Cooperative Photoredox and Asymmetric Catalysis

Chemical processes combining visible-light-activated redox catalysis with asymmetric catalysis are reviewed, including enamine catalysis in the presence or absence of an additional photoredox sensitizer, phase transfer catalysis exploiting an in situ -generated electron donor-acceptor complex, photosensitized chiral Lewis acid catalysis, and photoactivated nickel-catalyzed asymmetric cross-couplings. The transfer of a single electron leads to intermediate radical ions, whose strongly modulated reactivities can be exploited for asymmetric catalysis in a novel fashion. All processes discussed here are redox neutral so that the electron serves as a real catalyst which cooperates with an asymmetric catalyst for the overall asymmetric transformation.