromatic diamines were carried out with satisfactory results.     

AuBr3-Catalyzed Chemoselective Annulation of Isocyanates with 2H-Azirine

The chemoselective cyclization of isocyanates with 2H-azirine was achieved with AuBr₃ as catalyst. This transfer sets the stage for the synthesis of aromatic oxazole-ureas in a tandem process. The addition of a catalytic amount of phosphite enhances the process enormously. The reaction can also be performed in a one-pot process using benzoyl azide instead of isocyanate under the same conditions. A detailed study on the role of the phosphite that was applied as an additive revealed that only non-coordinated phosphite can reduce gold(III) and that gold(I) coordinated phosphite is not oxidized. Accompanied by the reduction of gold, HBr is generated in situ, which turned out to be the actual promotor in combination with the remaining AuBr₃. The positive effect of acid can be explained by a strong N–Au coordination, which tends to break more easily in the presence of small amount of protic acid in the reaction solution.     

Preparation of sulfonyl aromatic polyamides and copolyamides by means of di- or triphenyl phosphite

High molecular-weight aromatic polyamides were obtained by the direct polycondensation reaction of 4,4′-sulfonyldibenzoic acid (SDA) with various aromatic diamines, by means of di- (DPP) or triphenyl phosphite (TPP) in N-methyl-2-pyrrolidone (NMP)-pyridine solution containing metal salts such as LiCl and CaCl₂. The factors affecting the phosphorylation reaction were investigated, in particular for the reaction of SDA and 4,4′-oxydianiline (ODA). For the polymerization by means of TPP, the optimum conditions are: molar ratio of TPP to diacid, higher than 2.3; concentration of metal salts, 8 wt % LiCl or 6 wt % CaCl₂; reaction temperature, 100°C; and monomer concentration, 0.4 mol/L. For the polymerization by means of DPP, the optimum conditions are: molar ratio of DPP to diacid, higher than 3.8; concentration of metal salts of 8 wt % LiCl or 10 wt % CaCl₂; reaction temperature, 110°C; and monomer concentration, 0.4 mol/L. Copolyamides were also prepared from the reaction of ODA with the mixed diacids of SDA and other dicarboxylic acids such as terephthalic acid, isophthalic acid, and 2,6-naphthalene dicarboxylic acid by using TPP and DPP as the condensing agents.     

Efficient synthesis of N-alkyl-2,7-dihalocarbazoles by simultaneous carbazole ring closure and N-alkylation

The N-alkyl-2,7-dihalocarbazole as the main product was formed by the reaction of 4,4′-dihalo-2-nitrobiphenyl with aromatic nitro compound and trialkyl phosphite. The presence and crucial role of aromatic nitro compound causes simultaneous carbazole ring closure and N-alkylation unlike the Cadogan ring closure where non-alkylated carbazole is formed as a main product. In addition, the mixture of aromatic nitro compound and trialkyl phosphite was found to be a possible N-alkylating agent for heterocycles, such as carbazole or indole.     

Separation of oxyanions of phosphorus by single column ion chromatography

Separation of mixtures containing hypophosphite, phosphite, orthophosphate, chloride, nitrate and sulphate ions has been achieved using a Vydac 300 IC 405 column, refractive index detection and eluents which were 2mM in p-hydroxy benzoic acid or 4mM in p-amino benzoic acid (adjusted to ph 5.5). Calibration curves were linear over the concentration range 3 to 30 mg P/l.; and the precision (RSD for peak heights in mixtures) was < +/- 10%. Using p-hydroxy benzoic acid, detection of eluted peaks by indirect UV absorption was equally satisfactory. In an initial survey, the elution behaviour of nine oxyanions of phosphorus (simple ions and condensed species) was examined, using eluents containing different organic carboxylic acids (six aliphatic and nine aromatic), present at levels of 1 to 5m(M); with the pH adjusted to values between 3 and 8.6. No suitable conditions for separating mixtures containing condensed phosphates were identified.     

磺酰脲的类Mannich反应研究

研究了对甲苯磺酰脲与取代苯甲醛及亚磷酸二酯的类Mannich反应,用竞争反应的方法对不同胺组分发生类Mannich反应的活性进行了比较.合成了一系列α-对甲苯磺酰脲基磷酸二酯的化合物.产物的结构得到¹HNMR和元素分析的证明.初步生物活性测定结果表明其中某些化合物具有很好的抗烟草花叶病毒活性。     

Effect of initiation conditions on the direct polycondensation reaction using triphenyl phosphite and pyridine

In a model reaction of terephthalic acid with aniline by using triphenyl phosphite in a mixed solvent of pyridine and N-methylpyrrolidone (NMP), mono- and dianilides were produced with relative yields varying with the content of pyridine in the solvent. The polycondensation of terephthalic acid with aromatic diamines was found to proceed more favorably via monoamidation, and highmolecular-weight polyterephthalamides were prepared by controlling initiation conditions (selective activation of carboxylic groups), such as initial solvent systems, including the amount and kind of pyridines and initiation temperatures.