Regioselective Bromination of Fused Heterocyclic N‑Oxides
journal contributionposted on 15.02.2013 by Sarah E. Wengryniuk, Andreas Weickgenannt, Christopher Reiher, Neil A. Strotman, Ke Chen, Martin D. Eastgate, Phil S. Baran
Any type of content formally published in an academic journal, usually following a peer-review process.
A mild method for the regioselective C2-bromination of fused azine N-oxides is presented, employing tosic anhydride as the activator and tetra-n-butylammonium bromide as the nucleophilic bromide source. The C2-brominated compounds are produced in moderate to excellent yields and with excellent regioselectivity in most cases. The potential extension of this method to other halogens, effecting C2-chlorination with Ts2O/TBACl is also presented. Finally, this method could be incorporated into a viable one-pot oxidation/bromination process, using methyltrioxorhenium/urea hydropgen peroxide as the oxidant.