Enantioselective Photocatalysis Using a Privileged Al–Salen Complex

• DOI: 10.1021/acs.accounts.5c00194
• Publication Date: 2025-05-01T00:08:42Z
• Authors: Julia Soika; Carina Onneken; Tobias Morack; Ryan Gilmour

ConspectusEnantioselective catalysts that exhibit broad generality are disruptive innovators in contemporary synthesis and considered to be "privileged" on account of their expansive reactivity/selectivity profiles. Operating the ground state, these species simultaneously regulate reactivity orchestrate translation chiral information with exquisite efficiency: achieving parity higher-energy (excited-state) scenarios remains a frontier catalysis. Advancing this field will require new structure-activation guidelines delineated reflect energetic realities induction non-ground-state environments, thereby expediting discovery privileged photocatalysts. Earth-abundant aluminum-salen (Al-salen) complexes, which have venerable history ground-state enantioselective catalysis, show great promise reconciling disparity well-defined photophysical properties. In Account, potential engaging various substrates via discrete activation modes furnish optically enriched products high levels reliability is discussed. The deployment commercial Al-salen complexes single electron transfer (SET)-enabled deracemization cyclopropyl ketones an exemplar. Irradiation complex augments function catalyst enable efficient (up 98:2 e.r.), eliminating need for directing units. stark contrast conventional approaches predicated C(sp3)-H deprotonation/reprotonation sequences, transformation characterized by key C(sp3)-C(sp3) bond cleavage/cyclization process. Subsequent downstream manipulations enantioenriched demonstrate synthetic utility methodology. To illustrate mechanistic diversity using same complex, photocyclization under auspices energy (EnT) catalysis described. acrylanilides operationally simple conditions facilitates access diverse group heterocyclic quantitative yield 96:4 e.r.) as sole operator. Collectively, mechanistically distinct light powerful strategy augment arsenal ubiquitous small molecule state. foundations reaction development surveyed (combined experimental computational approach), together perspective impact enabling technology functional discovery. This Account serves emphasize leveraging photochemical mitigate intrinsic constraints processes might thermochemically challenging.