Photoinduced decarboxylative azidation of cyclic amino acids.

The direct decarboxylative azidation of cyclic α-amino acids has been achieved via visible light-mediated organo-photoredox catalysis. This synthetic strategy allows the simple preparation of azide-contaning building blocks and has been used in the selective modification of N-terminal proline residues of two di-peptides.

Gold(I)-Catalyzed Enantioselective Annulations between Allenes and Alkene-Tethered Oxime Ethers: A Straight Entry to Highly Substituted Piperidines and aza-Bridged Medium-Sized Carbocycles.

Piperidine scaffolds are present in a wide range of bioactive natural products and are therefore considered as highly valuable, privileged synthetic targets. In this manuscript, we describe a gold-catalyzed annulation strategy that allows a straightforward assembly of piperidines and piperidine-containing aza-bridged products from readily available alkene-tethered oxime ethers (or esters) and N-allenamides. Importantly, we demonstrate the advantages of using oxime derivatives over imines, something pertinent to the whole area of gold catalysis, and provide relevant mechanistic experiments that shed light into the factors affecting the annulation processes. Moreover, we also describe preliminary experiments demonstrating the viability of enantioselective versions of the above reactions.