Selective photooxygenations and oxidative C−H-functionalizations of indole alkaloids and polycyclic terpenes through quinone photoorganocatalysis

• Applicant: Professor Dr. Malte Brasholz
• Subject Area: Organic Molecular Chemistry - Synthesis and Characterisation
• Term: from 2014 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 266793065

• Final Report Year: 2022

Final Report Abstract

As shown in this project, benzo- and anthraquinones are versatile photoorganocatalysts for aerobic oxidative transformations of amines and N-heterocycles, whereby the photophysical properties determined by their individual substitution patterns allow a problem-adapted catalyst selection. Using quinone photoorganocatalysis, Csp3-H oxygenations, amine oxidations and new syntheses of indoloquinolines and functionalized isoquinolines could be developed. Furthermore, new applications in the photooxygenation of indole alkaloids have been developed.

Publications

• Visible light cascade photooxygenation of tetrahydrocarbazoles and cyclohepta[b]- indoles: access to C,N‐diacyliminium ions. Angew. Chem. Int. Ed. 2020, 59, 12450-12454
  M. Frahm, T. von Drathen, L. M. Gronbach, A. Voss, F. Lorenz, J. Bresien, A. Villinger, F. Hoffmann, M. Brasholz
  (See online at https://doi.org/10.1002/anie.202007549)
• Lewis Acid-Catalyzed Carbofunctionalization of Uncommon C,N-Diacyliminium Ions: Controlling Regio- and Enantioselectivity. Org. Lett. 2021, 23, 7834-7838
  L. M. Gronbach, A. Voss, M. Frahm, A. Villinger, J. Bresien, D. Michalik, M. Brasholz
  (See online at https://doi.org/10.1021/acs.orglett.1c02857)
• A short total synthesis of (±)-mersicarpine via visible light-induced cascade photooxygenation. Chem. Commun. 2022, 58, 5467-5469
  M. Frahm, A. Voss, M. Brasholz
  (See online at https://doi.org/10.1039/d2cc01316a)