Work

Overcoming Back Electron Transfer Facilitates the Implementation of Electron Donor-Acceptor Complexes in Catalysis

Year: 2020

Type: preprint

Abstract: Electron donor-acceptor (EDA) complexes can controllably generate radicals under mild conditions through selective photoexcitation events. However, unproductive reactivity from fast deactivation of the photoexcited complexes through back electron transfer has slowed the development of EDA complexes in synthetic methodology. Here, we disclose the study of EDA complexes derived from 2-methoxynaphthalene donor and acylated ethyl isonicotinate N-oxide acceptor that undergo a fast N–O bond fragmentation event upon photoexcitation. This reaction design not only overcomes the limitations of back electron transfer but also enables the regeneration of the donor species, representing a rare example EDA photochemistry in a catalytic regime. The synthetic utility is demonstrated through visible light-driven radical trifluoromethylation and Minisci alkylation reactions. The scalability of the EDA complex promoted reaction evidenced by the successful multigram-scale trifluoromethylation of methyl N-Boc pyrrole-2-carboxylate in a continuous flow manifold.

Source: ChemRxiv

DOI: 10.26434/chemrxiv.12130011

Authors: Edward McClain, Timothy Monos, Mayuko Mori, Joel Beatty, Corey Stephenson

Institution: University of Michigan

Language: English

Topic: Radical Photochemical Reactions

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: green

Funders: National Science Foundation, University of Michigan, Division of Chemistry

Awards: Redox catalysis strategies for synthesis, G8654503962, G895164487