Kinetic resolution by copper-catalyzed azide–alkyne cycloaddition
摘要:
The use of chiral pybox ligands imparts enantioselectivity to the Cu-I-catalyzed azide-alkyne cycloaddition reaction, in the form of kinetic resolution of alpha-chiral azides and desymmetrization of gem-diazides. While levels of selectivity are modest, the results show unequivocally that the process benefits from ligand-accelerated catalysis. (c) 2005 Elsevier Ltd. All rights reserved.
Practical and regioselective amination of arenes using alkyl amines
作者:Alessandro Ruffoni、Fabio Juliá、Thomas D. Svejstrup、Alastair J. McMillan、James J. Douglas、Daniele Leonori
DOI:10.1038/s41557-019-0254-5
日期:2019.5
these molecules are assembled through the stepwise introduction of a reactivity handle in place of an aromatic C-H bond (that is, a nitro group, halogen or boronic acid) and a subsequent functionalization or cross-coupling. Here we show that aromaticamines can be constructed by direct reaction of arenes and alkyl amines using photocatalysis, without the need for pre-functionalization. The process
Cobalt-Catalyzed Alkyne Hydrosilylation and Sequential Vinylsilane Hydroboration with Markovnikov Selectivity
作者:Ziqing Zuo、Ji Yang、Zheng Huang
DOI:10.1002/anie.201605615
日期:2016.8.26
pyridinebis(oxazoline) cobalt complex is a very efficient precatalyst for the hydrosilylation of terminal alkynes with Ph2SiH2, providing α‐vinylsilanes with high (Markovnikov) regioselectivity and broad functional‐group tolerance. The vinylsilane products can be further converted into geminal borosilanes through Markovnikov hydroboration with pinacolborane and a bis(imino)pyridine cobalt catalyst.
The cobalt(II) complexes prepared with a series of enantiopure ligands (1-3) containing the bis(oxazolinyl)pyridine unit have been studied. The ligands form high spin octahedral complexes as shown by the X-ray crystal structure of the homochiral complex [Co(R,R-1)2](ClO4)2(CH3CN)3. The diastereoselectivity of complex formation has been studied: equimolar mixtures of RR and SS ligands show mixtures
已经研究了用一系列含有双(恶唑啉基)吡啶单元的对映体纯配体 (1-3) 制备的钴 (II) 配合物。配体形成高自旋八面体配合物,如同手性配合物 [Co(R,R-1)2](ClO4)2(CH3CN)3 的 X 射线晶体结构所示。已经研究了复合物形成的非对映选择性:RR 和 SS 配体的等摩尔混合物显示 2 和 3 的纯手性和异手性复合物的混合物,但苯基取代的配体 1 显示了异手性物种的排他性形成。这种选择性与配合物的结构和电子特性相关。
A Ce(OTf)<sub>3</sub>/PyBox catalyzed enantioselective Hosomi–Sakurai reaction of aldehydes with allyltrimethylsilane
作者:Song Zhao、Xulong Zhang、Yuwei Zhang、Huanhuan Yang、Yan Huang、Kui Zhang、Ting Du
DOI:10.1039/c5nj01488c
日期:——
An approach to the efficient synthesis of enantioselective homoallylic alcohols has been developed by the use of a catalytic amount of a cerium/PyBox complex.
通过使用少量铈/PyBox复合物催化,已经开发出一种高效合成对映选择性同烯丙基醇的方法。
Highly Chemo-, Regio-, and Stereoselective Cobalt-Catalyzed Markovnikov Hydrosilylation of Alkynes
作者:Jun Guo、Zhan Lu
DOI:10.1002/anie.201605501
日期:2016.8.26
A highly chemo‐, regio‐ and stereoselective cobalt‐catalyzed Markovnikov hydrosilylation of alkynes was developed. Various functionalized groups, such as halides, free alcohols, free aniline, ketones, esters, amides, and nitriles are tolerated, which may lead to further applications and late‐stage derivatizations. To date, this is the most efficient cobalt catalytic system (TOF=65 520 h−1; TOF=turnover
开发了高度化学,区域和立体选择性的钴催化炔烃的马尔科夫尼可夫氢化硅烷化反应。允许使用各种官能团,例如卤化物,游离醇,游离苯胺,酮,酯,酰胺和腈,这可能导致进一步的应用和后期衍生化。迄今为止,这是炔烃氢化硅烷化的最有效的钴催化系统(TOF = 65520 h -1; TOF =周转频率)。乙烯基硅烷与芳基碘化物的Hiyama-Denmark交叉偶联反应平稳进行,得到1,1-二芳烃。还描述了炔烃的独特的区域选择性可控的氢化硅烷化/硼氢化反应。