Light-Enabled Deracemization of Cyclopropanes by Al-Salen Photocatalysis

Privileged chiral catalysts continue to transform the reactivity landscape, but achieving parity in excited state paradigms remains a frontier in contemporary synthesis. Whilst the interception of photogenerated intermediates by ground state cycles has partially addressed this challenge, single, chiral photocatalysts that simultaneously regulate reactivity and selectivity remain conspicuously scarce. Existing strategies leverage precision donor-acceptor recognition motifs to orchestrate enantioinduction. Expanding the latitude of this emerging branch of photocatalysis to incorporate simple, ubiquitous recognition units would be highly enabling but requires a suite of privileged photocatalysts. Motivated by the well-defined photo-physical properties of chiral Al-salen complexes, the efficiency of this privileged catalyst has been investigated and validated in the highly enantioselective deracemization of cyclopropyl ketones (up to 98:2 e.r.).