Solvent-controlled switch between aziridination and Beckmann-type amidation of chalcones with hydroxylammonium salts
Yao Ma1, Zhenjie Qi2, Yafeng Liu3
1Key Laboratory of Protection, Development and Utilization of Medicinal Resources in Liupanshan Area, Ministry of Education, Peptide & Protein Drug Research Center, School of Pharmacy, Ningxia Medical University Yinchuan 750004 China anzy@nxmu.edu.cn gxl2018666@163.com.
None:
Herein, we disclose a solvent-controlled switch between aziridination and Beckmann-type amidation of chalcones using MsONH3OTf as a common hydroxylammonium reagent. Specifically, the reaction in TFE delivers NH-aziridine derivatives via direct aziridination, whereas switching the solvent to THF promotes a Beckmann rearrangement to afford α,β-unsaturated amides. The solvent-dependent selectivity is supported by control experiments, HRMS detection of a hydroxylamine-derived intermediate, and the isolation of a bicyclic O-sulfonyl oxime, which is interpreted as a trapped intermediate-like species in the Beckmann-type pathway.
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