ortho-Selective C-H addition of N,N-dimethyl anilines to alkenes by a yttrium catalyst

The efficient and selective ortho-alkylation of N,N-dimethyl anilines via C-H addition to alkenes was achieved for the first time using a cationic half-sandwich yttrium catalyst. This protocol constitutes a straightforward and atom-economical route for the synthesis of a new family of tertiary aniline derivatives with branched alkyl substituents, which are otherwise difficult to obtain. DFT calculation studies suggest that the interaction between the yttrium atom and the NMe₂ group plays an important role and the intramolecular C-H activation through a σ-bond metathesis pathway is the rate-determining step, which is consistent with the experimental KIE observations.