A simple route to novel 2,5-dihydro-1,5,2-diazaphosphinines from primary enamine phosphonates

A simple method for the preparation of phosphorus-containing pyrimidine analogues such as 4,6-disubstituted-2-ethoxy-2,5-dihydro-1,5,2-diazaphosphinine 2-oxides 5 from primary enamine phosphonates and nitriles is described. A similar strategy is used for the synthesis of the corresponding 4,6-difluorinated-1,5,2-diazaphosphinine 2-oxide derivatives 8.