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Regioselective Bromine/Magnesium Exchange for the Selective Functionalization of Polyhalogenated Arenes and Heterocycles.

ABSTRACT: Using the bimetallic combination sBu₂ 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.

SUBMITTER: Desaintjean A

PROVIDER: S-EPMC7839478 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature

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Regioselective Bromine/Magnesium Exchange for the Selective Functionalization of Polyhalogenated Arenes and Heterocycles.

Desaintjean Alexandre A Haupt Tobias T Bole Leonie J LJ Judge Neil R NR Hevia Eva E Knochel Paul P

Angewandte Chemie (International ed. in English) 20201119 3

Using the bimetallic combination sBu<sub>2</sub> 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 ...[more]

PMID: 33079466

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