Rational catalysis design on the basis of mechanistic understanding: highly efficient Pd-catalyzed cyanation of aryl bromides with NaCN in recyclable solvents.

Rational catalysis design on the basis of a detailed mechanistic understanding has been used to successfully develop the first efficient general Pd-catalyzed aromatic cyanation reaction under the highly sought after practicable conditions: (i) MCN (M = Na or K) as a cyanide source; (ii) low-boiling recyclable solvents; and (iii) minimal quantities of inexpensive, nontoxic promoters. The developed catalytic reaction converts aromatic bromides to the corresponding nitriles in 88-99% isolated yield with NaCN and 0.5-1.0 mol % of a t-Bu(3)P-monoligated Pd catalyst in MeCN-THF within 2 h at 70 °C. The process exhibits high functional group tolerance.