Regioselective Bromine/Magnesium Exchange for the Selective Functionalization of Polyhalogenated Arenes and Heterocycles
作者:Alexandre Desaintjean、Tobias Haupt、Leonie J. Bole、Neil R. Judge、Eva Hevia、Paul Knochel
DOI:10.1002/anie.202012496
日期:2021.1.18
toluene enables efficient and regioselective Br/Mg exchanges with various dibromo‐arenes and ‐heteroarenes under mild reaction conditions and provides bromo‐substituted magnesium reagents. Assessing the role of Lewis donor additives in these reactions revealed that N,N,N′,N′′,N′′‐pentamethyldiethylenetriamine (PMDTA) finely tunes the regioselectivity of the Br/Mg exchange on dibromo‐pyridines and quinolines
使用双金属组合SBU 2在甲苯Mg⋅2LIOR(R = 2-乙基己基)使温和的反应条件下与各种二溴芳烃和-heteroarenes高效和区域选择性比Br / Mg的交流,并提供溴代镁试剂。评估Lewis供体添加剂在这些反应中的作用表明,N,N,N',N'',N''-五甲基二亚乙基三胺(PMDTA)可以很好地调节Br / Mg交换在二溴吡啶和喹啉上的区域选择性。结合光谱学和X射线晶体学研究,已经实现了完成这些转变的有机金属中间体的混合Li / Mg组成的光。这些系统可与多种亲电试剂有效反应,包括烯丙基溴,酮,醛和Weinreb酰胺,收率很高。