Enantioselective Dearomative Difunctionalization of Indoles by Palladium-Catalyzed Heck/Sonogashira Sequence

Abstract

Palladium-catalyzed enantioselective dearomative arylalkynylation of N-substituted indoles, through a Heck/Sonogashira sequence, was established using a new BINOL-based phosphoramidite as the chiral ligand. A wide range of 2,3-disubstituted indolines, bearing vicinal quaternary and tertiary stereocenters, were efficiently constructed in one step with excellent enantioselectivities (up to 97 % ee) and diastereoselectivities (>20:1).

Keywords: alkynes; asymmetric catalysis; dearomatization; heterocycles; palladium.