Direct Arylation-Based Synthesis of Carbazoles Using an Efficient Palladium Nanocatalyst under Microwave Irradiation

H Sebastián Steingruber,María A Volpe,Darío C Gerbino,Pamela Mendioroz

doi:10.3390/ecsoc-24-08314

Abstract

Herein, an eco-friendly palladium-catalyzed tandem reaction for the one-pot synthesis of carbazoles under microwave irradiation is reported. This approach involves an amination and a direct arylation from available and inexpensive anilines and 1,2-dihaloarenes. For the development of this purpose, a novel recoverable palladium nanocatalyst supported on a green biochar under ligand-free conditions is used. Compared with other existing palladium-based protocols, the present synthetic methodology shows a drastic reduction in reaction times and excellent compatibility with different functional groups, allowing to obtain a small library of carbazoles with high yields and regioselectivity. The novel heterogeneous palladium nanocatalyst can be recycled and reused up to five times without significant loss activity.

Highlights

9H-carbazole constitutes a predominant nitrogen-containing heterocyclic compound present in both synthetic and naturally occurring alkaloids
An extensive amount of research has been dedicated to introducing structural modifications to natural occurring carbazoles, as well as the synthesis of brand-new derivatives and finding new and efficient ways to obtain them from readily available, lowcost materials
The corresponding carbazole 3 was obtained in 19% yield when our novel PdNPs/BC was used under microwave irradiation

Summary

Introduction

9H-carbazole constitutes a predominant nitrogen-containing heterocyclic compound present in both synthetic and naturally occurring alkaloids. An extensive amount of research has been dedicated to introducing structural modifications to natural occurring carbazoles, as well as the synthesis of brand-new derivatives and finding new and efficient ways to obtain them from readily available, lowcost materials. In this context, direct-arylation of arenes is an outstanding strategy from an economic and environmental point of view in cross-coupling reactions, using stoichiometric quantities of organometallic reactants. The most interesting would be the chlorides, owing to their low costs and wide diversity [4]

Methods

Results

Conclusion