**Carlos Santiago, Nuria Sotomayor \* and Esther Lete \***

Departamento de Química Orgánica II, Facultad de Ciencia y Tecnología, Universidad del País Vasco/Euskal Herriko Unibertsitatea UPV/EHU. Apdo. 644. 48080 Bilbao, Spain; carlos.santiago@ehu.es

**\*** Correspondence: nuria.sotomayor@ehu.es (N.S.); esther.lete@ehu.es (E.L.)

Academic Editors: José Pérez Sestelo and Luis A. Sarandeses Received: 27 June 2020; Accepted: 15 July 2020; Published: 16 July 2020

**Abstract:** Di(hetero)aryl ketones are important motifs present in natural products, pharmaceuticals or agrochemicals. In recent years, Pd(II)-catalyzed acylation of (hetero)arenes in the presence of an oxidant has emerged as a catalytic alternative to classical acylation methods, reducing the production of toxic metal waste. Different directing groups and acyl sources are being studied for this purpose, although further development is required to face mainly selectivity problems in order to be applied in the synthesis of more complex molecules. Selected recent developments and applications are covered in this review.

**Keywords:** C-H activation; acylation; palladium; arenes; heteroarenes
