Cationic Ruthenium Catalysts for Alkyne Annulations with Oximes by C–H/N–O Functionalizations
摘要:
Cationic ruthenium(II) complexes enabled efficient redox-neutral annulations of alkynes with readily available oximes. The catalytic dehydrative C-H/N-O bond functionalization proved to be broadly applicable and was shown to proceed through a reversible cyclometalation.
Dynamic multiligand catalysis: A polar to radical crossover strategy expands alkyne carboboration to unactivated secondary alkyl halides
作者:Shin-Ho Kim-Lee、Pablo Mauleón、Ramón Gómez Arrayás、Juan C. Carretero
DOI:10.1016/j.chempr.2021.06.002
日期:2021.8
triggers cooperative polar/radical pathways in a single catalytic cycle. This strategy has been applied to address a restricting limitation inherent to Cu-catalyzed B2pin2-carboboration of alkynes—the very low reactivity of the intermediate vinyl-Cu(I) species, which renders conventional methods ineffective with alkyl electrophiles other than simple primary halides. The crossover strategy enabled by
我们描述了基于前所未有的动态多配体配位池的 Cu 催化的双重策略,该池在单个催化循环中触发合作的极性/自由基途径。该策略已被应用于解决 Cu 催化的 B 2 pin 2固有的限制性限制-炔烃的碳硼化——中间体乙烯基-Cu(I) 物质的反应性非常低,这使得传统方法对烷基亲电试剂无效,而不是简单的伯卤化物。通过有机金属中间体中的配体交换实现的交叉策略克服了这一反应性问题,将碳硼化的范围扩大到未活化的仲烷基卤化物,并开辟了获得立体定义的四取代乙烯基硼酸酯的新途径。该方法具有区域选择性和立体选择性,显示出优异的官能团耐受性,并允许在任一反应伙伴处掺入复杂的碳环和杂环片段。
Fluorobenziodoxole−BF
<sub>3</sub>
Reagent for Iodo(III)etherification of Alkynes in Ethereal Solvent
reaction tolerates a variety of functionalized internal and terminal alkynes to afford trans‐β‐alkoxyvinylbenziodoxoles, which represent versatile precursors to stereochemically well‐defined multisubstituted vinyl ethers. The reaction is proposed to involve cleavage of the I−F bond of FBX by BF3, followed by electrophilic activation of the alkyne by the resulting cationic IIII species that triggers the
Ambient arylmagnesiation of alkynes catalysed by ligandless nickel(ii)
作者:Fei Xue、Jin Zhao、T. S. Andy Hor
DOI:10.1039/c3cc45202f
日期:——
A simple and efficient catalytic arylmagnesiation of diarylacetylenes and aryl(alkyl)acetylenes is accomplished by NiCl2·6H2O at r.t. in the absence of stabilising ligands. The corresponding tetra-substituted alkenes can be obtained in good yields by subsequent treatment with different electrophiles.
selective [2 + 2]-cycloaddition and dearomatizing cascade reaction of aryl alkynes with acrylates with high chemo- and stereoselectivity. The obtained cyclobutene could be easily converted into cyclobutane as well as synthetically useful 1,4- and 1,5-diketones with high chemo- and stereoselectivity. On the basis of mechanistic studies, plausible reaction mechanisms were proposed for both the [2 + 2]-cycloaddition
Versatile telluracycle synthesis via the sequential electrophilic telluration of C(sp<sup>2</sup>)–Zn and C(sp<sup>2</sup>)–H bonds
作者:Bin Wu、Melvina Melvina、Xiangyang Wu、Edwin Kok Lee Yeow、Naohiko Yoshikai
DOI:10.1039/c7sc01162h
日期:——
We report herein a new approach for the synthesis of tellurium-bridged aromatic compounds based on the sequential electrophilic telluration of C(sp2)–Zn and C(sp2)–Hbonds with tellurium(IV) chlorides. A combination of transition metal-catalyzed (migratory) arylmetalation of alkynes and sequential telluration allows for the expedient construction of a library of functionalized benzo[b]tellurophenes
我们在此报告了一种新的合成碲桥接芳族化合物的新方法,该方法基于C(sp 2)-Zn和C(sp 2)-H键与碲(IV)氯化物的顺序亲电碲化。炔烃的过渡金属催化(迁移)芳基金属化和连续碲化相结合,可以方便地构建功能化的苯并[ b ]碲二苯酚文库。此外,可以容易地从相应的2-碘杂双联芳基合成各种杂芳基稠合的苯并二氮杂苯并与其他新颖的碲嵌入的多环芳族化合物。