Kolbe Anodic Decarboxylation as a Green Way To Access 2-Pyrrolidinones
Mathilde Quertenmont, Iain Goodall, Kevin Lam*, István Markó and Olivier Riant*
*University of Greenwich, Chatham Maritime ME4 4TB,
UK; Université Catholique de Louvain (UCL), 1348 Louvain-la-Neuve, Belgium,
Email: k.lam
greenwich.ac.uk, olivier.riantuclouvain.be
M. Quertenmont, I. Goodall, K. Lam, I. Markó, O. Riant, Q. Wan, Org. Lett., 2020, 22, 1771-1775.
DOI: 10.1021/acs.orglett.0c00056
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Abstract
Electrosynthesis enables an effective and environmentally friendly pyrrolidinone synthesis via Kolbe decarboxylation, followed by an intramolecular radical cyclization and a radical-radical cross-coupling.
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General Procedure for the electrocyclization of pyrrolidinones
In an undivided cell with platinium electrodes (4 cm˛), potassium hydroxide (7.5 mmol, 5 equiv) and the carboxylic acid (7.5 mmol, 5 equiv) were dissolved in MeOH. Then, potassium salt (1.5 mmol, 1 equiv, 66 mM in methanol) was added to the mixture. The intensity of the current was fixed at 100 mA and the mixture was electrolyzed until completion of the reaction, as shown by TLC. The solution was treated with an aqueous solution of NaHCO3 and extracted 3 times with Et2O. The combined organic layers were dried over MgSO4 and concentrated under reduced pressure. The crude product was purified by silica gel chromatography.
Key Words
γ-lactams, Kolbe Electrolysis, electrochemistry
ID: J54-Y2020
