Benzylarylation of N-Allyl Anilines: Synthesis of Benzylated Indolines

An unprecedented benzylic C−H functionalization of methyl arenes across unactivated alkenes is presented. In the presence of MnCl2·4H2O and di-tert-butyl peroxide (DTBP), N-allyl anilines underwent benzylation/cyclization cascade to give benzylated indolines, which are a previously unmet synthetic goal. This protocol features simple operation, broad substrate scope, and great exo selectivity.