A Photosensitizer for N-O Bond Activation: 2,7-Br-4CzIPN-Catalyzed Difunctionalization of Alkenes with Oxime Esters.

We developed 2,4,5,6-tetrakis(2,7-dibromo-9 H -carbazol-9-yl)isophthalonitrile (2,7-Br-4CzIPN) as a new photosensitizer for the energy-transfer-driven N-O bond dissociation of oxime esters. In the presence of 2,7-Br-4CzIPN, difunctionalization of alkenes with oxime esters, including oxyimination, aminocarboxylation, and amidylimination, could afford a variety of versatile molecules in good yields with excellent regioselectivity, which widely occur in natural products and drugs. Our theoretical investigations and experiments have demonstrated that 2,7-Br-4CzIPN has unique photophysical properties, favorable triplet energy, and excellent photocatalytic activity.