Merging photoredox catalysis with transition metal catalysis: site-selective C4 or C5-H phosphonation of 8-aminoquinoline amides

A simple and efficient protocol for the transition metal-catalyzed site-selective C-H phosphonation of 8-aminoquinolines with diarylphosphine oxide or H-phosphonate diesters was developed via a photoredox process. This reaction features high regioselectivity at the C4 or C5 position under mild and simple conditions (with a catalytic amount of silver salt at room temperature). Note that the C4 position of 8-aminoquinoline is an unusual reactive site.