Phosphonite Ligand Design for Nickel-Catalyzed 2-Methyl-3-butenenitrile Isomerization and Styrene Hydrocyanation

The synthesis of a series of novel chelating bisphosphonite ligands with a bridged dihydroanthracene scaffold is described. First-generation derivatives showed a strong tendency for the formation of catalytically inactive Ni-0 bis-chelate complexes. The solid state structures of these complexes allowed the design of tailor-made second-generation ligands for nickel-catalyzed 2-methyl-3-butenenitrile isomerization with exceptionally high activity. The second-generation catalyst also showed good catalytic performance in the hydrocyanation of styrene.