Direct Arylation in the Presence of Palladium Pincer Complexes

Abstract

Direct arylation is an atom-economical alternative to more established procedures such as Stille, Suzuki or Negishi arylation reactions. In comparison with other palladium sources and ligands, the use of palladium pincer complexes as catalysts or pre-catalysts for direct arylation has resulted in improved efficiency, higher reaction yields, and advantageous reaction conditions. In addition to a revision of the literature concerning intra- and intermolecular direct arylation reactions performed in the presence of palladium pincer complexes, the role of these remarkably active catalysts will also be discussed.

Benchmarking Strategies of Sustainable Process Chemistry Development: Human-Based, Machine Learning, and Quantum Mechanics

“…Since this is a typical Pd­(0/II) cycle, it is plausible that the mechanism may occur through a base-promoted concerted metalation–deprotonation (CMD) process (Scheme ), as described in the literature. − …”

α-Diimine-based conjugated microporous polymers as heterogeneous ligands for highly efficient palladium-catalyzed direct C–H arylations

“…In contrast, less hindered ligands often result in much lower yields, which could be ascribed to the fast decomposition of the palladium species in the case where protection via C-N Ar rotation is lacking. [41][42][43] Despite significant advancements in these palladium-catalyzed transformations, limitations such as the synthetic difficulty in accessing bulky sterically hindered palladium complexes and the challenges in recycling homogeneous catalysts still exist. [44][45][46] To the best of our knowledge, there have been no reports of heterogeneous ligands stabilizing palladium complexes by suppressing C-N Ar rotation to promote direct C-H arylations of heteroaryls.…”

Organic Synthesis via Transition Metal-Catalysis

“…The first review (by Garazi Urgoitia, Maria Teresa Herrero, Fátima Churruca, Nerea Conde, and Raul SanMartin) reports on the use of palladium pincer complexes as catalysts or pre-catalysts for the direct arylation of arenes with aryl halides or pseudo-halides [2]. This is a particularly important process, which allows aryl-aryl coupling (also intramolecularly) using an arene (or heteroarene) as one coupling partner, with C-H activation.…”