Palladium-catalyzed cross-coupling reactions are indispensable tools in molecular syntheses with numerous applications in academia and for the practitioners in the chemical and pharmaceutical industries.

This review summarizes the application of flow technologies for the realization of C–H functionalization reactions, focusing on the main features and benefits of the use of flow compared to batch conditions.

C–H arylations were accomplished with a user-friendly heterogeneous palladium catalyst in the biomass-derived γ-valerolactone (GVL) as an environmentally-benign reaction medium.

Herein we report the unprecedented Fujiwara–Moritani reaction catalysed by the commercially available heterogeneous palladium catalyst Pd/C. The reaction works efficiently in GVL, a biomass derived solvent, in the coupling between variously substituted acetanilides and electron-poor alkenes, with complete selectivity towards the ortho-substitution. Moreover, the catalyst can be easily recycled and reused for consecutive reaction runs. We also developed a continuous-flow procedure, through an easily accessible tailor-made reactor, which allows the production of C–H alkenylated products on grams per hour scale.

Herein we report an efficient procedure for the C–H functionalization of 1,2,3-triazoles in a continuous flow regime applied to a variety of functionalities and to the inter- or intramolecular versions of the process. The continuous-flow protocol is based on the use of a heterogeneous catalyst (Pd/C), a soluble organic base and GVL as the reaction medium. Flow conditions allow an optimal recovery/reuse and durability of the catalyst, which combined with the simple purification of the products and the recovery of the reaction medium make the proposed protocol operationally simple and very efficient in terms of waste minimization as proven by low metal leaching and a low associated E-factor.

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.