A One-Pot Relay Sc(III)/Base-Promoted Addition/Cyclization of 1-(<i>o</i>-Aminophenyl)prop-2-Ynols and S/C Nucleophiles: Synthesis of 3-Sulfenylindole and 3-Arylindole Derivatives

An efficient strategy for the construction of 3-sulfenylindoles and 3-arylindoles based on a one-pot relay Sc(III)/base-promoted Michael addition/cyclization/aromatization process has been developed. Different types of nucleophiles (thio- and carbon nucleophiles) react with <i>aza</i>-alkynyl <i>o</i>-quinone methides (<i>aza</i>-<i>o</i>-AQMs) generated in situ from 1-(<i>o</i>-aminophenyl)prop-2-ynols to afford the indole derivatives in moderate to excellent yields. This method displays the advantages of mild conditions, simple starting materials, and broad substrate scope.