A self-relay
rhodium(I)-catalyzed cyclization of alkyne–azides
with two σ-donor/π-acceptor ligands (isonitriles and CO)
to form sequentially multiple-fused heterocycle systems via tandem
nitrene transformation and aza-Pauson–Khand cyclization has
been developed. In this approach, an intriguing chemoselective insertion
process of isonitriles superior to CO was observed. This reaction
provides an alternative strategy to synthesize functionalized pyrrolo[2,3-<i>b</i>]indole scaffolds
