鈴木・宮浦カップリング
The ligand plays an important role in the Suzuki reaction. Typically, the phosphine ligand is used in the Suzuki reaction. Phosphine ligand increases the electron density at the metal center of the complex and therefore helps in the oxidative addition step. In addition, the bulkiness of substitution of the phosphine ligand helps in the reductive elimination step. However, N-heterocyclic carbenes ligand has recently been used in this cross coupling, due to the instability of the phosphine ligand under Suzuki reaction conditions. N-Heterocyclic carbenes are more electron rich and more bulkier than the phosphine ligand. Therefore, both the steric and electronic factors of the N-heterocyclic carbene ligand help to stabilize active Pd(0) catalyst.