Organocatalytic Tandem Synthesis of Chiral Hexacyclic Bisindoles from Propargylic 3-Methyleneindoles with 2-Indolylmethanols

Org Lett. 2023 Sep 15;25(36):6654-6658. doi: 10.1021/acs.orglett.3c02476. Epub 2023 Sep 6.

Abstract

A novel chiral phosphoric acid-catalyzed tandem regioselective 1,6-addition/double intramolecular nucleophilic addition annulation of the propargylic 3-methyleneindoles in situ generated from α-indolyl propargylic alcohols with 2-indolylmethanols has been developed. The methodology afforded the new chiral trifluoromethyl pentalenobisindoles bearing an all-carbon quaternary stereogenic center in generally good yields with excellent enantioselectivities.