Photoredox/Cobalt Dual Catalysis for Visible-Light-Mediated Alkene–Alkyne Coupling
作者:Pramod Rai、Kakoli Maji、Biplab Maji
DOI:10.1021/acs.orglett.9b01201
日期:2019.5.17
Dual photoredox transition-metal catalysis has recently emerged as a powerful tool for making synthetically challenging carbon–carbon bonds under milder reaction conditions. Herein, we report on the visible-light-mediated controlled generation of low-valent cobalt catalyst without the need for a metallic reductant. It enabled C–C bondformation via ene-yne coupling at roomtemperature. The generality
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。
Visible‐Light‐Driven Intermolecular Reductive Ene–Yne Coupling by Iridium/Cobalt Dual Catalysis for C(sp
<sup>3</sup>
)−C(sp
<sup>2</sup>
) Bond Formation
作者:María J. González、Bernhard Breit
DOI:10.1002/chem.201903708
日期:2019.12.10
A new methodology to form C(sp3 )-C(sp2 ) bonds by visible-light-driven intermolecular reductive ene-yne coupling has been successfully developed. The process relies on the ability of the Hantzsch ester to contribute in both SET and HAT processes through a unified cobalt and iridium catalytic system. This procedure avoids the use of stoichiometric amounts of reducing metallic reagents, which is translated
Copper‐Catalyzed Synthesis of Tetrasubstituted Alkenes via Regio‐ and
<i>anti</i>
‐Selective Addition of Silylboronates to Internal Alkynes
作者:Hirokazu Moniwa、Ryo Shintani
DOI:10.1002/chem.202100933
日期:2021.5.12
As a new and complementary method for the synthesis of structurally defined tetrasubstituted alkenes, a copper‐catalyzed regio‐ and anti‐selectiveaddition of silylboronates to unsymmetric internal alkynes has been developed. A variety of unactivated alkynes can be employed with high selectivity under simple and mild conditions, and the resulting products have been further functionalized by utilizing
Pd‐catalyzed bromoallylation of unsymmetricalalkynes represents a simple approach towards functionalized olefins. The regioselectivity of this process is influenced by the direction of the polarization of the triple bond as well as by directingeffects of a coordinating group in the pendant chain.