Synthesis of New Molecular Scaffolds: 3-Aza-7,9-Dioxa-Bicyclo[4.2.1]Nonane (8-exo BTKa) and 3-Aza-8,10-Dioxa-Bicyclo[5.2.1]Decane (9-exo BTKa) Carboxylic Acids

Two classes of enantiopure molecular scaffolds were prepared, whose lactam structure formally derives from the coupling between tartaric acid and beta- or gamma-ketoamines. We labelled these compounds as 8-exo and 9-exo BTKa, indicating the lactam size (8- and 9-membered ring, respectively). Starting from beta- and gamma-nitroketones, the synthesis involves the ketal formation by (R,R)-dimethyl tartrate. The subsequent amide bond formation occurs during the hydrogenation of the nitro group over Raney-Ni and no expected open chain amine was observed.