Chemoselectivity of the reactions of haloacetonitriles with hydrogen phosphonates: the dramatic effect of the nature of the halogen atom

Perfluoro(chloro) acetonitriles react with (RO)2POH (R = Et, Ph) by two competitive routes: addition to the CN bond affording the respective N-unprotected iminophosphonates, or reductive dehalogenation leading to chloro(fluoro) acetonitriles and the respective halogenophosphates, (RO)2P(O)X (X = Cl, F). The direction and chemoselectivity of the reactions are controlled by the nature and quantity of halogen atoms in the starting nitrile.