N-Acyloxyphthalimides as Nitrogen Radical Precursors in the Visible Light Photocatalyzed Room Temperature C–H Amination of Arenes and Heteroarenes
摘要:
This paper reports a room temperature visible light photocatalyzed method for the C-H amination of arenes and heteroarenes. A key enabling advance in this work is the design of N-acyloxyphthalimides as precursors to nitrogen-based radical intermediates for these transformations. A broad substrate scope is presented, including the selective meta-amination of pyridine derivatives. A radical aromatic substitution mechanism is proposed.
作者:Min Zheng、Ke Gao、Haitao Qin、Guigen Li、Hongjian Lu
DOI:10.1002/anie.202108617
日期:2021.10.11
enantiopurity of divergent products. Both reactions proceed efficiently with catalyst loading as low as 0.2 mol % and can be performed on a gram scale without loss of chemoselectivity or enantioselectivity. Chemodivergent asymmetric 1,5-aminocyanation or 1,5-oxocyanation of vinylcyclopropane can also be realized by this protocol. Mechanistic investigations involving electron paramagnetic resonance (EPR)
The present strategy provides ways to introduce functionalities such as N-acyloxyphthalimide or -succinimide specifically to terminal glycine segment of peptides. Herein, mild conditions and high functional-group tolerance allow the preparation of non-natural α-aminoacids and modification of corresponding peptides in this way.
Direct C(sp<sup>2</sup>)–H amination of aryl aldehyde-derived hydrazones via visible light promoted photoredox catalysis
作者:Xin Zhu、Zhi He、Qiu-Yan Li、Xiao-Jun Wang
DOI:10.1039/c7ra01229b
日期:——
An unprecedented visible-light-induced direct C(sp2)–Hamination of aryl aldehyde-derived hydrazones was developed by using N-acyloxyphthalimides as nitrogen-radical precursors. This reaction represents a new way to substituted hydrazones with amination of carbon–nitrogen π bonds. A radical C–H amination mechanism is proposed.
Visible-Light-Driven C–H Imidation of Arenes and Heteroarenes by a Phosphonium Ylide Organophotoredox Catalyst: Application to C–H Functionalization of Alkenes
作者:Yasunori Toda、Toya Kobayashi、Fumiya Hirai、Takamichi Yano、Makoto Oikawa、Kimiya Sukegawa、Masahiro Shimizu、Fuyuki Ito、Hiroyuki Suga
DOI:10.1021/acs.joc.3c00988
日期:2023.7.7
Phosphonium ylide catalysis through an oxidative quenching cycle has been developed for visible-light-driven C–H imidation of arenes and heteroarenes. The present protocol could be applied not only to trihalomethylative lactonization reactions involving trifluoromethyl, trichloromethyl, and tribromomethyl radicals but also to the first example of an organophotoredox-catalyzed imidative lactonization