Rhenium-Catalyzed Cyclization via 1,2-Iodine and 1,5-Hydrogen Migration for the Synthesis of 2‑Iodo‑1H‑indenes

A rhenium complex catalyzed the formation of 2-iodo-1H-indene derivatives through iodine and hydrogen migration of 3-iodopropargyl ethers. The reaction proceeded via generation of 1-iodoalkenylrhenium carbene species by sequential 1,2-iodine and 1,5-hydrogen shifts with readily available precursors under neutral conditions. The reaction mechanism and the reactivity of the generated alkenylcarbene species were also investigated.