Co-Catalyzed Direct Addition of Allylic C(sp³)–H Bonds to Ketones

By using Co­(acac)₂/Xantphos with AlMe₃, the C­(sp³)–H bonds of allylarene derivatives were cleaved for reaction with various ketones, affording the homoallylic alcohols in moderate to good yields. The branch/linear selectivity depended on the steric and electronic factors of the ketone electrophiles. The intermediate in this reaction is thought to be a low-valent allylcobalt­(I) species, which exhibits high nucleophilicity toward ketones.