Visible-Light-Driven Iron-Catalyzed Intermolecular Benzylic C(sp 3 )-H Amination with 1,2,3,4-Tetrazoles.

A visible-light-driven iron-catalyzed C(sp 3 )-H amination of diphenylmethane derivatives with 1,2,3,4-tetrazoles under mild conditions has been developed. The reaction proceeds with photosensitizer-free conditions and features satisfactory to good yields. Mechanistic studies revealed that the reaction proceeded via an iron-nitrene intermediate, and H atom abstraction was the rate-determining step. Computational studies showed that the denitrogenation of 1,2,3,4-tetrazole depends on the conversion of the sextet ground state of 1,2,3,4-tetrazole-bounding iron species to the quartet spin state under visible-light irradiation.