Alkali Ion Controlled Chemoselective Indolation of Allylic Alcohols by Base Catalysis

Abstract

Although the transition-metal-catalyzed cascade reaction of allylic alcohols has achieved great success, there are rare selective examples catalyzed only by bases. Here, We presented an efficient chemoselective catalytic system for the synthesis of valuable γ-indolation phenylpropanol and bis(indolyl)methane derivatives mediated by transition-metal-free base and tuned through alkali metal ion. This protocol having a wide range of substrates and functional group tolerance can be directly applied to the gram scale reactions and further transfers to useful intermediates. Experimental and theoretical studies have shown that cesium ions and sodium ions can precisely regulate the different hydrogen migration pathways of allylic alcohols.