Flavins and their alloxazine isomers are key chemical scaffolds for bioinspired electron transfer strategies. Their properties can be fine-tuned by functional groups, which must be introduced at an early stage of the synthesis as their aromatic ring is inert towards post-functionalization. We show that the introduction of a remote metal-binding redox site on alloxazine and flavin activates their aromatic ring towards direct C–H functionalization. Mechanistic studies are consistent with a synthetic sequence involving ground state single electron transfer (SET) with an electrophilic source followed by radical-radical coupling. This unprecedented reactivity opens new opportunities in molecular editing of flavins by direct aromatic post-functionalization and the utility of the method is demonstrated with the site-selective C6 functionalization of alloxazine and flavin with a CF3 group, Br or Cl, that can be further elaborated into OH and aryl for chemical diversification.
Site-Selective Radical Aromatic C–H Functionalization of Alloxazine and Flavin through Ground-State Single Electron Transfer
Agnideep Das; Oscar Charpentier; Cheriehan Hessin; Jules Schleinitz; David Pianca; Nolwenn Le Breton; Sylvie Choua; Laurence Grimaud; Christophe Gourlaouen; Marine Desage-El Murr.
Angewandte Chemie, 2024, DOI:https://t.co/oWs9tjlhwV
Marine Desage-El Murr, équipe OMECA, Institut de Chimie (UMR 7177).