Gold(I)-Catalyzed Cascade Approach for the Synthesis of Tryptamine-Based Polycyclic Privileged Scaffolds as α₁‑Adrenergic Receptor Antagonists

An efficient and facile gold­(I)-catalyzed one-pot cascade protocol has been developed for the synthesis of tryptamine-fused polycyclic privileged structures through the treatment of substituted tryptamines and 2-ethynylbenzoic acids or 2-ethynylphenylacetic acids. This strategy features the formation of one C–C bond and two C–N bonds with high yields and broad substrate tolerance. The selected reduced target molecules are validated to perform as α₁-adrenergic receptors antagonists. The most potent one, 4bh, exhibits an IC₅₀ value of 277 nM on α_1A subtype with a selectivity ratio of 15.8 over α_1B subtype.