A regio‐ and stereocontrolled solution for a selective modification at the C‐2 or C‐4 position of N‐acetylneuraminic acid involves the use of allylic substitution catalyzed by palladium. As illustrated in the scheme, regioselective malonylation is under the strict influence of the ligands associated with the allylpalladium complex.
stoichiometric preparation and study of the highly probable complexes involved in the catalytic reaction. Reactions of this type were also applied to other nucleophiles for the construction of C-C, C-N, and C-O bonds, leading to the major formation of the C-4 regioisomers. The selective transformation of some of the substitution products provided easy access to a variety of modified sialicacid derivatives