Palladium‐Catalyzed Cross‐Dehydrogenative Coupling of <i>o</i>‐Xylene: Evidence of a New Rate‐Limiting Step in the Search for Industrially Relevant Conditions

An efficient cross‐dehydrogenative coupling of o‐xylene under neat conditions, which brings important industrial benefits towards the synthesis of a monomer used in polyimide resins, is reported. The catalyst based on the combination of Pd/N ligand/carboxylate=1:1:2 does not require a Cu cocatalyst and proceeds at 11 bar of O2 pressure. Evaluation of the deuterium kinetic isotope effect (KIE) provides evidence for three different rate‐determining steps, which depend on the reaction conditions (medium, temperature). Under the reported neat conditions, the dissociation of a carboxylate‐bridged dimer to generate a more reactive monometallic Pd species is proposed to be the rate‐limiting step

S,O-Ligand-Promoted Pd-Catalyzed C-H Olefination of Thiophenes

SO good. An efficient PdII catalyzed C−H olefination of thiophenes has been developed using an easily accessible bidentate S,O‐ligand. The catalytic system promotes the C‐2 olefination in a wide range of thiophenes including 3‐substituted thiophenes, under mild conditions

Recent Developments in Palladium-Catalysed Non-Directed C-H Bond Activation in Arenes

Over the past decades, organic chemists have focussed on developing new approaches to directed C–H functionalisations, where the site selectivity is steered by the presence of a directing group (DG). Nonetheless, in recent years, more and more non-directed strategies are being developed to circumvent the requisite directing group, making C–H functionalisations more generic. This short review focuses on the latest developments in palladium-catalysed non-directed C–H functionalisations of aromatic compounds