Phase-Transfer-Catalyzed Michaelis-Becker Reaction

Article abstract of DOI:10.1021/jo00338a025

Dialkyl hydrogen phosphonates or dialkylphosphine oxides are conveniently and efficiently alkylated by alkyl chlorides to produce dialkyl alkylphosphonates or trialkylphosphine oxides, respectively, by aqueous sodium hydroxide in a liquid-liquid phase-transfer-catalyzed reaction.Despite the hydrolytic instability of dialkyl hydrogen phosphonates, their reaction with chloroacetamides in the two-phase system can provide dialkyl (carbamoylmethyl)phosphonates (RO)2P(O)CH2C(O)NR'R" in 90percent yields and crude purities.Many of these products have unique utility as solvent extraction reagents for the fractionation of hazardous radionuclides.The new route is not plagued by the side reactions typical of conventional Arbuzov or Michaelis-Becker syntheses, which seriously limit yields and crude product purities.It does not require anhydrous conditions or the use of alkali metals, alkoxides, or hydrides and provides access to products outside the scope of conventional routes.