A new polystyrene-type resin loaded with pincer-type imidazolium ionic tag has been very effective in the immobilization of [PdCl4]2− palladium complex leading to a very low leaching of the metal during its use in flow.

The intramolecular coupling of two C(sp3)−H bonds to forge a C(sp3)−C(sp3) bond is enabled by 1,4‐Pd shift from a trisubstituted aryl bromide. Contrary to most C(sp3)−C(sp3) cross‐dehydrogenative couplings, this reaction operates under redox‐neutral conditions, with the C−Br bond acting as an internal oxidant. Furthermore, it allows the coupling between two moderately acidic primary or secondary C−H bonds, which are adjacent to an oxygen or nitrogen atom on one side, and benzylic or adjacent to a carbonyl group on the other side. A variety of valuable fused heterocycles were obtained from easily accessible ortho‐bromophenol and aniline precursors. The second C−H bond cleavage was successfully replaced with carbonyl insertion to generate other types of C(sp3)‐C(sp3) bonds.

An efficient and selective procedure was developed for the direct C2–H arylation of indoles using a Pd‐loaded metal–organic framework (MOF) as a heterogeneous catalyst and the nontoxic biomass‐derived solvent γ‐valerolactone (GVL) as a reaction medium. The developed method allows for excellent yields and C‐2 selectivity to be achieved and tolerates various substituents on the indole scaffold. The established conditions ensure the stability of the catalyst as well as recoverability, reusability, and low metal leaching into the solution.

A heterogeneous reusable palladium(II)-bis(N-heterocyclic carbene) catalyst was prepared and shown to catalyze the intramolecular C(sp 3 )À H activation/cyclization of N-alkyl-2-bromoanilines furnishing indolines. This new catalytic system was based on a bis-imidazolium ligand immobilized on a spaced crosslinked polystyrene support. The iodide ligands on the catalyst played a central role in the efficiency of the process occurring through a "release and catch" mechanism. The heterogeneous nature of the catalyst was further exploited in the design of a continuous-flow protocol that allowed a more efficient recovery and reuse of the catalyst, as well as a very fast and safe procedure.

Herein we report the design and application of the first tube-in-tube packed-bed flow reactor for the development of a heterogeneous palladium catalysed oxidative C–C bond formation process. In particular, we...