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Inverting the reactivity of troponoid systems in enantioselective higher-order cycloaddition
Sebastian Frankowski1, Anna Skrzyńska1, Łukasz Albrecht1
1Institute of Organic Chemistry, Faculty of Chemistry, Lodz University of Technology, Żeromskiego 116, 90-924 Łódź, Poland. lukasz.albrecht@p.lodz.pl.
Abstract:
By the replacement of the oxygen with the sulfur atom in tropone, a novel reactivity pattern of troponoid systems in enantioselective transformation was achieved. It utilizes tropothione as an 8π-component in the [8+2]-cycloaddition involving α,β-unsaturated aldehydes. The stereochemistry of the process is governed through the aminocatalytic LUMO-activation of the carbonyl reactant. It is in marked contrast to recently developed aminocatalytic higher-order cycloadditions proceeding via HOMO-activation strategies.
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