Green and efficient C–C bond cleavage/cyanoalkylation of quinoxalin-2(1H)-ones and other heteroarenes under visible light or sunlight irradiation is described. The reaction proceeds under mild conditions at room temperature without transition-metal catalysts and extra bases. Notably, the products enable facile transformations to various significant organic compounds.
<i>O</i>-Perfluoropyridin-4-yl Oximes: Iminyl Radical Precursors for Photo- or Thermal-Induced N–O Cleavage in C(sp<sup>2</sup>)–C(sp<sup>3</sup>) Bond Formation
作者:Peng-Ju Xia、Yuan-Zhuo Hu、Zhi-Peng Ye、Xu-Jie Li、Hao-Yue Xiang、Hua Yang
DOI:10.1021/acs.joc.9b03251
日期:2020.3.6
group was first installed onto cycloketone oximes as a new electrophore, which was proven to be efficient iminyl radicalprecursors under photocatalytic and thermal conditions. A range of O-perfluoropyridin-4-yl oximes were successfully utilized in C(sp2)-C(sp3) bond formations of quinoxalin-2(1H)-ones and alkenes, providing facile accesses to a range of functionalized alkylnitriles.
An efficient synthesis of cyanoalkylated heteroarenes via iron-catalyzed direct C–Hcyanoalkylation of heteroarenes has been developed. Structurally diverse cyanoalkyl motifs generated throughC–C bond cleavage of cyclobutanone oxime esters have been introduced into quinoxalin-2(1H)-ones, flavone, benzothiazoles, and caffeine in good to excellent yields. Remarkably, less-strained cyclopentanone and
Visible-light-driven cyanoalkylation of quinoxalinones using cyclobutanone oxime esters as the radical precursors
作者:Bin Zhao、Xianqiang Kong、Bo Xu
DOI:10.1016/j.tetlet.2019.06.059
日期:2019.8
We have developed a versatile visible-light-driven cyanoalkylation of quinoxalinones under mild conditions. First, the cyanoalkyl radicals are generated from readily available cyclobutanone oxime esters under blue light irradiation. Then the generated radicals react with heterocycles such as quinoxalinones to give the final cyanoalkylation products. The protocol tolerates a wide range of functional groups. Our cyanoalkylation protocol does not need cyanide-based reagents and also does not need external oxidants. (C) 2019 Elsevier Ltd. All rights reserved.