Gao Shuang, Bethel Travis K, Kakeshpour Tayeb, Hubbell Grace E, Jackson James E, Tepe Jetze J
Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States.
J Org Chem. 2018 Aug 17;83(16):9250-9255. doi: 10.1021/acs.joc.8b01251. Epub 2018 Jul 17.
Electrophilic bromination of pyrroles bearing carbonyl substituents at C-2 typically results in a mixture of the 4- and 5-brominated species, generally favoring the 4-position. Herein, we describe a substrate-controlled regioselective bromination in which tetra-butyl ammonium tribromide (TBABr) reacts with pyrrole-2-carboxamide substrates to yield the 5-brominated species as the predominant (up to >10:1) product.
在C-2位带有羰基取代基的吡咯的亲电溴化反应通常会生成4-溴代和5-溴代产物的混合物，一般以4-位产物为主。在此，我们描述了一种底物控制的区域选择性溴化反应，其中三溴化四丁基铵（TBABr）与吡咯-2-甲酰胺底物反应，以5-溴代产物作为主要产物（比例高达>10:1）生成。
