Redox Mediators in Visible Light Photocatalysis: Photocatalytic Radical Thiol–Ene Additions

Abstract

Synthetically useful radical thiol-ene reactions can be initiated by visible light irradiation in the presence of transition metal polypyridyl photocatalysts. The success of this method relies upon the use of p-toluidine as an essential additive. Using these conditions, high-yielding thiol-ene reactions of cysteine-containing biomolecules can be accomplished using biocompatibile wavelengths of visible light, under aqueous conditions, and with the thiol component as the limiting reagent. We present evidence that p-toluidine serves as a redox mediator that is capable of catalyzing the otherwise inefficient photooxidation of thiols to the key thiyl radical intermediate. Thus, we show that co-catalytic oxidants can be important in the design of synthetic reactions involving visible light photoredox catalysis.

DOI: 10.1021/jo500031g

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Cite this paper

@inproceedings{Tyson2014RedoxMI, title={Redox Mediators in Visible Light Photocatalysis: Photocatalytic Radical Thiol–Ene Additions}, author={Elizabeth L. Tyson and Zachary L. Niemeyer and Tehshik P Yoon}, booktitle={The Journal of organic chemistry}, year={2014} }