Regioselective CH Alkylation of Anisoles with Olefins Catalyzed by Cationic Half‐Sandwich Rare Earth Alkyl Complexes

A half sandwich helping: Cationic rare-earth alkyl species generated from half-sandwich rare-earth dialkyl complexes and [Ph3C][B(C6F5)4] can serve as unique catalysts for the CH regioselective alkylation of anisoles with alkenes. The reaction affords either ortho-monoalkylated derivatives or products substituted at the benzylic position, depending on the substrate chosen.