Chiral Bifunctional Photocatalysts with Aromatic Ketones as Photosensitizers.

Because the biological activity of a molecule is directly linked to its three-dimensional configuration, the preparation of chiral compounds is a central discipline in synthetic organic chemistry. With the exploitation of photoredox catalysis that gives access to open-shell (radical) intermediates under mild and sustainable conditions, unprecedented molecular architectures can now be synthesized. However, the parent enantioselective transformations have been developed at a slower pace because suppressing non-catalyzed background reactivities has presented a major hurdle. Designer bifunctional photocatalysts containing a H-bonding motif for substrate recognition and a diaryl ketone as the photosensitizer embedded in a chiral scaffold are useful catalysts in asymmetric radical transformations. Herein, an overview of enantioselective transformations in which this class of catalysts has been successful and future directions are discussed.