Chiral Lewis Acid Catalyzed Reactions of alpha-Diazoester Derivatives: Construction of Dimeric Polycyclic Compounds

An unexpected homologation/dyotropic rearrangement/interconversion/[3+2] cycloaddition cascade reaction of alpha-diazoester-terminated N-propyl-substituted isatin derivatives was achieved in the presence of a chiral N,N'-dioxide/Sc-III catalyst. This catalytic manifold allows rapid construction of several classes of dimeric polycyclic compounds with good yields and high levels of diastereo- and enantioselectivity (up to 99% ee). Furthermore, macrocyclic dimers can be obtained by an intermolecular homologation process.