N-Heterocyclic Carbene-Phosphinidene Adducts: Synthesis, Properties, and Applications

Syntheses, properties, and reactivity of N-heterocyclic carbene-phosphinidene adducts are reviewed. These adducts, formally built by combining a phosphinidene with a carbene, are characterized by high nucleophilicity at the phosphorus atom. The main types of reactivity these adducts exhibit are: Lewis-base reactivity towards main group and organic compounds as well as transition-metal complexes, substitution reactions at the phosphorus atom with main group compounds and transition-metal complexes, and phosphinidene transfer reactions resulting in C-P bond cleavage. These differ substantially from the classic phosphaalkenes.