Ozonization and reduction of alfa-methylene N-(ethoxycarbonyl)- beta-amino phosphonic esters

N-(Ethoxycarbonyl)- beta-amino- alfa-methylene phosphonic esters give N-(ethoxycarbonyl)- -amino- -hydroxy phosphonic esters by ozonization and subsequent reduction with a large excess of NaBH4. If there is a small excess of NaBH4 or if the intermediate is treated with methanolic NaOH-CH2Cl2 an anomalous ozonolysis occurs, affording N-(ethoxycarbonyl)- beta-aminomethyl carboxylic esters due to the cleavage of both the C C double bond and the adjacent C P single bond.