Site-Selective, Photocatalytic Vinylogous Amidation of Enones
Kitti Franciska Szabó, Katarzyna Goliszewska, Jakub Szurmak, Katarzyna Rybicka-Jasińska* and Dorota Gryko*
*Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland, Email: krybicka-jasinskaicho.edu.pl, dorota.grykoicho.edu.pl
K. F. Szabó, K. Goliszewska, J. Szurmak, K. Rybicka-Jasińska, D. Gryko, Org. Lett., 2022, 24, 8120-8124.
see article for more reactions
A mild and efficient photocatalytic vinylogous reaction of dienolates with N-amino pyridinium salts provides γ-amido carbonyl compounds. This process is high-yielding, scalable, and tolerates a broad range of starting materials.
see article for more examples
General synthetic procedure for visible-light mediated amidation of enols
A glass vial equipped with a stirring bar and sealed with a septum was charged with an enol (if solid, 0.25 mmol, 1.0 equiv.), fac-Ir(ppy)3 (0.01875 mmol, 0.75 mol%) and an N-aminopyridinium salt (0.33 mmol, 1.3 equiv.). Anhydrous MeCN (5 ml) was added, and the resulting mixture was degassed by argon bubbling for 20 minutes. Subsequently, (enol if liquid, 0.25 mmol, 1.0 equiv. was added) the reaction mixture was placed in a photoreactor and irradiated with blue LED for the time specified. Then, the mixture was transferred to a roundbottom flask and concentrated in vacuo. A crude product was purified by flash column chromatography using hexane/EtOAc mixture as an eluent.
allylic amines, photochemistry