Convenient one-pot synthesis of 9H-carbazoles by microwave irradiation employing a green Pd-based nanocatalyst

H. SEBASTIÁN STEINGRUBER; PAMELA MENDOROZ; MARÍA A. VOLPE; DARÍO C. GERBINO

SYNTHESIS-STUTTGART

GEORG THIEME VERLAG KG

Año: 2021 vol. 53 p. 4048 - 4058

0039-7881

An efficient palladium-catalyzed tandem reaction for the one-pot synthesis of 9H-carbazoles under microwave irradiation is developed. This approach involves a sequential Buchwald‐Hartwig amination and a direct arylation from affordable and inexpensive anilines and 1,2-dihaloarenes. Forthe development of this purpose, a novel and magnetically recoverable palladium nanocatalyst supported on a green biochar under ligand-free conditions is used. Compared to 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 asmall library of 9H-carbazoles with high yields and good regioselectivity. This procedure represents the first example in the direct synthesis of carbazoles using a heterogeneous palladium nanocatalyst from commercial precursors. To examine the application of this protocol, a direct and scalable synthesis of the bioactive carbazole alkaloid clausenalene from commercially available starting materials is described.