R 4 NHal/NOHSO 4: A Usable System for Halogenation of Isoxazoles, Pyrazoles, and Beyond

J Org Chem. 2021 Jan 1;86(1):322-332. doi: 10.1021/acs.joc.0c02106. Epub 2020 Dec 21.


A new convenient and versatile halogenating system (R4NHal/NOHSO4), giving straightforward and general access to halogenated 3,5-diaryl- and alkylarylisoxazoles, pyrazoles and electron-rich benzenes from the corresponding scaffolds, is suggested. The method provides excellent regioselectivity, scalability to the gram scale, and a broad scope for both aromatics and halogens. A three-step, one-pot reaction protocol was developed, and a series of 3,5-diaryl-4-haloisoxazoles has been efficiently synthesized from 1,2-diarylcyclopropanes under suggested nitrosating-halogenating conditions.

Publication types

  • Research Support, Non-U.S. Gov't