γ‑Carbon Activation through N‑Heterocyclic Carbene/Brønsted Acids Cooperative Catalysis: A Highly Enantioselective Route to δ‑Lactams

A γ-carbon
activation method that operates through N-heterocyclic carbene/Brønsted
acid cooperative catalysis for highly enantioselective synthesis of
δ-lactams is reported. The protocol allows the challenging remote
γ-carbon control of regioselectivity and enantioselectivity
through introduction of an appropriate γ-leaving group in the
enals. The reaction offers good yields and excellent enantioselectivities,
and the resulting cyclic products can be easily converted into high-value
drug-like derivatives.