A novel Ni/photoredox-catalyzed acylation of aliphatic substrates, including simple alkanes and dialkyl ethers, has been developed. The method combines C–N bond activation of amides with a radical relay mechanism involving hydrogen-atom transfer. The protocol is operationally simple, employs bench-stable N-acyl imides as acyl-transfer reagents, and permits facile access to alkyl ketones under very
Direct coupling of ethers and acylhalides was promoted by a binary catalytic system comprising an Ir-based photocatalyst and a Ni complex under blue-light irradiation. Photocatalysts with high triplet energy directed the catalysis, and the reaction likely proceeded by triplet–triplet energy transfer from the excited photocatalysts. Chlorine radicals generated from an excited Ni complex bearing a Ni–Cl
Photoinduced Acylations Via Azolium-Promoted Intermolecular Hydrogen Atom Transfer
作者:Joshua L. Zhu、Cullen R. Schull、Anthony T. Tam、Ángel Rentería-Gómez、Achyut Ranjan Gogoi、Osvaldo Gutierrez、Karl A. Scheidt
DOI:10.1021/jacs.2c12845
日期:2023.1.25
Photoinduced hydrogenatomtransfer (HAT) has been developed as a powerful tool to generate synthetically valuable radical species. The direct photoexcitation of ketones has been known to promote HAT or to generate acyl radicals through Norrish-type pathways, but these modalities remain severely limited by radical side reactions. We report herein a catalyst- and transition metal-free method for the
光致氢原子转移 (HAT) 已被开发为生成具有合成价值的自由基物种的强大工具。已知酮的直接光激发可促进 HAT 或通过 Norrish 型途径产生酰基自由基,但这些方式仍然受到自由基副反应的严重限制。我们在此报告了一种无催化剂和过渡金属的 C-H 键酰化方法,该方法利用了稳定、可分离的酰基唑鎓物种的独特性质。具体而言,酰基唑盐显示在 LED 照射下会发生分子间和区域选择性 HAT,一系列底物带有活性 C-H 键,随后形成 C-C 键以提供酮。
DECARBOXYLATIVE CROSS-COUPLING AND APPLICATIONS THEREOF
申请人:THE TRUSTEES OF PRINCETON UNIVERSITY
公开号:US20200148668A1
公开(公告)日:2020-05-14
Methods described herein enable the production of numerous molecular species through decarboxylative cross-coupling via use of photoredox and transition metal catalysts. For example, methods described herein enable the production of numerous molecular species through decarboxylative cross-coupling via use of photoredox and transition metal catalysts. A method described herein, in some embodiments, comprises providing a reaction mixture including a photoredox catalyst, a transition metal catalyst, a coupling partner and a substrate having a carboxyl group. The reaction mixture is irradiated with a radiation source resulting in cross-coupling of the substrate and coupling partner via a mechanism including decarboxylation, wherein the coupling partner is selected from the group consisting of a substituted aromatic compound and a substituted aliphatic compound.