A new nitrogen-to-oxygen phosphoryl migration

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.