Pd/Brønsted acid catalysed intramolecular N-allylation of indoles and pyrroles with alkynes for the synthesis of N-fused heterocycles

We, herein, report a Pd(0) and Bronsted acid-catalyzed redox-neutral intramolecular N-allylation of indoles and pyrroles with alkynes for the synthesis of biologically important imidazolidinone-fused N-heterocycles. The allylation is completely atom-economical and is applicable to a wide range of substrates. The methodology eliminates the use of a leaving group or an oxidizing agent, often employed for the allylation of nucleophiles. To the best of our knowledge, N-allylation of indoles and pyrroles with alkynes has not been reported to date.

Automated summary

In this article, a novel catalytic reaction using Pd(0) and Bronsted acid is reported for the synthesis of biologically important imidazolidinone-fused N-heterocycles through redox-neutral intramolecular N-allylation of indoles and pyrroles with alkynes. This atom-economical method is applicable to a wide range of substrates and eliminates the need for leaving groups or oxidizing agents commonly used in traditional allylation reactions.