Influence of 1,3-difluorobenzene substituents for palladium-catalyzed direct arylations.
Résumé
The influence of electron-withdrawing and electron-donating substituents (nitro, nitrile, chloro, bromo, methoxy or amino) on 1,3-difluorobenzenes in their palladium-catalyzed direct C2 arylation has been explored. With most substituents, the reaction proceeds nicely using air-stable palladium catalysts (0.5-2 mol-%) and KOAc/DMA. In general, very regioselective C2-arylation was obsd. Moreover, a variety of substituents on the aryl bromide coupling partner (ester, acetyl, formyl, nitro, nitrile, trifluoromethyl, chloro, fluoro or methyl) was tolerated. [on SciFinder(R)]