Efficient synthesis of racemic β-aminophosphonates via aza-Michael reaction in water

Water as a solvent significantly accelerates the addition of various amines to diethyl vinylphosphonate to yield β-aminophosphonates without any catalyst compared to known procedures for such aza-Michael reactions. The products are obtained in quantitative yields and high purity over short reaction times. Using a reactant ratio (vinylphosphonate/amine) of 2:1 resulted in double phosphorylation of primary amines.

Remarkable rate acceleration is reported for the aza-Michael reaction of diethyl vinylphosphonate with amines in water to yield β-aminophosphonates in quantitative yields.