Reactivity divergence in the cyclization of terminal epoxides all-carbon-tethered to indoles

We report that indole-all-carbon-tethered, geminal disubstituted terminal epoxides exhibit tether-position-dependent divergent reactivity with an overstoichiometric amount of BF₃·OEt₂. Specifically, indole C4-, C3-, and C2-tethered epoxides undergo different cascade reactions to deliver cyclohepta[<i>cd</i>]indoles, cyclopenta[<i>b</i>]indoles, and carbazoles, respectively, highlighting a unified yet divergent strategy for the construction of indole-fused carbocycles.