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Updated: Jul 1, 2025

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species
Published on: August 16, 2018
Persistent guaiazulene arylmethylium ions as electrophilic traps for metal enolates
Péter Kisszékelyi1, Brigita Mudráková1, Marek Cigáň1
1Comenius University Bratislava, Faculty of Natural Sciences, Department of Organic Chemistry, Mlynská dolina, Ilkovičova 6, Bratislava 842 15, Slovakia. radovan.sebesta@uniba.sk.
Abstract:
Guaiazulene-stabilized cations reacted with metal enolates affording carbonyl compounds with an azulene moiety. Metal enolates generated by asymmetric conjugate addition of organometallic reagents led to enantioenriched products. Additionally, guaiazulene-substituted cations efficiently react with silyl enol ethers. DFT calculations allowed estimation of the electrophilicities of the carbocations. Reaction progress was monitored by a decrease in the reactant's Vis-light absorption and an increase in the product's anti-Kasha emission.
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