无过渡金属参与下Selectfluor作为“无氟”官能化试剂在有机合成中的应用

Selectfluor是一种性能优越的商品化的亲电氟化试剂,广泛应用于氟化反应中.近年来Selectfluor作为"无氟"官能化试剂在有机合成中得到较广泛的应用,尤其是利用Selectfluor与过渡金属的协同催化体系催化反应,取得了较大的进展.然而,该催化体系存在过渡金属价格昂贵、污染环境等问题.因此, Selectfluor作为"无氟"官能化试剂在无过渡金属参与下的应用受到越来越多的关注.根据反应类型综述了无过渡金属参与下Selectfluor作为"无氟"官能化试剂在有机合成中的应用,并对其前景进行了展望.     

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.     

钯催化Stille交叉偶联反应研究新进展

综述了钯催化Stille交叉偶联反应的最新研究进展, 主要包括三个方面: (1)有机锡化合物与有机亲电试剂如卤代芳香烃、卤代烷烃、酰氯等的反应; (2)Stille反应的机理; (3) Stille反应在有机合成中的应用.     

亲核性氟源在碳碳不饱和键选择性氟化官能化反应中的应用

含氟化合物表现出的特殊理化和生物活性使得其在药物、农用化学品和材料科学等领域有着广泛而重要的应用,因此,含氟化合物的高效制备不仅成为了合成化学的研究热点之一,而且极大地推动了相关领域的蓬勃发展.其中,在有机分子内直接引入氟原子的方法主要有亲电氟化和亲核氟化.相较于亲电氟化,亲核氟化反应所用的氟化试剂通常廉价易得,所需的反应条件也比较温和.作者课题组借助过渡金属催化、可见光氧化还原催化和可见光促进策略,拓展了亲核性氟源在碳碳不饱和键选择性氟化官能化反应中的应用,合成了一系列结构新颖的含氟化合物.在该研究评论中将对此做出小结,并对该领域值得关注的研究方向进行简要的展望.     

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。     

电化学部分氟化芳基研究进展

含氟芳香化合物具有生物活性好、稳定性高、易被生物体代谢等优点,在医药和农药领域有着广泛的用途.目前芳基部分氟化的方法主要分为依赖于氟化试剂的亲电氟化方法以及反应条件苛刻甚至需要过渡金属催化的亲核氟化方法,这些方法操作繁琐并且污染环境.电化学氟化将"电能"作为一种"强氧化剂"来实现氟化反应,是一种直接、绿色且温和的氟化手...     

三甲基硅化腈在有机合成中的应用

三甲基硅化腈是一种常用的有机合成试剂. 对近年来三甲基硅化腈在有机合成中的应用进行了简要的总结和概述, 重点介绍了三甲基硅化腈作为强的亲核试剂广泛用于环氮和环氧化合物的开环反应、亚胺和醛酮类化合物的加成、胺与醛或酮参与的多组分反应、偶联反应以及对炔和具有较高活性的碳碳双键的氰化加成等反应.     

线性二芳基碘盐在杂原子芳基化中的应用研究进展

有机高价碘盐化合物作为一种低毒性、对环境友好、高反应活性的试剂,受到了广泛的关注.线性二芳基碘盐是一类重要的高价碘试剂,常在有机合成中作为芳基阳离子试剂进行芳基化反应,在有机合成领域具有广泛的应用.在温和的条件下,线性二芳基碘盐与亲核试剂反应成为高效构建杂原子芳基化的有效手段之一.按照成键类型分类讨论线性二芳基碘盐在杂原子(包括氧、氮、硫、磷等)芳基化反应中的应用,并就该领域的的发展前景进行展望.     

PhI(OAc)_2参与的β-酮酸酯及β-酮酰胺亲核氟化反应

报道了一种构建含氟的β-酮酸酯及β-酮酰胺的亲核氟化反应.该反应采用Ph I(OAc)_2为氧化剂、3HF·Et3N为氟化试剂,在室温下反应30min高效构建一系列含有季碳中心的含氟化合物.与传统的亲电氟化反应相比,该方法具有无金属参与、反应时间短、反应条件简单、反应收率高等优点.     

离子液体在氟化反应中的应用进展

离子液体作为一类新型绿色溶剂,具有制备简单、稳定性好、溶解能力强、挥发性小、安全性强等优点,因此在有机单元反应包括酯化、氧化、还原、重排反应等中的应用相当广泛,有着十分诱人的应用前景.虽然其在氟化反应中的应用研究开始得较晚,但发展很快,目前在重氮化氟化、亲核氟化、亲电氟化以及电化学氟化等方面都取得了较大的进展.本文综述了近年来离子液体在氟化反应中应用的最新进展情况,并对其未来发展方向和应用前景进行了展望.     

Synthesis of Bis(vicinal Difluorinated) Polyoxyethylene Glycols

The action of tosyl chloride on bisfluorohydrins gives the corresponding tosylates which are converted into bis(vicinal difluorinated) polyoxyethylene glycols by reaction with potassium fluoride and triethylamine tris(hydrofluoride) mixture.     

Microwave-Assisted One-Carbon Chain Extension in the Preparation of Terminal α-Hydroxy Ketones

The microwave-assisted synthesis of terminal α-hydroxy ketones from acid chlorides and tris(trimethylsiloxy)ethylene in the presence of triethylamine is reported. The use of triethylamine had several advantages in the reaction: it increased the reactivity of the acid chloride, acted as a scavenger of the HCl that was produced in the reaction, protected the silylated enol from decomposition, and made the excess use of the silyl reagent unnecessary. Mechanistic effects of triethylamine are discussed. Effects of various base additives, reaction temperatures, reaction times, and solvents in the reaction are compared.     

Synthesis of Non-Symmetric Functionalized Polyfluoroalkyl Phosphites

Two ways for the synthesis of new representatives of non-symmetric organic phosphites with polyfluoroalkyl substituents were developed based on organic dichlorophosphites. The reaction of polyfluoroalkyl dichlorophosphites with allyl alcohol, proceeding at a temperature of –10–22°C (2 h) in the presence of triethylamine, gave diallyl polyfluoroalkyl phosphites in a yield of 75–77%. Under similar conditions (–30–22°C, 2–4 h, Et3N), alkyl (or aryl) dichlorophosphites reacted with polyfluoroalkanols to form alkyl (or aryl) bis(polyfluoroalkyl) phosphites (yield 56–67%). Unlike diallylpolyfluoroalkyl- and alkylbis(polyfluoroalkyl) phosphites, arylbis(polyfluoroalkyl) phosphites are symmetrized under storage conditions (room temperature, inert atmosphere), forming the corresponding triaryl- and tris(polyfluoroalkyl) phosphites.     

Darstellung und Eigenschaften einiger methoxylierter Oligosilane

Preparation and Properties of Some Methoxylated Oligosilanes Tetrakis(trichlorsilyl)silane reacts with methanol and triethylamine to tetrakis(trimethoxysilyl)silane ( I ) or a mixture of I , tris(trimethoxysilyl)silane ( II ), Bis(trimethoxysilyl)silane ( III ) and tetramethoxysilane, depending on the reaction conditions. II is chlorinated to tris(trimethoxysilyl)chlorosilane ( IV ) by CCl₄, IV can be further methoxylated to tris(trimethoxysilyl)methoxysilane ( V ). The compounds I–V are characterized by vibrational, ¹H-nmr-, u.v.- as well as mass spectra.     

Regioselective <Emphasis Type="Italic">N</Emphasis>-alkylation of (2-chloroquinolin-3-yl) methanol with <Emphasis Type="Italic">N</Emphasis>-heterocyclic compounds using the Mitsunobu reagent

The Mitsunobu reaction is a well-established fundamental reaction and has been widely applied in organic synthesis. In this paper, under Mitsunobu conditions dehydration proceeds between (2-chloroquinolin-3-yl)methanol and nitrogen heterocyclic compounds such as quinazolinone, pyrimidone, 2-oxoquinoline in dry THF in the presence of triethylamine, triphenylphosphane and diethyl azodicarboxylate to give the corresponding products. As part of our recent research, we attempted to couple two N-heterocyclic compounds under Mitsunobu reaction conditions to provide efficient building blocks for natural product synthesis.     

The relation of solvent heats of mixing to the enthalpies of proton transfer of some amines in methanol-water mixtures

Enthalpies of reaction for proton transfer in methanol-water mixtures are related to the enthalpies of mixing of methanol and water. The data are direct calorimetric measurements of the standard enthalpies of proton transfer in methanol-water mixtures of varying composition using the bases quinuclidine triethylamine, and tris(hydroxymethyl)aminomethane. Other possible applications of the principle are mentioned.decreased     

A modified procedure for synthesis of the side chain of ceftazidime-activated thioester

A modified procedure for synthesis of the side chain of ceftazidime-activated thioester has been established. This key intermediate of ceftazidime was obtained by a more eco-friendly process than conventional methods, and the yield was much higher (up to 92.4 %). It was found that different organic bases (triethylamine or pyridine) used in this reaction had different effects. The reaction conditions were also optimized to make the route more competitive and suitable for large-scale industrial production.     

相转移催化与微波辐射合成三(2-氰乙基)胺

将微波辐射与相转移催化技术相结合,在加压密闭容器中,以氨水和丙烯腈合成了配位中间体三(2-氰乙基)胺,产率为61.2%,合成时间比传统方法缩短了8倍;在微波辐射下,产率为67.2%,合成时间缩短约90倍.对产物进行了元素分析,IR,¹H-NMR,ES-MS,及TG-DTA表征.     

A dendritic active site: catalysis of the Henry reaction

[reaction: see text] Dendrimers containing an encapsulated tertiary amine were prepared by coupling tris(2-aminoethyl)amine with dendritic branches derived from L-lysine. These dendrimers were used as catalysts in the Henry (nitroaldol) reaction between 4-nitrobenzaldehyde and nitroethane, and their catalytic performance was compared with that of triethylamine. Attachment of the dendritic shell alters the rate of reaction and influences the syn:anti ratio of products. It is proposed that the dendritic shell generates an encapsulated catalytically active site, mimicking the behavior of a protein superstructure.     

Chemoenzymatic Synthesis of Cellular Adhesion Tripeptide RGD Precursor in Organic Media

IntroductionA characteristic tripeptide sequence Arg-Gly-Asp(RGD) that is found within fibronectin and other rela-ted adhesion molecules in extracellular matrices(ECM)has received considerable attention from researcherssince it was proved to be a recognit…