Silver(Ⅰ)Promotes C4-H Bond Phosphorylation Of 1-Naphthylamine Derivatives With H-phosphonates

A simple and efficient protocol for the direct C-H phosphonation of 1-naphthylamine derivatives with H-phosphonates promoted by silver(I)has been described.This reaction exhibited the high regioselectivity,providing a facile and efficient route to C4-phosphonated 1-naphthylamine derivatives.The reaction goes smoothly under the promotion of Ag2O,KOAc was used as the base,1,2-dichloroethane was chosen as solvent and heated at 120℃ for 16 hours(Scheme 1).This reaction has a wide range of substrate scope,for different kinds of dialkyl phosphonates or alkyl phenyl phosphoinates and 1-naphthylamine substrates with electron donor group,neutral substituent group and weak electron-drawing group,the corresponding phosphorus-substituted 1-naphthylamine derivative was successfully obtained in medium to good yield.Further functionalization of the phosphonated product proves that the method has potential synthetic application.The adding of radical scavenger such as 2,6-ditert-butyl-4-methylphenol(BHT)or 2,2,6,6-tetramethyl-l-piperinedinyloxy(TEMPO)to the reaction system significantly inhibited the reaction,indicating that the reaction might involved a radical process(Scheme 2).