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Air-Stable Precatalysts for Amination

By: Josephine Nakhla, Chemfiles Volume 10 Article 3

C–N bond forming cross-couplings typically require a palladium source along with the associated ligands. Most Pd(0) sources are not air-stable, while the commonly employed air-stable Pd(0) source, Pd2(dba)3 contains associated ligands which could impede the reaction. Stable Pd(II) precursors require reduction under the reaction conditions. In either case, a ligand must be added to the reaction in order to lead to the active Pd-species. Buchwald and coworkers recently reported the use of highly-active yet air- and moisture-stable precatalysts, which, under the standard reaction conditions, form the active monoligated Pd-species. These precatalysts (704954, 704946, 707589, 708739) are exceptionally efficient even under challenging conditions, such as coupling electron-poor anilines with deactivated aryl chlorides. The catalyst precursors also offer other advantages including low catalyst loadings and short reaction times.


Scheme 2. Buchwald precatalysts in N-arylations of electron-poor amines with electron-rich aryl chlorides

Scheme 2. Buchwald precatalysts in N-arylations of electron-poor amines with electron-rich aryl chlorides (704954) (707589)

Scheme 3. Buchwald precatalysts in N-arylations with low catalyst loadings

Scheme 3. Buchwald precatalysts in N-arylations with low catalyst loadings (704954)

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Materials

     

References

  1. Biscoe, M. R. et al. J. Am. Chem. Soc. 2008, 130, 6686.

For more information on our Buchwald catalyst and ligand portfolio, visit aldrich.com/buchwald

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