Transition-metal-catalyzed cross-coupling reactions between naturally abundant sp3-hybridized carbon centers facilitate access to diverse molecules with complex three-dimensional structures. Organometallic compounds are among one of the most powerful reagents that are broadly used in carbon–carbon bondformations. Although sp2-hybridized organometallic compounds are widely employed in cross-couplings, sp3-hybridized
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。
Ligand‐Controlled Regiodivergent Hydroalkylation of Pyrrolines
作者:Deyun Qian、Xile Hu
DOI:10.1002/anie.201912629
日期:2019.12.16
Nickel hydride (NiH) catalyzed hydrocarbonation has emerged as an efficient approach to construct new C-C bonds containing at least one C(sp3 ) center. However, the regioselectivity of this reaction is by far dictated by substrates. Described here is a strategy to achieve two different regioselectivites of hydroalkylation of the same substrates by using ligand control. This strategy enables the first
From Alkyl Halides to Ketones: Nickel‐Catalyzed Reductive Carbonylation Utilizing Ethyl Chloroformate as the Carbonyl Source
作者:Renyi Shi、Xile Hu
DOI:10.1002/anie.201903330
日期:2019.5.27
remains in high demand. Described here is a nickel‐catalyzed three‐component reductive carbonylation method for the synthesis of dialkyl ketones. A wide range of both symmetric and asymmetric dialkyl ketones can be accessed from alkyl halides and a safe CO source, ethyl chloroformate. The approach offers complementary substrate scope to existing carbonylation methods while avoiding the use of either toxic
Mild and Phosphine-Free Iron-Catalyzed Cross-Coupling of Nonactivated Secondary Alkyl Halides with Alkynyl Grignard Reagents
作者:Chi Wai Cheung、Peng Ren、Xile Hu
DOI:10.1021/ol501087m
日期:2014.5.2
cross-coupling of nonactivated secondary alkylbromides and iodides with alkynyl Grignardreagents at room temperature has been developed. A wide range of secondary alkyl halides and terminal alkynes are tolerated to afford the substituted alkynes in good yields. A slight modification of the reaction protocol also allows for cross-coupling with a variety of primary alkyl halides.