Photochemical C–F Activation Enables Defluorinative Alkylation of Trifluoroacetates and -Acetamides
作者:Mark W. Campbell、Viktor C. Polites、Shivani Patel、Juliette E. Lipson、Jadab Majhi、Gary A. Molander
DOI:10.1021/jacs.1c11059
日期:2021.12.1
commodity feedstock: ethyl trifluoroacetate. A novel mechanistic approach was identified using our previously developed diaryl ketone HAT catalyst to enable the hydroalkylation of a diverse suite of alkenes. Furthermore, electrochemical studies revealed that more challenging radical precursors, namely trifluoroacetamides, could also be functionalized via synergistic Lewis acid/photochemical activation
尽管宝石-二氟亚甲基具有诱人的结构、物理和生化特性,但将其安装到有机结构中仍然是一项艰巨的合成挑战。一种非常有效的逆合成方法是将来自三氟甲基的单个 C-F 键功能化。这一系列攻击的最新进展使三氟甲基芳烃的 C-F 活化成为可能,但将可访问的基序限制为仅苄基宝石-二氟化支架。相比之下,三氟乙酸盐的 C-F 活化将使它们能够用作双功能宝石-二氟亚甲基合成子。在此,我们报告了一种光化学介导的商品原料脱氟烷基化方法:三氟乙酸乙酯。使用我们之前开发的二芳基酮 HAT 催化剂确定了一种新的机制方法,以实现多种烯烃的加氢烷基化。此外,电化学研究表明,更具挑战性的自由基前体,即三氟乙酰胺,也可以通过协同路易斯酸/光化学活化进行功能化。最后,该方法为 FDA 批准的药物化合物的新型宝石-二氟类似物提供了一种简洁的合成方法。
Nickel-Catalyzed <i>anti</i>-Markovnikov Hydrodifluoroalkylation of Unactivated Alkenes
An efficient Ni-catalyzed hydrodifluoroalkylation of unactivated alkenes with bromodifluoroacetate by using PhSiH3 as hydride source was developed. The transformation affords aliphatic difluorides with anti-Markovnikov regioselectivity. A wide range of highly remote alkenes, simple alkenes, drug molecules, commercially available CF2 precursors, and even nonfluorinated substrates are competent in this
A mild, versatile and efficient method for the regioselective hydrodifluoromethylation of unactivated alkenes has been developed. This Ag-mediated Csp(3)-CF2 bond forming reaction provides easy access to a variety of vicinal alpha-difluoroacetate-containing alkanes.
Arenethiolate as a Dual Function Catalyst for Photocatalytic Defluoroalkylation and Hydrodefluorination of Trifluoromethyls
作者:Can Liu、Kang Li、Rui Shang
DOI:10.1021/acscatal.2c00592
日期:2022.4.1
a photocatalyst in photoredoxcatalysis, but we report herein that an arene thiolate with an appropriate substituent can be photoactivated under visible light to function as both a strongly reducing electron-donating redox catalyst and a HAT catalyst to enable catalytic C–F activation of trifluoromethyl substrates for selective hydrodefluorination and coupling with various alkenes in the presence of
已知硫醇在光氧化还原催化中充当与光催化剂协同作用的氢原子转移催化剂,但我们在本文中报道了具有适当取代基的芳烃硫醇盐可以在可见光下光活化,从而起到强还原性给电子氧化还原的作用催化剂和 HAT 催化剂能够催化 C-F 活化三氟甲基底物,用于选择性加氢脱氟并在甲酸盐存在下与各种烯烃偶联。这些反应证明了硫醇盐作为双功能光催化剂的前景广阔。该方法的合成效用通过适用的三氟甲基底物的广泛范围来证明,包括三氟甲基化(杂)芳烃、三氟乙酸盐和三氟乙酰胺,它们表现出高水平的化学选择性。
Radical Addition-Triggered Remote Migratory Isomerization of Unactivated Alkenes to Difluoromethylene-Containing Alkenes Enabled by Bimetallic Catalysis
A fascinating alkeneremote migratory isomerization engendered by carbon radical addition to C═C bond in alkenes via bimetalliccatalysis has been disclosed. A diverse array of alkenes bearing distantly incorporated the difluoromethylene (RCF2R′) functionality have been expediently obtained. The retainment of C═C bonds in products could serve as an useful synthetic platform furnishing otherwise difficult