Buchwald palladium precatalysts

Palladium based catalysis is the most used tool to perform the formation of C-C, C-O and C-N. There are many sources of palladium such as PdOAc₂, PdCl₂ or Pd₂dba₃. However the related methods do not always allow sufficient conversion.

Palladium precatalysts is an efficient solution to generate in-situ the L_nPd(0) needed for the reaction. These precatalysts are generally air and moisture stable.

The first palladacycle precatalyst has been reported by Herman and Beller in 1995¹. Since then Buchwald laboratories has developed several types of palladium.

The first generation of Buchwald palladium precatalysts are phenethylamine derivatives. In presence of a base the LPd(0) can be generated in-situ.

 

The second generation of Buchwald palladium precatalysts are 2-aminobiphenyl derivatives. These precatalysts can be activated at room temperature.

The third generation of Buchwald palladium precatalysts are methylsulfonate salt of 2-aminobiphenyl derivatives. These precatalysts are compatible with bulky ligands and show longer stability in solution.

The fourth generation of Buchwald palladium precatalysts are methylsulfonate salt of 2-methylaminobiphenyl derivatives. These precatalysts are compatible with bulky ligands and show longer stability in solution.

 

 

1 Herman,W.A.; Beller,M. Angew. Chem. Int. Ed., 1995, 34, 1844-1848.