Work

Room temperature decarboxylative cyanation of carboxylic acids using photoredox catalysis and cyanobenziodoxolones: a divergent mechanism compared to alkynylation

Year: 2016

Type: article

Abstract: the merger of visible light mediated photoredox and cyanobenziodoxolones (CBX) reagents. The reaction proceeded in high yields with natural and non-natural α-amino and α-oxy acids, affording a broad scope of nitriles with excellent tolerance of the substituents in the α position. The direct cyanation of dipeptides and drug precursors was also achieved. The mechanism of the decarboxylative cyanation was investigated both computationally and experimentally and compared with the previously developed alkynylation reaction. Alkynylation was found to favor direct radical addition, whereas further oxidation by CBX to a carbocation and cyanide addition appeared more favorable for cyanation. A concerted mechanism is proposed for the reaction of radicals with EBX reagents, in contrast to the usually assumed addition elimination process.

Source: Chemical Science

DOI: 10.1039/c6sc04907a

Authors: Franck Le Vaillant, Matthew D. Wodrich, Jérôme Waser

Institution: École Polytechnique Fédérale de Lausanne

Language: English

Topic: Radical Photochemical Reactions

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: diamond

Funders: École Polytechnique Fédérale de Lausanne, FP7 Ideas: European Research Council

Award: Hypervalent Iodine Reagents: A Tool Kit for Accessing Molecular Complexity