The reaction of diethyl N-acetyl-N-methylphosphoramidate 1 with aldehyde in
the presence of LDA at -70 degrees C results in the formation of the unsta
ble oxyanion 6 which undergoes intramolecular rearrangement involving migra
tion of a phosphoryl group from nitrogen to oxygen affording an amide anion
8, Subsequent proton transfer in 8 followed by elimination of phosphate an
ion provides the respective alpha,beta-unsaturated N-methylcarboxamide 4, T
he formation of considerable amounts of diethyl N-methylphosphoramidate 5 i
s also always observed.