- Minisci-Type Alkylation of N-Heteroarenes by N-(Acyloxy)phthalimide Esters Mediated by a Hantzsch Ester and Blue LED Light
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A synthetic method that enables the Hantzsch ester-mediated Minisci-type C2-alkylation of quinolines, isoquinolines and pyridines by N-(acyloxy)phthalimide esters (NHPI) under blue LED (light emitting diode) light (456 nm) is described. Achieved under mild reaction conditions at room temperature, the metal-free synthetic protocol was shown to be applicable to primary, secondary and tertiary NHPIs to give the alkylated N-heterocyclic products in yields of 21–99%. On introducing a chiral phosphoric acid, an asymmetric version of the reaction was also realised and provided product enantiomeric excess (ee) values of 53–99%. The reaction mechanism was delineated to involve excitation of an electron-donor acceptor (EDA) complex, formed from weak electrostatic interactions between the Hantzsch ester and NHPI, which generates the posited radical species of the redox active ester that undergoes addition to the N-heterocycle.
- Kyne, Sara Helen,Li, Jiacheng,Siang Tan, Suan,Wai Hong Chan, Philip
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supporting information
(2022/01/11)
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- Radiochemical 18F-fluoroarylation of unsaturated α-, β- and γ-amino acids, application to a radiolabelled analogue of baclofen
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Unsaturated α-, β- and γ-amino acids have been investigated as substrates for the reductive Meerwein arylation. Radical reactions of this type have been shown to be a valuable tool for the fast and efficient introduction of the 4-[18F]fluorophenyl group into precursor molecules allowing short-time syntheses of potential PET radiotracers, which would be more difficult to access by other methods.
- H?fling, Sarah B.,Hultsch, Christina,Wester, Hans-Jürgen,Heinrich, Markus R.
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experimental part
p. 11846 - 11851
(2009/04/06)
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