Journal article
Manganese-Catalyzed Cross-Coupling of Aryl Halides and Grignard Reagents by a Radical Mechanism : Manganese-Catalyzed Cross-Coupling of Aryl Halides and Grignard Reagents by a Radical Mechanism
The substrate scope and the mechanism have been investigated for the MnCl2-catalyzed cross-coupling reaction between aryl halides and Grignard reagents. The transformation proceeds rapidly and in good yield when the aryl halide component is an aryl chloride containing a cyano or an ester group in the para position or a cyano group in the ortho position.
A range of other substituents gave no conversion of the aryl halide or led to the formation of side products. A broader scope was observed for the Grignard reagents, where a variety of alkyl- and arylmagnesium chlorides participated in the coupling. Two radical-clock experiments were carried out, and in both cases an intermediate aryl radical was successfully trapped.
The cross-coupling reaction is therefore believed to proceed by an SRN1 mechanism, with a triorganomanganate complex serving as the most likely nucleophile and single-electron donor. Other mechanistic scenarios were excluded based on the substrate scope of the aryl halide.
Language: | English |
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Year: | 2017 |
Pages: | 4758-4764 |
ISSN: | 10990690 and 1434193x |
Types: | Journal article |
DOI: | 10.1002/ejoc.201700981 |
ORCIDs: | Madsen, Robert |
Cross-coupling Earth-abundant metals Grignard reagents Manganese Radical reactions Reaction mechanisms