Palladium-Catalysed Cross-Coupling Reactions Controlled by Noncovalent Zn···N Interactions

Mohamed Kadri (1, 2, 3) , Jingran Hou (1) , Vincent Dorcet (1) , Thierry Roisnel (1) , Lazhar Bechki (2) , Abdellah Miloudi (3) , Christian Bruneau (1) , Rafael Gramage-Doria (1)

1 ISCR - Institut des Sciences Chimiques de Rennes
2 Département de Chimie
3 Laboratoire de Chimie Fine

Non-covalent interactions between halopyridine substrates and catalytically inert building blocks, namely zinc(II)-porphyrins and zinc(II)-salphens, influence the catalytic outcome of Suzuki-Miyaura and Mizoroki-Heck palladium-catalysed cross-coupling reactions. The weak Zn⋅⋅⋅N interactions between halopyridine substrates and zinc(II)-containing porphyrins and salphens, respectively, were studied by a combination of H NMR spectroscopy, UV/Vis studies, Job-Plot analysis and, in some cases, X-ray diffraction studies. Additionally, the former studies revealed unique supramolecular polymeric and dimeric rearrangements in the solid state featuring weak Br⋅⋅⋅N (halogen bonding), C-H⋅⋅⋅π, Br⋅⋅⋅π and π⋅⋅⋅π interactions. The reactivity of halopyridine substrates in homogeneous palladium-catalysed cross-coupling reactions was found to correlate with the binding strength between the zinc(II)-containing scaffolds and the corresponding halopyridine. Such observation is explained by the unfavourable formation of inactive over-coordinated halopyridine⋅⋅⋅palladium species. The presented approach is particularly appealing for those cases in which substrates and/or products deactivate (or partially poison) a transition-metal catalyst.

Mots clés: palladium; porphyrin; pyridine; salphen; noncovalent interactions

Domaines: Catalyse; Chimie organique

Mohamed Kadri, Jingran Hou, Vincent Dorcet, Thierry Roisnel, Lazhar Bechki, et al.. Palladium-Catalysed Cross-Coupling Reactions Controlled by Noncovalent Zn···N Interactions. Chemistry - A European Journal, 2017, 23 (21), pp.5033-5043. ⟨10.1002/chem.201604780⟩. ⟨hal-01507248⟩