Water in N-Heterocyclic Carbene-Assisted Catalysis

Palladium has a very rich organometallic repertoire, and its high functional group tolerance makes it an attractive metal to study catalysis in water. Several arylboronic acids and aryl iodides or bromides were investigated, including substrates with electron-donating and electron-withdrawing groups. A control reaction with sodium hydroxide and methanol gave comparable results, supporting this theory; unfortunately other organic bases, such as sodium ethoxide or potassium tert-butoxide, were not tested to support this theory. Increased complex solubility in water may be achieved by attaching charged groups to the NHC ligand.