Bicyclic bases Ambident anions as intramolecular nucleophiles in the formation of 2-oxa-5-azabicyclo[2.2.1] heptane derivatives

The intramolecular cyclization of the ambident anion 5 derived from condensation of N, O-ditosylhydroxy-L-proline acid chloride with dimethyl malonate anion was studied under a variety of reaction conditions. Cyclization occurred solely by O-alkylation to give 2-oxa-5-azabicyclo[2.2.1 ]heptanes. The NMR speetra of the hicyclo compounds are diseussed.