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Updated: Aug 30, 2025

Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch
Published on: February 7, 2022
Photocatalytic Isomerization of (E)-Anethole to (Z)-Anethole
Marvin Korff1,2, Tiffany O Paulisch1,3, Frank Glorius1,3
1Westfälische Wilhelms-Universität Münster, Chemical Biology of Ion Channels (Chembion), GRK 2515, Corrensstraße 48, D-48149 Münster, Germany.
Abstract:
Natural product (E)-anethole was isomerized to (Z)-anethole in a photocatalytic reaction. For this purpose, a self-designed cheap photoreactor was constructed. Among 11 photosensitizers (organo and metal complex compounds), Ir(p-tBu-ppy)3 led to the highest conversion. Triplet energies of (E)- and (Z)-anethole were predicted theoretically by DFT calculations to support the selection of appropriate photosensitizers. A catalyst loading of 0.1 mol% gave up to 90% conversion in gram scale. Further additives were not required and mild irradiation with light of 400 nm overnight was sufficient. As a proof of concept, (E)- and (Z)-anethole were dihydroxylated diastereoselectively to obtain diastereomerically pure like- and unlike-configured diols, respectively.
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