A novel method for the enantioselective synthesis of nitrogen containing compounds has been achieved. The oxidative rearrangement of N-acyl 2-furylamines, termed the Aza-Achmatowicz rearrangement, generates a product with a high density of differentiable functionalities. This characteristic of the product makes it an excellent building block for the synthesis of nitrogenous substances of biomedical interest. Optically pure building blocks are also available via the Aza-Achmatowicz rearrangement. The generation of chirality in the starting furyl derivative is obtained by a simple, inexpensive chemoenzymatic method utilizing papain. The chemical reactivity of these heterocycles has been thoroughly explored, and utilized in the synthesis of (+)-desoxoprosopinine, deoxyazasaccharides, izidinie alkaloid systems, β-lactams, and unusual amino acids.