Desaintjean Alexandre, Haupt Tobias, Bole Leonie J, Judge Neil R, Hevia Eva, Knochel Paul
Ludwig-Maximilians-Universität München, Department Chemie, Butenandtstrasse 5-13, Haus F, 81377, München, Germany.
Department für Chemie und Biochemie, Universität Bern, 3012, Bern, Switzerland.
Angew Chem Int Ed Engl. 2021 Jan 18;60(3):1513-1518. doi: 10.1002/anie.202012496. Epub 2020 Nov 19.
Using the bimetallic combination sBu Mg⋅2 LiOR (R=2-ethylhexyl) in 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. Combining spectroscopic with X-ray crystallographic studies, light has been shed on the mixed Li/Mg constitution of the organometallic intermediates accomplishing these transformations. These systems reacted effectively with a broad range of electrophiles, including allyl bromides, ketones, aldehydes, and Weinreb amides in good yields.
在甲苯中使用双金属组合sBuMg⋅2 LiOR（R = 2-乙基己基）能够在温和的反应条件下与各种二溴芳烃和二溴杂芳烃进行高效且区域选择性的Br/Mg交换，并提供溴代镁试剂。评估路易斯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）可精细调节二溴吡啶和喹啉上Br/Mg交换的区域选择性。通过光谱学与X射线晶体学研究相结合，揭示了实现这些转化的有机金属中间体的混合Li/Mg组成。这些体系能与多种亲电试剂有效反应，包括烯丙基溴、酮、醛和Weinreb酰胺，产率良好。
