Palladium-Catalyzed Benzylic Arylation

Key words

cross-coupling - benzylic arylation - palladium

Significance

The authors report a new direct palladium-catalyzed arylation of benzylic sp^³ C-H atoms. The mild reaction conditions of this protocol require only low catalyst loadings (2.5 mol%) and allow a wide functional group tolerance on the benzylic scaffold as well as the aryl moiety. No preactivation of the benzylic position is necessary.

Comment

Aromatics with electron-withdrawing and -donating groups could be introduced in the benzylic position equally well. The palladium source was found to be less important in the reaction; however, the nature of the ligand had a significant effect on the ratio of mono- to bisarylated product. For the same reason equimolar amounts of both coupling partners are used.