Reactions of N-phthalylamino acid chlorides with trialkyl phosphites

Reaction of commercially available trialkyl phosphites with N-phthalylamino acids gave mixtures of seven products, whereas the same reaction carried out with pure triethyl phosphite yielded only the desired 2-(N-phthalytamino)-1-oxoalkanephosphonates. These compounds underwent rearrangement to the same types of products that were obtained with the commercial phosphites. This latter series of reactions was promoted by the presence of dialkyl phosphites.