Acetals in amidoalkylation of phosphonous carboxylic acids

The use of free phosphonous carboxylic diacids in three–component carbamate version of the Kabachnik–Fields reaction in acetyl chloride medium allows introducing acetals into the reaction sphere to result in phosphinic peptides. The employment of low-stable and functionally substituted aldehydes in the form of acetals provides phosphinic peptides that are difficult to obtain by other methods.