The 1-substituted title compounds can undergo the azaphospha-Cope rearrangement to give the corresponding (3-butenylimino)phosphine derivatives, which can be trapped by hexanol to afford the corresponding hexyl phenyl(3-butenylamido)phosphonates predominantly, whereas 1,1-disubstituted ones give the nucleophilic substitution products mainly. The activation parameters are presented for the reaction of 1-(4-nitrophenyl) derivative.