Synthesis of Cyclopenta[b]indoles via Rhodium‐Catalyzed Cascade Migration‐Annulation of 1‐Sulfonyl‐1,2,3‐triazoles and Indoles

Abstract A rhodium‐catalyzed cascade 1,3‐sulfinate migration, intermolecular [3+2] annulation of 1‐sulfonyl‐1,2,3‐triazoles and indoles was achieved. The one‐pot protocol provided a method to construct cyclopenta[ b ]indoles bearing four stereocenters in 45% to 99% yields with 1.6:1 to >20:1 diastereoselectivities. In addition, cyclopenta[ b ]indoles could be transformed into a variety of functionalized compounds, demonstrating the synthetic value of this migration‐annulation strategy in ring system synthesis. magnified image