Preferential Crystallization of a Helicene–Viologen Hybrid – An Efficient Method to Resolve [5]Helquat Enantiomers on a 20 g Scale

Authors

  • Jan Vávra,

    1. Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v. v. i. Flemingovo nám. 2, 16610 Prague 6, Czech Republic, Fax: +420-220-183-578
    Search for more papers by this author
  • Lukáš Severa,

    1. Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v. v. i. Flemingovo nám. 2, 16610 Prague 6, Czech Republic, Fax: +420-220-183-578
    Search for more papers by this author
  • Pavel Švec,

    1. Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v. v. i. Flemingovo nám. 2, 16610 Prague 6, Czech Republic, Fax: +420-220-183-578
    Search for more papers by this author
  • Ivana Císařová,

    1. Department of Inorganic Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030, 12840 Prague 2, Czech Republic
    Search for more papers by this author
  • Dušan Koval,

    1. Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v. v. i. Flemingovo nám. 2, 16610 Prague 6, Czech Republic, Fax: +420-220-183-578
    Search for more papers by this author
  • Petra Sázelová,

    1. Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v. v. i. Flemingovo nám. 2, 16610 Prague 6, Czech Republic, Fax: +420-220-183-578
    Search for more papers by this author
  • Václav Kašička,

    1. Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v. v. i. Flemingovo nám. 2, 16610 Prague 6, Czech Republic, Fax: +420-220-183-578
    Search for more papers by this author
  • Filip Teplý

    1. Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v. v. i. Flemingovo nám. 2, 16610 Prague 6, Czech Republic, Fax: +420-220-183-578
    Search for more papers by this author

  • Dedicated to Dr. Ivo Starý on the occasion of his 50th birthday

Abstract

The bistriflate salt of racemic [5]helquat 1 was found to form a conglomerate. Based on this finding, the preferential crystallization of this chiral helicene–viologen hybrid was developed to deliver pure enantiomers on a 20 g scale (10.5 g of each enantiomer). To the best of our knowledge, this is the largest amount of nonracemic helicene-like compound obtained by preferential crystallization to date. The absolute configuration of the P enantiomer was confirmed by X-ray crystal structure analysis. The chromatography-free synthesis of racemic 1 on a multigram scale (30 g) is also presented as an entry point to this resolution study.

Ancillary