钯催化的烯烃异构化反应

烯烃异构反应可以从简单烯烃出发,通过对碳碳双键立体选择性或者位置选择性调控,实现内烯烃化合物尤其其他方法难以构建的多取代烯烃的高效合成,原子经济性高.详细介绍了钯催化烯烃异构化反应的反应机制,系统总结了钯催化的烯烃顺反异构和位置选择性异构反应,以及其在药物分子和天然产物合成中的应用.     

钯催化的酸酐C—O键的活化及反应

综述了钯催化的酸酐碳——氧键的活化和反应，及由羧酸直接制备相应的醛、酮且不需要卤原子和碱参与的方法。     

为什么叁键比双键易进行亲核加成?

通过比较不同杂化状态的不饱和碳的“供电”能力、亲核加成反应活性中间体的稳定性，从理论上解释叁键比双键易进行亲核加成反应。并通过实例加以说明。     

新型P,N-配体的合成及其在钯催化碳-氮键偶联反应中的应用

以三苯基膦为母体骨架,设计合成了在苯环上连有环状仲胺取代基的五种新型P,N-配体(L1～L5),利用核磁共振谱(1H,13C,31p)、红外光谱、高分辨质谱和X射线单晶衍射等对配体进行了表征,并将它们应用于Pd催化的C-N键偶联反应中.结果表明,三(2-吗啉基苯基)膦(L5)与三(二亚苄基丙酮)二钯(Pd2(dba)3...     

钯催化的2-苯氧基吡啶导向的脱羧酯基化反应研究

发展了一种高效的通过钯催化导向碳-氢键活化的策略在苯环上引入酯基官能团的方法.草酸单乙酯钾盐在过硫酸钾和碳酸银的协同作用下脱羧生成酯基自由基,然后酯基自由基加成到钯环上,最后经过还原消除的过程实现了2-苯氧基吡啶苯环的邻位酯基化.该反应为合成一系列水杨酸乙酯衍生物提供了一种切实有效的途径.     

光学活性脯氨酸催化的不对称有机合成反应

总结了D-或L-脯氨酸作为光学活性有机分子催化剂催化的涉及C＝O, N＝N, C＝N或N＝O键不对称Aldol型反应和α,β-不饱和烯酮及硝基烯烃的不对称共轭加成反应.     

钯催化惰性碳-氢键胺化反应研究进展

胺化反应是有机化学中最重要的反应之一,近年来,过渡金属催化的碳-氢键胺化反应已经成为合成有机胺化物的重要方法.本文综述了钯催化碳-氢键胺化反应的研究进展,按照底物类型和所活化碳-氢键的类型进行分类,并对该领域目前存在的局限性和未来发展进行了总结和展望.     

钯催化的乙炔双羰化-高效合成丁烯二酸二甲酯

报道了无酸和重金属盐的催化乙炔双羰化反应的钯催化体系(催化剂组成为PdCl2/KI).正交实验表明空气的初始分压和助剂KI的用量在乙炔双羰化反应中起着重要的作用.在相同的实验条件下,发现催化体系为PdCl2/HCl/CuCl2和PdCl2/H2SO4/FeCl3时,顺、反丁烯二酸二甲酯的总收率分别为15.3％和21.8％,而用PdCl/KI时总收率达到了81.9％.在最优反应条件下,即PdCl2 0.056 mmol,KI 0.677 mmol,总压5.3 MPa,70℃反应3h,顺、反丁烯二酸二甲酯的总收率为91.0％.     

钯催化C-H乙酰氧基化反应

Pd催化的C—H官能化反应是目前有机合成方法学的一个重要研究热点.毫无疑问,这种温和又有选择性地转化方式广泛运用于化学各个领域.钯催化反应在近十年内得到了很大的发展,但是对于有机化学家来说仍然是一个挑战.综述了近十年来关于在C(sp2)—H和C(sp3)—H乙酰氧基化反应的研究进展及其应用,并提出了今后的研究重点和发展趋势.     

钯催化下芳基磺酸酯和芳基硅烷的Hiyama交叉偶联反应

钯催化下有机硅试剂和有机亲电试剂的Hiyama偶联反应是形成碳-碳键的重要方法之一．相较于有机锌、锡试剂和格氏试剂,有机硅试剂易于操作,对空气和水也较稳定,且毒性很低．另一方面,芳基磺酸酯作为交叉偶联反应中的亲电试剂正在受到很大关注．作为酚的衍生物,此类化合物廉价易得,性质稳定且易于操作．     

Grignard-type reactions with zerovalent nickel complexes

Summary Allyl esters react selectively at room temperature with aromatic aldehydes and Nio complexes in alcoholic solvents to form aryl-substituted secondary alcohols. In tetrahydrofuran at 70°, ketones and aliphatic aldehydes react satisfactorily to give tertiary and secondary alcohols respectively. Ligands able to promote oxidative addition exert a favourable influence provided they do not complex to the exclusion of the substrate.     

Grignard-type reactions with transition metals: alkylation of carbon compounds in protic solvents

Allylic halides react with reduced cobalt or nickel halides and with carbonyl compounds according to a pattern analogous to that of a Grignard reaction but with the difference that protic solvents can be used.     

Pd-catalyzed N-arylation of heteroarylamines

The palladium-catalyzed N-(hetero)arylation of a number of heteroarylamines including 2-aminopyridines, 2-aminothiazoles, and their analogues has been realized using Xantphos as the ligand. Weak bases such as Cs(2)CO(3), Na(2)CO(3), and K(3)PO(4) were used in most cases to allow for the introduction of functional groups. Choice of the base and solvent was critical for the success of these reactions. [reaction: see text]     

Highly efficient Grignard-type imine additions via C-H activation in water and under solvent-free conditions

A highly effective Cu-Ru catalyzed addition of terminal alkynes to imines via C-H activation has been achieved in water or under solvent-free conditions.     

Enantioselective Pd-catalyzed hydrogenation of enesulfonamides

Asymmetric hydrogenation of cyclic enesulfonamides affords chiral cyclic sulfonamides using Pd(OCOCF(3))(2)/diphosphine complexes as catalysts with up to 98% ee.     

Pd-catalyzed allylic alkylation of thioamides

This work describes the first Pd-catalyzed allylic alkylation of thioamides. Various thioamides were efficiently α-allylated in high yields and with excellent selectivity for monoallylation under mild reaction conditions. The process not only provides a facile method for the synthesis of functionalized thioamides, but also presents a useful transformation for synthetically important thioamides.     

An efficient of Grignard-type procedure for the preparation of gem-diallylated compound

An efficient and a new procedure for the conversion of various carboxylic acid derivatives into the corresponding gem-diallylated compound under mild reaction condition has been developed. The triallylaluminum mediated Grignard-type addition of carboxylic acid derivative was utilized as a key operation to affect the transformation. The procedure is operationally simple, giving good to excellent product yields for a broad range of substrates. The chemoselectivity and regioselectivity of triallylaluminum were also demonstrated.     

Grignard-type allylation of carbonyl compounds in methanol by the electrochemically recycled allyltin reagent.

An electrochemical allylation of aldehydes and ketones in methanol was achieved by the electroreductive regeneration of diallyltin reagent in the presence of a catalytic amount of tin, affording the corresponding homoallyl alcohols in 72 – 91% yields.     

Pd-catalyzed cross-coupling reactions of alkyl halides

Cross-coupling reactions have become indispensable tools for creating carbon-carbon (or heteroatom) bonds in organic synthesis. Like in other important transition metal catalyzed reactions, such as metathesis, addition, and polymerization, unsaturated compounds are usually employed as substrates for cross-coupling reactions. However during the past decade, a great deal of effort has been devoted to the use of alkyl halides as saturated compounds in cross-coupling reactions, which has resulted in significant progress in this undeveloped area by introducing new effective ligands. Many useful catalytic systems are now available for synthetic transformations based on C(sp(3))-C(sp(3)), C(sp(3))-C(sp(2)) and C(sp(3))-C(sp) bond formation as complementary methods to conventional C(sp(2))-C(sp(2)), C(sp(2))-C(sp) and C(sp)-C(sp) coupling. This tutorial review summarizes recent advances in cross-coupling reactions of alkyl halides and pseudohalides catalyzed by a palladium complex.     

Pd-catalyzed oxidative ortho-C-H borylation of arenes

The development of a Pd-catalyzed oxidative ortho-C-H borylation with N-arylbenzamides is reported. A modified dibenzylideneacetone (dba) ligand, a weak base, and a strong oxidant are critical for obtaining good yields. The reaction is tolerant of electron-deficient and electron-rich benzamides derived from readily available benzoic acids. The borylated products can be converted to various synthons via diverse transformations.