Arylamines are common substrates amongst pharmaceuticals, agrochemicals, dyes, and pigments. Typically, these are synthesized via (aryl nitration and) reduction of nitro-groups either with catalytic transition metal reduction under H2 atmosphere, or with stoichiometric reagents. However, the above-mentioned methodologies are often unselective and have poor functional group tolerance. Recently, different reductive photocatalytic approaches for nitrophenyls have been developed with and without sacrificial reductants. Previously, our research group has developed a photoreductive methodology for O-debenzylation of N-heterocycles, where reduction potential of the protonated N-heterocycle was used to select either a milder ([Ru(bpy)3]2+) or more powerful ([Ir[dF(CF3)ppy]2(dtbbpy)]3+) photoreductant. The reduction was selective in the presence of a wide set of functional groups, but proved to be unsuitable for nitroquinoline derivatives. A closer examination of the product distribution revealed reduction of the nitro-group to be a competing reaction, and optimization of the reaction conditions allowed for a selective conversion of nitro-groups to amines. Computational analysis, control experiments, and photocatalyst quenching experiments revealed that the reduction is a multi-site proton-coupled electron transfer (MS-PCET) reaction between the photocatalyst (electron acceptor), nitroquinoline (proton acceptor) and ascorbic acid (electron and proton donor).

Photoreduction of quinolines: Nitro reduction to amines and O-debenzylation by proton-coupled electron transfer

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.