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

摘要

Herein, we present our findings on the synthesis of 3,4- oxepino-fused indoles by a two-step reaction sequence involv- ing 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 alde- hydes. The strategy is amenable to broad range of MBH acetates providing a facile access to 3,4-oxepino-fused indoles in good yield.