Catalytic Enantioselective α-Allenylation of Acetonitrile

The widespread occurrence of the cyanomethyl group in bioactive molecules and natural products has triggered the development of efficient methods for its incorporation. Functionalization through the direct use of acetonitrile as C2 synthon remains challenging due to the poor acidity of its α-protons. To avoid this restriction, we utilized 2-azido allylic alcohol as an acetonitrile enolate surrogate in the first enantioselective α-allenylation of acetonitrile. Using branched allenylic alcohols as the allenylic electrophile under cooperative iridium and Lewis acid catalysis, this base-free protocol proceeds under mild conditions to afford α-allenylic acetonitriles in moderate to good yields with uniformly high enantioselectivity.