10.1002/chem.201703191
Chemistry - A European Journal
COMMUNICATION
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Scheme 6. (a) Computed ΔG343.15 for manganese-catalyzed C−H methylation
with dispersion corrections. (b) Catalytic cycle calculated energetics (kcal mol-1)
with (blue) and without dispersion correction (red).
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same time providing access to substituted benzoic acids 7
(Scheme 7).
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Scheme 7. Removal of reusable TAM group to deliver benzoic acids.
In summary, we have reported on the first manganese-catalyzed
C–H activation with organic halides. The unprecedented low-
valent manganese-catalyzed C–H alkylation occurred under
zinc-free reaction conditions in the absence of any expensive
phosphine ligands, providing versatile access to C–H-alkylated
benzamides by assistance of the removable TAM group.
Mechanistic studies provided strong support for
a rate-
determining C–H activation, which also set the stage for
transformative oxidative C–H methylations.
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Acknowledgements
[7]
[8]
Generous by the CSC (fellowship to Z.S.), the Alexander von
Humboldt Foundation (fellowship to G.C.), the DFG (SPP 1807),
and the European Research Council under the Seventh
Framework
Program
of
the
European
Community
(FP720072013; ERC Grant Agreement No. 307535) is gratefully
acknowledged.
Keywords: C–H activation
• alkylation • manganese •
mechanism • selectivity
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