Synthesis of Pyrroles Using InCl₃ as a Multifunctional Catalyst

Significance

A one-pot propargylation-amination-cycloisomerization protocol for the synthesis of highly substituted pyrroles from simple starting materials (1,3-dicarbonyls, primary amines and propargylic alcohols) is reported. Extensive screening of reaction conditions led to the development of InCl₃ as a multifunctional catalyst for this process. The substrate scope was extensively studied and the results show moderate to very good yields of products. However, the reaction fails when diethyl malonate primary or secondary aliphatic propargylic alcohols or ammonium acetate or chloride are used as substrates. Instead, ammonium carbamate gave the desired result in the synthesis of N-H pyrroles.