Regioselective bromination of fused heterocyclic N-oxides.
Regioselective bromination of fused heterocyclic N-oxides.
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DOI：
10.1021/ol3034675
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发表时间：
2013-01
期刊：
影响因子：
5.2
通讯作者：
Sarah E. Wengryniuk;A. Weickgenannt;Christopher A. Reiher;N. Strotman;K. Chen;Martin D. Eastgate;P. Baran
中科院分区：
文献类型：
--
作者：
Sarah E. Wengryniuk;A. Weickgenannt;Christopher A. Reiher;N. Strotman;K. Chen;Martin D. Eastgate;P. Baran
以对甲苯磺酸酐为活化剂，溴化四正丁基铵为亲核溴源，研究了稠合吖嗪N-氧化物的C2-溴代反应。在大多数情况下，C2-溴化化合物以中等至优异的产率和优异的区域选择性生产。该方法还可推广到其它卤素的氯化反应中，如Ts（2）O/TBACl的C2-氯化反应。最后，这种方法可以被纳入一个可行的一锅氧化/溴化过程中，使用甲基三氧化铼/尿素过氧化氢作为氧化剂。
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.