Julien Roger

Ortho-Functionalized Aryltetrazines by Direct Palladium-Catalyzed C-H Halogenation: Application to Fast Electrophilic Fluorination Reactions.

A general catalyzed direct C-H functionalization of s-tetrazines is reported. Under mild reaction conditions, N-directed ortho-C-H activation of tetrazines allows the introduction of various functional groups, thus forming carbon-heteroatom bonds: C-X (X=I, Br, Cl) and C-O. Based on this methodology, we developed electrophilic mono- and poly-ortho-fluorination of tetrazines. Microwave irradiation was optimized to afford fluorinated s-aryltetrazines, with satisfactory selectivity, within only ten minutes. This work provides an efficient and practical entry for further accessing highly substituted tetrazine derivatives (iodo, bromo, chloro, fluoro, and acetate precursors). It gives access to ortho-functionalized aryltetrazines which are difficult to obtain by classical Pinner-like syntheses.

Palladium C–N bond formation catalysed by air-stable robust polydentate ferrocenylphosphines: a comparative study for the efficient and selective coupling of aniline derivatives to dichloroarene

The arylation of aniline derivatives with dichloroarenes under a low palladium content (below the currently used 5 to 10 mol%) was studied using nine different ferrocenylphosphine ligands, including the easily accessible 1,1′-bis(diphenylphosphino)ferrocene, DPPF. The electron-enriched air-stable tridentate ferrocenylpolyphosphine 1,2-bis(diphenylphosphino)-1′-(diisopropylphosphino)-4-tert-butylferrocene, L5, employed in 2 mol% in combination with 1 mol% [PdCl(η3-C3H5)]2 allows an efficient and selective coupling, while such demanding substrates currently induce chloroarene homocoupling and/or dehalogenation processes. The scope and limitation of the optimized system are explored, with a focus on electron-poor fluoroanilines (deactivated nucleophiles) and electron-rich methylated and methoxylated dichlorobenzenes (deactivated electrophiles).