Chemo- and Regioselective Asymmetric Synthesis of Cyclic Enamides through the Catalytic Umpolung Organocascade Reaction of α‑Imino Amides

The
efficient chemo- and regioselective catalytic asymmetric syntheses
of enamides, which are important core structures of bioactive natural
products, have been achieved through the first umpolung organocascade
reaction of α-imino amides. A variety of enamides have been
synthesized enantioselectively in high yields with up to 99% ee. Notably,
both enantiomers of the products can be selectively prepared by the
simple pretreatment of the substrate. Mechanistic studies reveal that E/Z-geometry information from the substrate
is transferred to the product. The present method can be applied to
a wide range of α-imino amides, irrespective of the electronic
nature of the substituents.