Copper‐Catalyzed Radical/Radical CH/PH Cross‐Coupling: α‐Phosphorylation of Aryl Ketone O‐Acetyloximes |
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Authors: | Jie Ke Yuliang Tang Hong Yi Yali Li Yongde Cheng Chao Liu Prof. Aiwen Lei |
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Affiliation: | 1. College of Chemistry and Molecular Sciences, The Institute for Advanced Studies (IAS), Wuhan University, Wuhan, Hubei 430072 (P.R. China) http://aiwenlei.whu.edu.cn/Main_Website/;2. Key Laboratory for Organic Electronics and Information Display and Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing, 210023 (P.R. China);3. State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, 730000 Lanzhou (P.R. China) |
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Abstract: | The selective radical/radical cross‐coupling of two different organic radicals is a great challenge due to the inherent activity of radicals. In this paper, a copper‐catalyzed radical/radical C? H/P? H cross‐coupling has been developed. It provides a radical/radical cross‐coupling in a selective manner. This work offers a simple way toward β‐ketophosphonates by oxidative coupling of aryl ketone o‐acetyloximes with phosphine oxides using CuCl as catalyst and PCy3 as ligand in dioxane under N2 atmosphere at 130 °C for 5 h, and yields ranging from 47 % to 86 %. The preliminary mechanistic studies by electron paramagnetic resonance (EPR) showed that, 1) the reduction of ketone o‐acetyloximes generates iminium radicals, which could isomerize to α‐sp3‐carbon radical species; 2) phosphorus radicals were generated from the oxidation of phosphine oxides. Various aryl ketone o‐acetyloximes and phosphine oxides were suitable for this transformation. |
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Keywords: | C(sp3) P bonds copper catalysis oxidative coupling radical/radical cross‐coupling β ‐ketophosphonates |
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