It has recently been reported'that ethyl N-acetyl-a,@-dehydroalaninate reacts with some 1, 3- dipoles in 1, 3-dipolar cycloadditions which have proved to proceed regiospecifically regardless of the presence of the acetamido group which exercises a strong directing effect on the addition of electrophilic reagents to the double bond, 2 to afford geminally functionalized heterocyclic amino carboxylic acids.
