RT info:eu-repo/semantics/article
T1 Non‐Chelate‐Assisted Palladium‐Catalyzed Aerobic Oxidative Heck Reaction of Fluorobenzenes and Other Arenes: When Does the C−H Activation Need Help?
A1 Villalba, Francisco
A1 Albéniz, Ana C.
K1 Química
K1 C-H activation
K1 olefination
K1 palladium
K1 Catalysis
K1 metal-ligand cooperation
K1 oxygen
K1 23 Química
AB The pyridone fragment in the ligand [2, 2’-bipyridin]-6(1H)-one (bipy-6-OH) enables the oxidative Heck reaction of simple arenes with oxygen as the sole oxidant and no redox mediator. Arenes with either electron-donating or electron-withdrawing groups can be functionalized in this way. Experimental data on the reaction with toluene as the model arene shows that the C-H activation step is turnover limiting and that the ligand structure is crucial to facilitate the reaction, which supports the involvement of the pyridone fragment in the C-H activation step. In the case of fluoroarenes, the alkenylation of mono and 1,2-difluoro benzenes requires the presence of bipy-6-OH. In contrast, this ligand is detrimental for the alkenylation of 1,3-difluoro, tri, tetra and pentafluoro benzenes which can be carried out using just [Pd(OAc)2]. This correlates with the acidity of the fluoroarenes, the most acidic undergoing easier C H activation so other steps of the reaction such as the coordination-insertion of the olefin become kinetically important for polyfluorinated arenes. The use of just a catalytic amount of sodium molybdate as a base proved to be optimal in all these reactions.
PB Wiley-VCH
SN 1615-4150
YR 2021
FD 2021
LK https://uvadoc.uva.es/handle/10324/65052
UL https://uvadoc.uva.es/handle/10324/65052
LA spa
NO Adv. Synth. Catal. 2021, 363, 4795 – 4804
DS UVaDOC
RD 27-dic-2024