Asymmetric Alkylation via Photoredox Pathway Using a Chiral Iridium Complex
Asymmetric Photoredox Transition-Metal Catalysis Activated by Visible Light.
19. Januar 2015 (online)
Key wordsphotoredox catalysis - enantioselective alkylation - 2-acyl imidazoles - visible light - iridium
The authors demonstrate a unique example of asymmetric redox catalysis achieved by visible light. Two catalytic cycles are connected by the key intermediate, an iridium(III) enolate complex, which is an active photosensitizer generated in situ.
This process provides very mild conditions and excellent yields and enantioselectivities. The reaction proceeds via a photoredox mechanism, supported by X-ray, radical trapping, luminescence quenching, and interval experiment analyses.