Chiral Brønsted Acid-Catalyzed Intramolecular Asymmetric Allylic Alkylation of Indoles with Primary Alcohols

Herein,
chiral Brønsted acid-catalyzed intramolecular asymmetric
allylic alkylation of indoles with allylic primary alcohols is described.
The allyl alcohols were directly employed as the allylic precursors
in this metal-free protocol, without preactivation or any additional
activating reagents. This method provides the convenient synthesis
of a broad range of functionalized tetrahydrocarbazoles in excellent
yields (≤97%) with good enantioselectivity (≤93% ee).
The optimal conditions are compatible for gram-scale reaction.