Herein, we investigate the use of organic photocatalysts in the visible light-promoted β-functionalization of carbonyl compounds. In particular, we studied the addition of aliphatic aldehydes to α,β-unsaturated compounds (β-Michael addition), and the reaction of cyclic ketones with either ketones (β-aldol condensation) or imines (β-Mannich reaction). Among the dyes tested, donor-acceptor cyanoarenes gave the best results, promoting the transformations of interest in moderate to good yields. The reaction scope was investigated on substrates with different steric and electronic properties. Fluorescence quenching analysis (Stern-Volmer experiments) led us to propose for these reactions a reductive quenching mechanism involving a transient 5πe- activation mode.
Visible Light-Promoted β-Functionalization of Carbonyl Compounds in the Presence of Organic Dyes / L. Dolcini, T. Gandini, R. Castiglioni, A. Bossi, M. Penconi, A. DAL CORSO, C. Gennari, L. Pignataro. - In: JOURNAL OF ORGANIC CHEMISTRY. - ISSN 0022-3263. - 2023:(2023 Oct 04), pp. 1-9. [Epub ahead of print] [10.1021/acs.joc.3c00890]
Visible Light-Promoted β-Functionalization of Carbonyl Compounds in the Presence of Organic Dyes
L. DolciniPrimo
;T. GandiniSecondo
;A. DAL CORSO;C. GennariPenultimo
;L. Pignataro
Ultimo
2023
Abstract
Herein, we investigate the use of organic photocatalysts in the visible light-promoted β-functionalization of carbonyl compounds. In particular, we studied the addition of aliphatic aldehydes to α,β-unsaturated compounds (β-Michael addition), and the reaction of cyclic ketones with either ketones (β-aldol condensation) or imines (β-Mannich reaction). Among the dyes tested, donor-acceptor cyanoarenes gave the best results, promoting the transformations of interest in moderate to good yields. The reaction scope was investigated on substrates with different steric and electronic properties. Fluorescence quenching analysis (Stern-Volmer experiments) led us to propose for these reactions a reductive quenching mechanism involving a transient 5πe- activation mode.File | Dimensione | Formato | |
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Pignataro_SI_JOC_2023_ASAP.pdf
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