Photocatalytic Isomerization of (<i>E</i>)-Anethole to (<i>Z</i>)-Anethole
Marvin Korff,
Tiffany O. Paulisch,
Frank Glorius,
Nikos L. Doltsinis,
Bernhard Wünsch
Affiliations
Marvin Korff
Westfälische Wilhelms-Universität Münster, Chemical Biology of Ion Channels (Chembion), GRK 2515, Corrensstraße 48, D-48149 Münster, Germany
Tiffany O. Paulisch
Westfälische Wilhelms-Universität Münster, Chemical Biology of Ion Channels (Chembion), GRK 2515, Corrensstraße 48, D-48149 Münster, Germany
Frank Glorius
Westfälische Wilhelms-Universität Münster, Chemical Biology of Ion Channels (Chembion), GRK 2515, Corrensstraße 48, D-48149 Münster, Germany
Nikos L. Doltsinis
Westfälische Wilhelms-Universität Münster, Institut für Festkörpertheorie und Center for Multiscale Modelling and Computation, Wilhelm-Klemm-Straße 10, D-48149 Münster, Germany
Bernhard Wünsch
Westfälische Wilhelms-Universität Münster, Chemical Biology of Ion Channels (Chembion), GRK 2515, Corrensstraße 48, D-48149 Münster, Germany
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.
