Gold(I)-Catalyzed Polycyclizations of Polyenyne-Type Anilines Based on Hydroamination and Consecutive Hydroarylation Cascade

A hydroamination–double hydroarylation cascade
using aniline derivatives bearing a trienyne moiety as the substrate
was efficiently promoted by a gold­(I) catalyst to produce benzo­[a]­naphtho­[2,1-c]­carbazole derivatives in
good yields. This reaction is applicable to various substituted trienyne-type
anilines, including 2,3-diethynylthiophene derivatives. The reaction
of anilines bearing a tetraenyne and pentaenyne moiety allows direct
construction of highly fused carbazoles by tetra- and pentacyclization,
respectively, through hydroamination and consecutive hydroarylation
without producing any theoretical waste products from the substrates.