Regioselective bromination of fused heterocyclic N-oxides.
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 Ts(2)O/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.
Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States.
Sarah E
SE
Wengryniuk
Andreas
A
Weickgenannt
Christopher
C
Reiher
Neil A
NA
Strotman
Ke
K
Chen
Martin D
MD
Eastgate
Phil S
PS
Baran
D002384:Catalysis; D003497:Cyclic N-Oxides / Q000737:chemistry*; D054879:Halogenation; D006842:Hydrocarbons, Brominated / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism
D003497:Cyclic N-Oxides; D006842:Hydrocarbons, Brominated