Exploiting the Reactivity of Fluorinated 2-Arylpyridines in Pd-Catalyzed C-H Bond Arylation for the Preparation of Bright Emitting Iridium(III) Complexes
Résumé
Pd-catalyzed C-H bond arylation applied to 2-(2,4-difluorophenyl)-5-(trifluoromethyl)pyridine (1) and 2-(3,5-difluorophenyl)-5-(trifluoromethyl)pyridine (5) allows the access to two families of Ir(III) complexes, charge-neutral and cationic species. The reaction is regioselective since only the C3- or C4-position of the fluorinated phenyl ring of 1 or 5 is readily functionalized - namely the C-H bond flanked by the two fluorine atoms which is the most acidic - which allows the electronic control of the reactive site. A range of electron-withdrawing (CN, CO(2)Et, C(O)Me) substituents on the aryl group has been incorporated leading to the pro-ligands (1, Ar-2,4-dFppy; 2, Ar = p-C(6)H(4)-CN; 3, Ar = p-C(6)H(4)-CO(2)Et; 4, Ar = p-C(6)H(4)-C(O)Me; 5, and Ar-3,5-dFppy; 6, Ar = p-C(6)H(4)-CO(2)Et). The unsubstituted complexes F1/G1 and F1/G5 featuring 1 and 5, respectively, as C
Domaines
Chimie
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