The reaction of diphenyl and dialkyl phosphorochloridates with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Formation of phosphonate diesters via N→C phosphorus migration

Abstract

Diphenyl and neopentylene phosphorochloridates react with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in acetonitrile to form amidine adducts 3 or 10. These undergo further conversion into the corresponding alkene aminals, followed by probable N→C phosphorus migration to produce stable 6-substituted phosphinoyl derivatives of DBU, 6 or 12, respectively. Diethyl phosphorohalidates (chloride and bromide) also form amidine adduct 13 with DBU, but this does not undergo N→C phosphorus migration.