One‐Pot Synthesis of 2‐Substituted Indoles and 7‐Azaindoles via Sequential Alkynylation and Cyclization of 2‐Iodo‐N‐mesylarylamines and Alkynes in the Presence of Cu₂O

Abstract

A one‐pot process was developed to synthesize in moderate to high yield a series of 2‐substituted indoles and 7‐azaindoles starting from 2‐iodo‐N‐mesylarylamines and terminal alkynes in the presence of Cu2O in DMF at 90–120 °C. Without isolation of any intermediate, our optimized conditions enabled the introduction of ester, phenyl, hydroxymethyl, hydroxyethyl, N‐Boc‐aminomethyl, and methyl at the 2‐postion of indoles and 7‐azaindoles. The reaction tolerates a variety of substrates containing halogens, or acid‐ or base‐sensitive functional groups without requiring a Pd catalyst, a ligand, or a base.