Intramolecular Didehydro-Diels–Alder Reaction for the Synthesis of Benzo- and Dihydrobenzo-Fused Heterocycles

Using an intramolecular didehydro-Diels–Alder reaction, ene–yne substituted pyrroles, thiophenes, and furans afford functionalized indoles, benzothiophenes, and benzofurans and the corresponding dihydroaromatic products. Product selectivity for the aromatic or dihydroaromatic product is controlled by the reaction conditions, which vary depending upon the substrate.