Bulletin of the Korean Chemical Society

Korean Chemical Society (대한화학회)
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Theoretical Studies on the Electrophilic Methylation of Five-Membered Heteroaromatic Compounds with Dimethylfluoronium Ion

  • Chang Kon Kim (Department of Chemistry, Inha University) ;
  • Ikchoon Lee (Department of Chemistry, Inha University) ;
  • Bon-Su Lee (Department of Chemistry, Inha University)
  • Published : 1991.10.20
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Abstract

Electrophilic methylation reactions of five-membered heteroaromatic compounds, furan, pyrrole and thiophene, with the dimethylfluoronium ion, ${CH_3}{FCH_3}(+), have been investigated theoretically by the MNDO method. The site selectivity of ${\alpha}, {\beta}$ and heteroatom (X) is related to charge density of the site, indicating that the site selectivity is dictated by electrosatic interaction between two reaction centers. The reactivity order between the three heteroaromatics can not be determined decisively since the order differs depending on which site is compared, with relatively low activation enthalpies, ${\Delta}{H^\neq}$= 20-30 kcal/mol, in all cases. These site and substrate selectivity behaviors are consistent with the gas-phase experimental results.

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