A Facile Approach to 3,4‐Oxepino‐Fused Tricyclic Indoles from MBH‐Acetates of Acetylenic Aldehydes via Successive Allylic Substitution/Intramolecular [3+2] Annulation†

Abstract Herein, we present our findings on the synthesis of 3,4‐oxepino‐fused indoles by a two‐step reaction sequence involving an initial allylic substitution followed by Rh(III)‐catalyzed intramolecular [3+2] annulation via C−H activation starting from Morita‐Baylis‐Hillman (MBH) acetates of acetylenic aldehydes. The strategy is amenable to broad range of MBH acetates providing a facile access to 3,4‐oxepino‐fused indoles in good yield.