Intramolecular functional group differentiation as a strategy for the synthesis of bridged bicyclic β-amino acids

Differentiation of identical electrophilic functional groups (carboxylates) by a strategically placed internal nucleophile (an amino group) in cyclic precursors was used as a key general approach to functionalized azabicyclic scaffolds. The utility of the method was demonstrated by the synthesis of three bicyclic β-amino acids (analogues of nipecotic acid), which were prepared in good yields and on a relatively large scale.