Synthesis of N‐Fused Tricyclic Indoles by a Tandem [1,2] Stevens‐Type Rearrangement/1,2‐Alkyl Migration of Metal‐Containing Ammonium Ylides

An alkyne moiety is activated efficiently with a [W(CO)6] or [ReBr(CO)5] catalyst in the presence of an amine functionality in the title reaction of N-(2-alkynylphenyl)amines. The resulting ammonium ylides undergo rearrangement to form a variety of N-fused polycyclic indole derivatives (see scheme; n=1,2; R=alkyl, Ph).