Highly Enantioselective Iridium-Catalyzed Coupling Reaction of Vinyl Azides and Racemic Allylic Carbonates

The iridium-catalyzed
enantioselective coupling reaction of vinyl
azides and allylic electrophiles is presented and provides access
to β-chiral carbonyl derivatives. Vinyl azides are used as acetamide
enolate or acetonitrile carbanion surrogates, leading to γ,δ-unsaturated
β-substituted amides as well as nitriles with excellent enantiomeric
excess. These products are readily transformed into chiral N-containing
building blocks and pharmaceuticals. A mechanism is proposed to rationalize
the chemoselectivity of this coupling reaction.