Solvent-controlled stereodivergent synthesis of E-and Z-enamines via metal-free formal C(sp^(2))-H amination ofα-substituted styrenes  

作　　者：Dangui Wang Jinbei Yao Wentao Zhang Shuyue Zhang Huaibin Yu Laihu Peng Weijun Yao Zhifeng Dai Guojiao Wu Fangrui Zhong 

机构地区：[1]School of Pharmacy,Weifang Medical University,Weifang 261053,China [2]Hubei Key Laboratory of Bioinorganic Chemistry&Materia Medica,School of Chemistry and Chemical Engineering,Huazhong University of Science and Technology(HUST),Wuhan 430074,China [3]Zhejiang Sci-Tech University,Hangzhou 310018,China

出　　处：《Green Synthesis and Catalysis》2024年第4期324-328,共5页绿色合成与催化（英文）

基　　金：supported by the National Natural Science Foundation of China(No.22001085);Shandong Provincial Natural Science Foundation(No.ZR2021QB148);Fundamental Research Funds for the Central Universities(No.HUST:2023JCYJ001);Research Institute of Zhejiang Sci-Tech University in Longgang(No.LGYJY2021013)for financial support。

摘　　要：C(sp^(2))-H amination represents an attractive approach for the synthesis of enamines,which is intrinsically associated with the challenge of controlling of stereochemistry and primarily relying on transition-metal catalysis.Herein,a metal-free C(sp^(2))-H amination ofα-substituted styrenes has been achieved,leading to stereodivergent formation of both E-and Z-enamines in 50%–97%yield under mild conditions by using PhI(OAc)_(2) as a green oxidant and ortho-phenylenediamines as nitrogen source.Interestingly,the Z/E selectivity can be controlled readily by switching the reaction medium.E-isomers were formed preferentially in THF,whereas n-hexane favored the formation of Z-isomers.Preliminary mechanistic studies suggested that in situ formed ortho-benzoquinone diimides are the key intermediates,and there is a correlation between solvent polarity and stereoselectivity.This study enriches the chemical repertoire of ortho-benzoquinone diimides particularly with respect to sustainable amination.

关 键 词：ENAMINES Stereodivergent synthesis METAL-FREE Hypervalent iodine C(sp^(2))-H aminatio 

分 类 号：O62[理学—有机化学]